Summarizing Research on Companion Animal Population Dynamics and

Control Practices, and Exploring Factors Impacting Dogs’ Time to Adoption

in a Shelter System

by

Aileigh Kay

A Thesis

presented to

The University of Guelph

In partial fulfilment of requirements

for the degree of

Master of Science

in

Population Medicine

Guelph, Ontario, Canada

© Aileigh Kay, May, 2016

ABSTRACT

SUMMARIZING RESEARCH ON COMPANION ANIMAL POPULATION DYNAMICS

AND CONTROL PRACTICES, AND EXPLORING FACTORS IMPACTING DOG’S

TIME TO ADOPTION IN A SHELTER SYSTEM

Aileigh Kay Advisor:

University of Guelph, 2016 Dr. Jason B. Coe

A scoping review was conducted to identify all globally published literature investigating

population dynamics and control practices of companion animals. There were 7810 unique

citations initially identified, 869 articles (450 primary research and 419 reviews) were confirmed

relevant. Most articles were conducted in the United States (359; 41.3%) and the main focus was

on control practices (697; 80.2%). Among primary research articles, 204 (45.3%) investigated

reproduction control, identifying an opportunity for further knowledge synthesis efforts. A Cox

proportional frailty hazard analysis was conducted to determine factors that affect dogs’

(n=8,325) time to adoption within the British Columbia Society for the Prevention of Cruelty for

Animals’ shelter system, between January 2010 and July 2014. Results demonstrated surrender

reason, age, where animal was obtained, coat colour, breed, human population density of shelter

location and incoming year significantly influenced dogs’ time to adoption. Findings suggest

areas for targeted adoption promotion by shelters.

iii

ACKNOWLEDGEMENTS

I would not have been able to complete my thesis without the support and help from

many important and special people. First, I would like to thank my advisor Dr. Jason Coe,

throughout this process you provided not only an opportunity for me to conduct research but on-

going expertise, guidance and support, which I am extremely grateful for. During this process,

you also pushed me to improve my writing, thinking and research skills. I would also like to

thank you for the time and resources you dedicated to aid in my success. To my advisory

committee, to Dr. David Pearl specifically, thank you for providing extra time to help me

through the survival analysis statistics; it made statistics easier to complete and understand. I

appreciate your on-going patience. To Dr. Ian Young thank you for providing your expertise and

expanding my knowledge by teaching me different research methods. I appreciate the support

and advice you have provided.

Thank you to Nestlé Purina Pet Care Canada Chair in Communications for funding these

projects.

I would like to thank the British Columbia Society for the Prevention of Cruelty to

Animals (BC SPCA) for providing access to their database. I appreciate all the work and time

you dedicated to ensure all my questions were answered either through email correspondence or

phone calls.

These projects would not have been successful without the help of my colleagues Dr.

Kim Lambert and Rachel O’Connor. Dr. Kim Lambert, you provided excellent guidance for my

scoping review chapter. I appreciated your patience when I asked you question after question and

your willingness to help, it allowed this project to progress smoothly and successfully. Rachel,

words cannot begin to describe how thankful I am for all the work you have done. You helped

iv

with many aspects of the scoping review chapter and your dedication and hard work were vital to

this project’s success. I would also like to thank you both of you for your emotional support:

your advice, kindness and stories made this experience a little less stressful and way more

enjoyable.

To the many research assistants I had reading articles for me. I know reading article after

article and answering the same questions over again is not the most exciting work, but it was

greatly appreciated. Each one of you were an extremely important member of this research

project. I want to thank Chandi Priyanatha, you worked for me the longest. You were dedicated

to your work and you were flexible when it came to extending your work periods and flexible

with tasks that were assigned. All your hard work helped move this thesis along.

Friends, old and new, your support was one of the reasons why I made it through this

program. I met many amazing, intelligent and driven people while completing this program and

together we were able to be successful. You were there for all the ups and downs; to listen,

provide support and comfort, or just comfort food. You embraced my hedgehog obsession by

sharing photos and videos which always brightened my days. After I moved to Toronto, many of

you provided me with a place to stay; I was a travelling nomad and you definitely made

commuting a lot easier and more enjoyable. I enjoyed all the laughs and tears we shared. I was

truly blessed to have met each and every one of you and I am proud of all that we have

accomplished. Old friends, this is not the first time you have been there for me throughout my

educational career. You have provided unconditional support, a place to escape to when it was

necessary and when all I needed was some company. You always believed in me and words

cannot express how much that meant. You rock!

v

Lastly, I want to thank my parents and my sister. I am very grateful for all the love and

support you have provided during this journey. I appreciate your interest in my research and for

listening to my rants even though I know sometimes it sounded like complete gibberish to you.

You have always supported my ambition and goals even when I was not sure I could achieve

them. Your unwavering belief in me and my abilities made it possible to keep going; thank you

for always pushing me forward and keeping me well fed along the way.

vi

STATEMENT OF WORK DONE

Aileigh Kay designed the methodology and the statistical approach to analyze the results

for both the scoping review and quantitative study of this thesis with the advisement of Dr. Jason

Coe and cooperation of her advisory committee, Dr. Ian Young and Dr. David Pearl.

Chapter 1: Literature Review

Aileigh Kay wrote the literature review under the direction of Dr. Jason Coe. Carol Tinga

provided editorial coaching on this chapter. Dr. Ian Young and Dr. David Pearl contributed

additional feedback and revision recommendations.

Chapter 2: Scoping Review

The research question was derived through collaboration with Drs. Jason Coe and Kim Lambert.

Aileigh Kay wrote the scoping review protocol and developed review materials with support and

inputs from Dr. Jason Coe and Dr. Ian Young. The search string was created by Aileigh Kay and

lab colleague Dr. Kim Lambert, it was initially implemented by colleagues Dr. Kim Lambert and

Elpida Artemiou and later re-implemented by Aileigh Kay and Elpida Artemiou. Aileigh Kay

was responsible for citation management and deduplication. Relevance screening was completed

by Aileigh Kay and lab colleague Rachel O’Connor, relevant articles were procured by Aileigh

Kay, Rachel O’Connor and research assistant Chanditha Priyanatha. Data extraction was

completed by Aileigh Kay, Rachel O’Connor and research assistants: Chanditha Priyanatha, Lea

Nogueira Borden, Jennifer MacNicol, Olivia Pereira, Emilie Belage, and Luz Kisiel. Aileigh Kay

characterised and analysed the results with advice and feedback from Dr. Jason Coe, and Dr. Ian

Young. The first draft manuscript was written by Aileigh Kay. The manuscript was edited and

reviewed by Drs. Jason Coe, David Pearl, and Ian Young.

vii

Chapter 3: Quantitative Study: Survival Analysis

Dr. Jason Coe and Aileigh Kay worked together to determine the methodology with

contributions from Dr. David Pearl and Dr. Ian Young. Data were extracted and initially cleaned

and organized by Chanditha Priyantha with guidance from Aileigh Kay and Dr. Jason Coe. Dr.

David Pearl provided additional consultation on the survival analysis process and analysis.

Aileigh Kay recoded the data, prepared, completed and interpreted the results with the aid of Dr.

Jason Coe, and Dr. David Pearl. The first draft of the manuscript was written by Aileigh Kay.

The manuscript was reviewed and edited by Dr. Jason Coe throughout development. Additional

edits and comments were received from Dr. David Pearl and Dr. Ian Young.

Chapter 4: Conclusions

Aileigh Kay wrote the first draft of the conclusions with feedback and edits from Dr. Jason Coe.

Dr. Ian Young and Dr. David Pearl provided additional recommended edits and remarks.

viii

TABLE OF CONTENTS

CHAPTER ONE ...………………………………………………………………………………. 1

Introduction, Literature Review, Rationale and Objective……….……………………… 1

1.0 Introduction..…………………………………………………………………. 2

1.1 Literature Review…………………………………………………………….. 3

1.1.1 Number of owned and unowned companion animals……. 3

1.1.2 Role of companion animals in human lives……………… 4

1.1.3 Stakeholders……………………………………………… 8

1.1.4 International scope……………………………………… 10

1.1.4.1 Values…………………………………... 10

1.1.4.2 Laws…………………………………….. 11

1.1.4.3 Socio-Economics……………………….. 12

1.1.4.4 Climate………………………………….. 14

1.1.5 Control Practices………………………………………... 14

1.1.5.1 Spay and Neuter………………………… 15

1.1.5.2 Trap Neuter Release…………………….. 17

1.1.5.3 Non-Surgical Contraception…..……….. 19

1.1.5.4 Euthanasia………………………………. 22

1.1.5.5 Other Control Practices…………………. 23

1.1.6 Shelter Management……………………………………. 25

1.1.7 Characteristics of shelter animals being adopted or

euthanized………………………………………………. 29

1.1.8 Methodology……………………………………………. 32

1.2 Thesis Rationale…………………………………………………………….. 33

ix

1.3 Thesis Objectives…………………………………………………………… 34

References………………………………………………………………………. 35

CHAPTER TWO...……...……………………………………………………………………… 45

A Scoping Review of Published Research on the Population Dynamics and Control Practices of

Companion Animals……………………………….…………………………..……………….. 45

Abstract…………………………………………………………...…………………….. 46

Introduction………………………..……………………………………………………. 47

Methods……………………...……..……………………………………….................... 49

Review protocol, team, question and scope…………………………………….. 49

Search Strategy…………………………………………………………………. 50

Relevance Screening……………………………………………………………. 51

Article Procurement…………………………………………………………….. 52

Data Characterization and Extraction…………………………………………... 52

Review Management, Data Charting and Analysis…………………………….. 53

Results.................................................................................................................….......... 54

Descriptive characteristics of published research on population dynamics and

control practices………………………………………………………………… 54

Characteristics of Primary Research……………………………………………. 56

Discussion………………………………………………………………………………. 58

Conclusion…………………………………………………………………………….... 66

References……………………………………………………………………………….68

CHAPTER THREE.…………………………………………………….……………………… 92

Factors influencing time to adoption for dogs in a provincial shelter system in Canada….…… 92

x

Abstract.………………………………………………………………………...………. 93

Introduction…………….……………………………………………………………….. 94

Methods...……………………………………………………………………………….. 95

Description of Data Set…………………………………………………………. 95

Statistical Analysis…………………………………………………………….... 99

Results ….…………………………………………………………………………...… 100

Study Population………………………………………………………………. 101

The Effect of Shelter and Animal Characteristics on Length of Stay in the

Shelter………………………………………………………………………..... 102

Discussion……………………………………………………………………………... 104

Conclusions………………………………...………………………………………….. 113

References……………………………………………………………………………... 114

CHAPTER FOUR.…………………………………………………………………………….. 128

Conclusions………...………………………………………………………………….. 128

Summary of Findings………...………………………………………………………... 130

A Scoping Review of the Published Research on the Population Dynamics and

Control Practices of Companion Animals…………………………………….. 131

Factors Influencing Time to Adoption for Dogs in a Provincial Shelter System in

Canada…………………………………………………………………………. 132

Key Recommendations…………………………………….………………………….. 134

Thesis Limitations..….………………………………………………………………… 135

Future Directions for Research……….……………………………………………..… 136

References………………………………………………………………..……………. 139

APPENDIX A ……………………………..………………………………………………….. 141

A.1: Database Specific Search Strings………………………..…………………….... 142

xi

A.2: Relevance Screening Form……………………………………………………… 147

A.3: Data Extraction and Characterization Form…………………………………….. 152

A.4: Reference list of included 869 articles…….…………………………………..… 167

A.5: Description of non-English articles excluded from the study…........................... 219

A.6: Description of articles unable to obtain excluded from the study………………. 225

xii

LIST OF TABLES

2.1: Key definitions used in the relevance screening and data extraction form.......………....… 73

2.2: Descriptive characteristics of 869 primary research and review and commentary articles

investigating or discussing the issue of companion animal population dynamics…..….…. 75

2.3: Main areas of focus in the 869 primary research and review and commentary articles

investigating or discussing the issue of companion animal population dynamics……….... 77

2.4: Author-reported recommendations from the 869 primary research and review and

commentary articles investigating or discussing the issue of companion animal population

dynamics……………………...………………………………………………………….… 81

2.5: Methodological, outcomes and reporting characteristics of 450 primary research articles

investigating the issue of companion animal population dynamics……………………….. 84

2.6: Scoping review evidence map identifying the number of studies investigating control

practices among 301 primary research articles…………………………………………….. 86

3.1: Descriptive statistics of categorical independent variables on dog and shelter characteristics

among BC SPCA shelters, 2010–2014…………………………………………………… 117

3.2: Survival analysis main effects model of 8325 dogs that entered a BC SPCA shelter between

January 2010 and July 2014……………………………………………………………… 120

3.3: Significant categorical variable contrasts of the survival analysis of dogs that entered a BC

SPCA shelter between January 2010 and July 2014……………………………………... 123

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LIST OF FIGURES

2.1: Scoping review flow-chart………………………………………….……………………… 88

2.2: Frequency of published articles by year……………………………….…..………….…… 89

2.3: Scoping-review evidence map of the key aspects and themes among 450 primary-research

articles stratified by year of publication…………………...…………….………………… 90

2.4: Scoping-review evidence map of the key aspects and themes among 450 primary-research

articles stratified by study location.…………….………………………………..………… 91

3.1: Hazard ratios of the breed categories against the natural log of the length of time illustrating

the changing time to adoption of various breed categories relative to Border Collie

mixes................................................................................................................................… 124

3.2: Hazard ratios of the surrender reason categories against the natural log of time illustrating

the changing time to adoption of various surrender reason categories relative to

accommodation change......…………………………………………………………..…... 125

3.3: Hazard ratios of the original source categories against the natural log of time illustrating the

changing time to adoption of various original source categories relative to animal rescue 126

3.4: Hazard ratios of the population centres against the natural log of time illustrating the

changing time to adoption of various population centre categories relative to large

population centres…………………………………………………………..………….…. 127

1

CHAPTER ONE

Introduction, Literature Review, Thesis Rationale and Objectives

2

1.0 Introduction

Humans have been keeping companion animals for centuries with the belief that animals

contribute to human survival, health and healing (Walsh, 2009a). The role of companion animals

in human lives has increased over time; humans have increased the amount of money they spend

on their pets, are willing to do more to care for their pets and many humans even see their pets as

family members (Walsh, 2009a). The increase in this interspecies relationship (commonly

known as the human-animal bond (HAB) (Hines, 2003)), has led to an increase in the amount of

research that focuses on this relationship (Blazina, Boyraz and Shen-Miller, 2011). Much

evidence exists demonstrating that a successful HAB has a variety of beneficial effects for the

human involved including social, psychological, physiological and physical benefits (Edney,

1995; Jennings, 1997; Walsh, 2009a; Friedmann and Son, 2009). A successful human-animal

bond can also provide physiological benefits for the companion animal involved (Kostarczyk and

Fonberg, 1982; McGreevy, Righetti and Thomson, 2005). Although many positive benefits have

been identified, evidence also exists that unsuccessful HABs can have a variety of negative

consequences, that mainly effect the companion animal involved and often contribute to

companion animal overpopulation (Kass et al., 2001; Kass, 2007).

To date, a specific definition for “companion animal overpopulation” does not exist within

published literature. Given the lack of consensus regarding a definition, for the purpose of this

thesis, the term companion animal population dynamics will be used. Companion animal

population dynamics, which in part influence “overpopulation”, are affected by many factors

including reproduction, control practices, abandonment, relinquishment, and the environment.

Ultimately, these factors can result in the development of unowned free roaming and feral

populations, which contribute to overcrowded shelters. Overcrowded shelters can result in

3

negative outcomes for the animals in the shelters including increased stress, disease spread and

potentially lead to decreased adoptions (Hurley, 2005). Methods that have been identified to

prevent overcrowding are limiting admissions, euthanasia, and various approaches for decreasing

length of stay for each animal (Hurley, 2005). A variety of ownership practices can contribute to

companion animal population dynamics. For example, allowing pets to roam freely and choosing

not to spay and neuter them can lead to unwanted pregnancies. In addition, different ownership

and cultural practices can lead to differences in accepted management strategies and

interventions that can be used to control free roaming and feral animal populations.

Companion animal population dynamics is complex and affects countries worldwide, with many

different stakeholders being invested and interested in addressing the topic. As such, a variety of

control interventions have been attempted and researched. Stakeholders including public health

professionals, animal welfare professionals, and ecologists/conservationists have approached the

issue from different perspectives largely influenced by different objectives, resulting in different

recommendations for intervention.

1.1. Literature Review

1.1.1. Number of owned and unowned companion animals

Companion animals, mainly dogs and cats are commonly kept around the world. It was estimated

that in the United States in 2012 there were 70 million owned dogs and 74 million owned cats

(AVMA, 2012). In 2011, there were an estimated 5.9 million dogs and 7.9 million cats owned in

Canada (CVMA, 2011). Despite the difference in total numbers, the percentage of dogs and cats

owned in these two countries are similar. It has been reported that 36.5% of households in the

United States (AVMA, 2012) and 35% of households in Canada own a dog (CVMA, 2011). Also

30.4% of American households (AVMA, 2012) and 38% of Canadian households own a cat

4

(CVMA, 2011). In 2014, 9 million dogs and 7.9 million cats were owned in the United Kingdom

(U.K.) (PFMA, 2014). The percentage of dogs and cats owned in the U.K. is less compared to

Canada and the United States with 24% of households owning a dog and 18% owning a cat in

2014 (PFMA, 2014). Jayakumar (1997) completed a survey (year not specified), which estimated

there is 1 owned dog for every 11 households in India.

While the prevalence of companion animal ownership is important to know, it is perhaps more

important to know the population size of owned and unowned free roaming populations because

of their impact on companion-animal population dynamics. However, obtaining the latter can be

difficult. Studies have used community member surveys (Brooks, 1990; Levy et al., 2003a;

Toukhsati, et al., 2012; Otolorin, Umoh and Dzikwi, 2014) and various surveillance methods

(Jayakumar, 1997, MengChih et al., 2010; Hiby et al., 2011; Punjabi et al., 2012; Otolorin,

Umoh and Dzikwi, 2014; Tenzin et al., 2015) to estimate the size of owned and unowned, free-

roaming companion animal populations. The American Society for the Prevention of Cruelty to

Animals (ASPCA) (2014) stated that twice as many strays enter their shelters compared to

relinquished animals. Also, they estimated (methods not stated) that there were approximately 70

million stray cats in the United States (year not stated), but no estimation was provided for stray

dogs (ASPCA, 2014). The Canadian Federation of Humane Societies (CFHS) (2015a) stated that

53% of cats and 45% of dogs entering their shelters were stray in 2014. It is evident that there is

a large presence of companion animals, including free roaming and unwanted animals; however,

many countries likely have inaccurate estimates of their overall companion animal population

size since obtaining accurate data can be difficult.

1.1.2. Role of companion animals in human lives: benefits and consequences

5

Companion animals have been a common part of society for hundreds of years with a changing

role over recent decades, where obtaining companion animals for companionship and not

function has become more common (Grier, 2006; Walsh, 2009a). Many factors have contributed

to this change including increased wealth (in America), changes in demographics, the desire to

follow popular trends and curiosity of animal ownership (Grier, 2006). In the United States, 95%

of pet owners considered their pet as a friend and 87% considered their pet as a family member

(Walsh 2009a). Similarly, in the United Kingdom (U.K.), over 90% of pet owners considered

their pet as a family member (McNicholas et al., 2005). This type of relationship between the

owner and companion animal is called the human-animal bond (HAB) and has become widely

accepted over the past 30 years (Hines, 2003). Pet owners have stated that they share an

unconditional love with their pet and that their pet makes them feel safe (Rew, 2000; Walsh

2009b; Zilcha-Mano, Mikulincer and Shaver, 2011). For example, Rew (2000) interviewed

homeless youth and one youth stated that “dogs were companions that could provide safety,

unconditional love, and a reason to keep going because they needed care in return.” A study

comparing the feeling of security in human (romantic) relationships to pet relationships, found

participants felt less secure in their romantic relationships compared to their pet relationships

(Beck and Madresh, 2008). Furthermore, 52% of participants (N=182) strongly agreed with the

statement “I know my pet really loves me” compared to 39% of participants who strongly agreed

with the statement “I know my partner really loves me” (Beck and Madresh, 2008).

A positive bond can provide many health, social, physical, and psychological benefits for the

owner (Edney, 1995; Jennings, 1997; Walsh, 2009a; Friedmann and Son, 2009). A companion

animal can be part of an owner’s support system providing as much social support as a parent or

sibling (McConnell et al., 2011). Pet owners have been found to receive greater fulfillment of

6

their social needs from their pets and to be less lonely, happier, experience less stress

(McConnell et al., 2011), have greater self-esteem (Edney, 1995; McConnell et al., 2011) and

have fewer minor health problems (Serpell, 1991; Edney, 1995) compared to non-pet owners.

These results agree with a study examining the influence of owning a pet on stressful life events

and doctor services in elderly citizens. The study was a one year prospective study that

implemented telephone interviews (or face-face when necessary) every two months. The authors’

found that elderly pet owners had less stressful life events and less contact with doctors

compared to non-pet owners (Siegel, 1990). Furthermore, results supported that single

individuals with pets had fewer doctor visits, took less medication and were less lonely than

single individuals without pets (Zasloff and Kidd, 1994; Heady, 1999). Owning a pet can

increase physical activity (Siegel, 1990; Serpell, 1991; Edney, 1995; Brown and Rhodes, 2006),

as dog owners walk significantly more than non-dog owners (Serpell, 1991; Brown and Rhodes,

2006). In a qualitative study, a homeless youth expressed that owning a dog got them up for

exercise, which made them feel healthier (Rew, 2000).

Not all research has found a positive association between pet ownership and health benefits. A

study conducted on 60-64 year olds in Australia found that pet owners/carers were significantly

more depressive, had worse physical health, and were more likely to use pain relief medication

than non-pet owners/carers (Parslow et al., 2005). The pet owners/carers also had higher levels

of psychoticism than non-pet owners/carers. Participation was based on whomever was the

primary carer of the animal and not on pet attachment (Parslow et al., 2005). In Australia,

Parslow and Jorm (2003) conducted a cross-sectional study on pet ownership and cardiovascular

disease using a random sample of participants from two age groups, 40-44 years old and 60-64

years old. The authors’ found that pet owners had higher diastolic blood pressure, BMI and

7

increased risk of smoking than non-pet owners. As the study was cross-sectional, a temporal

pattern could not be determined. The authors’ suggested that the increased health risk could be

linked to the different levels of hypertensive risk factors (weight, alcohol consumption, smoking

and physical activity) that are indirectly associated with pet ownership (Parslow and Jorm,

2003).

Domesticated animals are not seen to be companion animals by everyone. A number of

individuals consider domesticated animals to be nuisances, especially free roaming animals

(Fielding and Mather, 2001). Free roaming and feral colonies can cause many public health and

ecological issues including predation on native species, the spread of disease, and attacks on

humans. Slater (2008) investigated public perceptions of free roaming dogs and cats in Italy, and

90% of respondents said they were an issue. A study conducted in the Bahamas investigating

complaints on free roaming and feral companion animal populations found that 88% of

Bahamians thought stray dogs were a nuisance and were worried about disease (Fielding and

Mather, 2001). In El Paso, Texas, 97% of households reported free roaming dogs were an issue

and 84% of households were worried about their own safety (Poss and Bader, 2007). Gunther et

al., (2015) conducted a study concerning the number of free-roaming cat complaints filed in five

cities in Israel during 2007 to 2011. In those years, a total of 101,415 complaints were reported

which included carcasses (55%), cat injuries (16%), kittens (11%), cats invading buildings

(10%), parturition (5%) and cat aggression towards humans (3%). The authors believed that

aggression and cats invading buildings could present public health hazards (Gunther et al.,

2015). Incidents of aggression have also been reported for free roaming dogs with attacks

occurring more frequently among youth under 20 years old (Sriaroon, 2006; Farnworth et al.,

2012; Lone et al., 2014; Jain and Jain, 2014). Dog attacks have been shown in a study to lead to

8

an increase in anxiety disorders of children in Kashmir, India (Lone et al., 2014). In addition,

more than 99% of human rabies cases are transmitted from dogs (with canine rabies being most

prominent in developing countries) (WHO, 1992), and dog attacks can lead to human deaths

either due to the transfer of rabies or due to the severity of the attack. Despite the many benefits

that owning companion animals can provide humans, free roaming companion animals have the

ability to severely impact human health and safety.

1.1.3. Stakeholders

Due to the difference in how companion animals are viewed and the impacts they can have,

many different stakeholders are interested in companion animal population dynamics including

animal welfare professionals, ecologists/conservationists, and public health professionals. A

study conducted in Hawaii, in 2011, involved the distribution of a survey to stakeholders

(n=5,407) to determine their perceptions on how feral cat colonies should be controlled (Lohr

and Lepczyk, 2014). The survey responses on cat colony control indicated that 78.2% of all

respondents believed cats should be removed permanently (i.e. euthanized) from areas with

threatened or endangered fauna (Lohr and Lepczyk, 2014). When these results were further

refined, accounting for stakeholders’ perspectives, almost all conservationists (98.1%) agreed

cats should be euthanized, while only 35.5% of animal welfare professionals believed euthanasia

was necessary, with 41.1% stating relocation was the best answer. Similarly, cat colony feeders

responded with 43.5% for euthanasia and 35.1% for relocation (Lohr and Lepczyk, 2014). The

American Veterinary Medicine Association’s (AVMA) Committee on Environmental Issues

(CEI) stated that maintenance of free roaming colonies through trap neuter release (TNR) does

not stop the predation on native species including birds and small mammals and does not

improve cats’ suffering (Barrows, 2004). They also support humane elimination of feral cat

9

colonies and laws that keep cats indoors and prevent the feeding of feral cat colonies (Barrows,

2004). An opinion piece of environmental conservationists against TNR expressed the belief that

euthanasia is more humane than allowing cats to live in poor health conditions. The authors

stated TNR allowed cats to return to these poor living conditions and likened it to “cat hoarding

without walls”. The authors then further stated that if animal welfare professionals are against cat

hoarding they should not support TNR (Lepczyk et al., 2010).

A study comparing stakeholders’ views (TNR groups, Audubon groups

(conservationists/ecologists) and the general public) on free roaming cats and the control

practices that should be used, found that TNR group members supported TNR (77%) and that

many of the TNR members did not support the implementation of long-term no kill shelters

(18% of TNR members supported long-term no kill shelters) (Wald, 2012). TNR group members

did not believe that cats kill wildlife and believed that cats should have access to outdoors.

Compared to Audubon group members and the general public, TNR group members had

significantly more positive feelings towards outdoor cats (Wald, 2012). In contrast, the Audubon

group members supported cat confinement and believed that cats competed with wildlife and

spread disease to wildlife. Most of the Audubon members supported TNR (49%). Compared to

members of TNR groups and the general public, a higher percentage of Audubon group members

supported the implementation of no kill shelters. As well as, a higher percentage of Audubon

group members supported trapping and euthanizing compared to TNR members and the general

public (Wald, 2012).

Although public health professionals are stakeholders in companion animal population

dynamics, their position is not as prominently evident in the literature on the topic of free-

roaming companion animals. However, several studies have investigated the role companion

10

animals play in the spread of zoonotic diseases (Kamoltham et al., 2003; Chomel, et al., 2006;

Macpherson, C.N.L., 2013; Dabritz and Conrad, 2010). Stakeholders have very different views

on companion animal population dynamics. As a result, achieving collaboration and determining

control methods that will please all interested parties and lead to successful control of free

roaming and unwanted companion animals is challenging.

1.1.4. International Scope

Location can affect companion animal population dynamics. Different areas around the world

face different societal problems. Understanding companion animal population dynamics is of

international interest, as a result control practices of free roaming and unwanted companion

animals need to consider country specific factors. Described below are some studies to

contextualize and consider this topic within its international scope.

1.1.4.1. Values

Different cultures and cultural values around the world result in different ownership practices,

and considerations concerning management of population dynamics of free roaming companion

animals. In the Bahamas, there are purebred dogs and potcakes (local mongrels), and their

perceived value is different (Fielding and Mather, 2001; Fielding, 2010a; Fielding, 2010b). A

study conducted by Fielding (2010a) on female dogs that had been bred (during the year prior)

found that purebreds were more likely to be kept inside or in an enclosure, and owners were

more likely to breed purebred dogs on purpose for the sale of puppies compared to potcakes.

Owners of purebred dogs were also more likely to plan on rebreeding their dogs compared to

potcake owners (Fielding, 2010a). Potcakes are often considered of no value (Fielding and

Mather, 2001; Fielding, 2010a; Fielding, 2010b), and although they are more likely to roam

11

freely (Fielding, 2010a), it has been suggested that they contribute less to population dynamics

because they are more likely to be spayed or neutered compared to purebreds (Fielding, 2010b).

A telephone survey conducted in Taiwan by Hsu, Severinghaus and Serpell (2003) determined

that Taiwanese individuals are less likely to pay for a dog from a pet store and more likely to

acquire a stray dog from the street. Taiwanese dogs are almost as likely to be obtained for

security/guarding purposes (47.3%) or fun (45.6%) as for companionship (41%) (Hsu,

Severinghaus and Serpell, 2003) unlike the United States and the U.K. where the majority of

owners view their pets as friends and family members (McNicholas et al., 2005; Walsh, 2009a).

The reason for obtaining a dog in Taiwan also affected how the dog was housed; it is common

practice to keep dogs obtained as guard dogs indoors and confined, while dogs kept for

companionship were kept indoors but unconfined. Further, individuals who were found to have

obtained a dog because they felt bad for the animal were more likely to keep the dog outdoors

(Hsu, Severinghaus and Serpell, 2003). The authors’ believed that the human-animal bond in

Taiwan is less prevalent than in Western countries. Yet, Taiwan’s cultural and religious beliefs

discourage euthanasia of unwanted animals (Hsu, Severinghaus and Serpell, 2003) adding

another cultural dimension to population dynamics.

1.1.4.2. Laws

Laws have been implemented around the world to help combat free roaming and unwanted

companion animals. Certain laws have been established that reflect the country’s societal values.

The Czech Republic has a law that states euthanasia of stray animals is only allowed in

conditions that would impose permanent suffering such as weakness, terminal illness, serious

injury, genetic or congenital defect, overall exhaustion, or old age (Voslářá and Passantino,

2012). Similarly, Italy has a no kill policy that has been in place since 1991 (Natoli et al., 2006;

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Voslářá and Passantino, 2012). Voslářá and Passantino (2012) further explained Italy’s law

stating that a captured dog or cat cannot be killed unless they are “seriously or incurably ill or

proven to be dangerous.” The Czech Republic and Italy implemented these laws as part of a

treaty that 22 European countries signed called the European Convention for the Protection of

Pets. This treaty aimed to improve animal welfare and reduce the number of stray animals.

Despite the implementation of these laws, animals are still being abandoned in the Czech

Republic, and in Italy there are still concerns regarding human health, animal welfare and social

costs associated with free roaming and unwanted companion animals (Voslářá and Passantino,

2012). The authors stated that these laws will not change the situation alone, public education on

responsible ownership practices needs to be included. Voslářá and Passantino (2012) further

stated cultures and cultural values need to be consider when implementing laws around

companion animal control. In Hawaii, California and Florida, it is illegal to abandon animals

and feed stray animals (Winter, 2004). In addition, unlike the European countries noted above,

in North America, there are at least two types of shelters, no kill and traditional. No kill shelters

only euthanize for behavioural and medical reasons (THS, 2013), while traditional shelters are

able to euthanize healthy surrendered animals for capacity reasons alone (CFHS, 2015a). For

stray or free roaming animals traditional shelters cannot euthanize until the mandatory holding

time (determined by the municipal code) lapses to aid in the return of lost animals to their

owners. For example, according to the Toronto municipal code, the largest city in Canada, a dog

at large that is seized and is not redeemed after 5 days becomes property of the city and the city

can choose to have the dog euthanized (City of Toronto, 2013).

1.1.4.3. Socio-Economics

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Samoa has one of the highest reported rates of ownership of dogs in the world at 88% of

households (Farnworth et al., 2012). Farnworth et al. (2012) interviewed 327 inhabitants of

Samoa to determine their attitudes towards free roaming dogs; 75% of respondents believed dogs

are important to Samoa, yet only 16% had received any education about dogs. The results

indicated 46% of respondents believed female dogs should go through at least one litter. Despite

56% of respondents stating that it is important to sterilize their dogs, the sterilization rate is only

19% (Farnworth et al., 2012). Veterinary care is limited in Samoa and 52% of respondents

reported cost was a factor in their decision whether or not to sterilize their dog(s) (Farnworth et

al., 2012). Haiti also suffers from a large population of dogs, similar to Samoa, and its low

neutering rate is likely due to limited access to veterinary care and the cost of neutering (Fielding

et al., 2012). A study conducted in Israel investigating cat owner’s attitudes and behaviour

towards free roaming cats sent out a questionnaire. The results indicated that respondents from a

lower than average income bracket believed neutering to be cruel compared to respondents in the

above average income bracket (Finkler and Terkel, 2012). This study also found that respondents

with a lower education level were significantly more likely to believe free roaming cats were not

an issue and more likely to feed them compared to individuals of a higher education level

(Finkler and Terkel, 2012). Furthermore, a study conducted in Nigeria found that the proportion

of respondents that confined their dogs and castrated them differed between literacy levels. The

results indicated that 100% of illiterate (n=103), 88.5% of semi-illiterate (n=96) and 79.6% of

literate (n=59) respondents did not confine their dogs, and 61.1% of illiterate, 87.5% of semi-

illiterate and 98.3% of literate respondents castrated their dogs (Eze and Eze, 2002). Moreover, a

Canadian study conducted on free roaming cats by Flockhart, Norris and Coe (2016) found that

as median income increased the free roaming cat density decreased. It was suggested that income

14

level therefore impacts sterilization rate, number of owned cats and cats’ access to outdoors

(Flockhart, Norris and Coe, 2016).

1.1.4.4. Climate

Temperature can also have an impact on the population dynamics of free roaming companion

animals. Colder climates are associated with decreased survival of free roaming cats and a

decrease in the number of estrus cycles a cat has per year (Gunther and Terkel, 2002). One study

inferred that the temperate climate in Tel Aviv, Israel allows for cats to achieve their maximum

reproductive rates in cats (Finkler and Terkel, 2012). Lohr, Cox and Lepczyk (2012) reached a

similar conclusion stating that Hawaii’s free roaming cat issue may be due to its tropical climate.

A study conducted on stray dogs in the tropics found that female dogs were able to ovulate and

exhibit estrus all year round, yet in months with high temperatures and humidity the frequency of

estrus decreased (Ortega-Pacheco et al., 2007).

There are many factors to consider when addressing companion animal population dynamics,

and not every country views free roaming and unwanted companion animals in the same way.

Before implementing a control practice, the public’s beliefs, attitudes and ownership practices

need to be taken into account, as well as environmental and socioeconomic factors for a program

to be successful.

1.1.5. Control Practices

Control practices play an important role in companion animal population dynamics, many

different practices have been implemented to control free roaming (owned and unowned) and

unwanted companion animals. Control practices are implemented depending on the outcome of

interest, which can vary between stakeholders. Overall, it is evident that the literature does not

15

support the use of one particular control practice and suggests combinations of control practices

may be more successful.

1.1.5.1. Spay and Neuter

Spay and neuter is one of the most common control methods used for reproduction control, and

is implemented in a variety of ways. Surgically removing the gonads (i.e., spay and neuter) is the

most successful method to prevent pregnancy in dogs and cats (Olson et al., 1986; Anderson,

1992). It is believed that spaying and neutering also has a variety of health benefits (e.g., reduced

chance of uterine disease and androgen-dependent diseases) (Olson et al., 1986; Anderson, 1992)

and results in behavioural changes (e.g., less aggression and less roaming) (Olson et al., 1986;

Root Kustritz, 2012). Historically for an owned pet, it has been recommended that the animal is

spayed or neutered at approximately 6 months of age (Olson et al., 1986). To get animals out of

shelters as quickly as possible and to combat unwanted pregnancies, early age (also known as

pre-pubertal or pediatric) spaying and neutering has been more recently introduced (Olson, Root

Kustritz and Johnston, 2001; Bushby, 2012). Early age spaying and neutering generally occurs

between 6 to 14 weeks of age and before the animal goes through puberty (Stubbs and

Bloomberg, 1995). There is a lot of disagreement in the literature as to whether early spaying and

neutering is safe. A study conducted by Spain et al. (2004) on the medical and behavioural

conditions of 1,659 adopted dogs that were spayed or neutered at either an early age or the

traditional age, found an increased rate of cystitis, hip dysplasia and urinary incontinence, and a

decreased rate of overweight body scores in the dogs that received early aged spaying and

neutering (Spain et al., 2004). In the study, dogs’ spayed or neutered early in life also showed an

increased incidence of developing noise phobias and sexual behaviours, and a decreased

incidence of escaping behaviours, urination in the house and separation anxiety (Spain et al.,

16

2004). Other behaviours affected by early age spaying and neutering were sex specific, with

early-age neutered males showing increased aggression, a greater probability of barking at

strangers or visitors, and excessive barking in general (Spain et al., 2004). Another study

comparing traditional spay and neuter to early spay and neuter, in which all dogs were followed

for 4 years, found that early spay and neuter did not increase behavioural problems, but early

spay and neuter were associated with higher incidences of infectious diseases (parvoviral

enteritis and upper respiratory infections)(Howe et al., 2001). The study also found no increased

incidence of hip dysplasia, musculoskeletal disorders, urinary incontinence and less

gastrointestinal problems (Howe et al., 2001). Although these results are contrary to the previous

study, Spain et al. (2004) speculated the increase in hip dysplasia may not warrant much concern

since it was reported based on signs such as arthritis, and some dogs were diagnosed at an early

age when this diagnosis is often unreliable. Further, despite the increase in cystitis reported, no

more than 2 episodes were reported for females that underwent early age spaying suggesting

long-term effects are unlikely (Spain et al., 2004). This could explain some of the differences in

the results found between the two studies. Obesity was also not found to be associated with early

spaying and neutering in the study by Howe et al. (2001), however it relied on the owner’s

perception of their dog being overweight, which may not be reliable (Howe et al., 2001).

Similarly among cats, two separate studies have found no behavioural differences (Stubbs et al.,

1996; Porters et al., 2014a) and no body weight composition differences as well as normal

skeletal development (Stubbs et al., 1996) between early aged and traditional aged spays and

neuters. Howe et al. (2000) conducted a long term study comparing the effects of early spay and

neuter (less than 24 weeks of age, N=188) to traditional spay and neuter (at 24 weeks of age or

older, N=75) in shelter cats. The results indicated that there was no difference in incidences of

17

infectious diseases (feline leukemia, feline immunodeficiency virus, viral enteritis, feline

infectious peritonitis and spirochetes causing diarrhea or upper respiratory infections), as well as

no differences in gastrointestinal, musculoskeletal and cardiopulmonary problems between cats

sterilized at an early or traditional age. There were also no differences in incidences of

destructive behaviour, inappropriate elimination and other behaviour problems (Howe et al.,

2000). Howe et al. (2000) found that cats sterilized at the traditional age had higher incidences of

urinary problems compared to cats sterilized early in life.

Early spay and neuter programs remain controversial. A commentary written by Bushby (2012)

stated that many American veterinarians are against early spays and neuters. However, it was

also stated that despite the opposition towards early spays and neuters, many American

veterinarians acknowledge that they are “easier, faster, and result in quicker recoveries”

(Bushby, 2012). Porters et al.’s (2014b) study offers support toward this belief. In this study

kittens, were spayed and neutered at either an early age (8-12 weeks) or the traditional age (6-8

months), and surgical times were significantly shorter for early spays and neuters compared to

traditional (Porters et al., 2014b).

1.1.5.2. Trap Neuter Release (TNR)

TNR is another type of control practice that has been implemented to control free roaming and

feral colonies of companion animals. Studies conducted on TNR have produced mixed results on

whether this type of program works. A study conducted in Florida on feral cats found that

although the original population size decreased with TNR, animals being abandoned or other

stray cats being attracted to food provisions counteracted the effect by replacing the cats that had

died or migrated out of the population after TNR (Castillo and Clarke, 2003). A theoretical

18

model conducted based on the Feral Cat Coalition trapping data across San Diego County,

California (1992-2003) and the Operation Catnip Inc. trapping data in Alachua County, Florida

(1998-2004) by Foley et al. (2005) found similar results in that the model indicated TNR did not

reduce the feral cat population size or decrease the number of females becoming pregnant. In

another study, Zaunbrecher and Smith (1993) suggested that neutering is an alternative to

eradication programs. The authors conducted a TNR program on a population of 41 feral cats.

During the 36 months follow-up period after the TNR program was initiated no kittens were

born, the health of the colony improved and there was a low turnover rate with a final population

of 36 cats at the end of the follow-up period (Zaunbrecher and Smith, 1993). Also during the

study period 10 cats died or went missing, but six new cats were added to the colony during the

last 18 months; the authors speculated that migration and abandonment of the cats could explain

the addition, but believed abandonment was more likely (Zaunbrecher and Smith, 1993). In

comparison, a study by Levy et al. (2003b) found that TNR can lead to long term reduction of

free roaming cats. The organization Friends of Campus Cats implemented a trap, neuter and

return program at the University of Central Florida from 1991 to 1996 (Levy et al., 2003b).

There were originally 155 cats in the colony and after adoption, euthanasia, deaths and

disappearances by 1996 there were 68 cats left (Levy et al., 2003b). The study continued for

another six years and by the end there were only 23 cats left in the colony (Levy et al., 2003b).

Levy et al. (2003b) stated no kittens were seen after 1995 and any new cats to the colony (either

stray or abandoned) were sterilized. Construction on the University campus is common and can

affect cat habitats (Levy et al., 2003b), which could have limited the number of cats living on or

immigrating to campus explaining to the success of this TNR program. Levy et al. (2003b) also

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included an adoption program for the socialized cats, which increased the rate of decline of the

population.

1.1.5.3. Non-Surgical Contraception

More recently, non-surgical contraception methods have become popular as a method to control

unowned free roaming companion animals. Many different types have been designed and tested

in labs since the year 2000, however, not all have been approved for broader use.

Immunocontraception is a form of non-surgical contraception with research being focused on

two main types: gonadotropin-releasing hormone (GnRH) and zona pellucida (ZP). Research

conducted on ZP has found mixed results among species, ZP as an immoncontraceptive shows

promise in dogs, yet has not been successful in controlling reproduction in cats. Levy et al.

(2005) tested porcine ZP (pZP) vaccines on fifteen cats and completed a breeding trial, all cats

became pregnant proving the vaccine to be ineffective. Similarly, a study conducted on SpayVac,

a pZP vaccine, found that all cats showed signs of estrus and it did not have an effect on the

number of kittens born (Gorman et al., 2002). Results showed that the vaccine did not interact

with the targeted tissues and did not produce a titer in the cats (Gorman et al., 2002). Another

study testing different feline ZP sub-unit vaccines, instead of pZP, found an increase in

unsuccessful pregnancies in the ZPA-DNA vaccine and in the ZPB+C DNA vaccine, but the

study had a small sample size (n = 7 and n = 5, respectively) and the results were not statistically

significant (Eade, Robertson and James, 2009). Research has shown that dogs do react to either

crude or pure pZP (Mahi-Brown et al., 1985). The study conducted by Mahi-Brown et al. (1985)

found that female dogs vaccinated with pZP became infertile when the vaccine was combined

with an adjuvant. The authors do suggest that caution should be applied as the immunization also

caused steroid changes leading to abnormal estrus cycles and the authors could not explain the

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mechanism behind these changes (Mahi-Brown et al., 1985). In a more recent study, four female

dogs were immunized using E. coli expressing recombinant dog ZP3-DT, the results of which

indicated fertility was blocked, however the dogs were injected 6 to 7 times over a span of a year

to achieve vaccine efficacy (Srivastava et al., 2002). Applying this in a practical situation would

be difficult as recapturing a feral dog or keeping a feral dog for a year period is unfeasible.

GnRH is a hormone that has been researched for immunocontraception methods as well.

Samoylov et al. (2012) conducted an experimental study in mice using dog and cat anti-GnRH

sera to determine if commercial phage-GnRH peptide conjugates could stimulate an immune

response. The researchers observed that anti-GnRH antibodies were created. This immune

response caused sterility by neutralizing antibodies, suggesting potential use for feral population

control (Samoylov et al., 2012). As this study was conducted in mice, further studies on dogs and

cats need to be conducted to validate these results in the target species. Levy et al. (2011)

completed an experimental study to test a synthetic GnRH peptide vaccine, GonaconTM (United

States Department of Agriculture, Animal and Plant Health Inspection Service, Wildlife

Services, National Wildlife Research Centre, Fort Collins, CO, USA), on female cats; all cats

vaccinated with the GonaconTM became infertile for 5 months to 5 years with 93% of the cats

remaining infertile for the first year. They also found that the cats who regained their fertility

during the study period and were bred had smaller litters compared to the control group. Levy et

al. (2004) also conducted an earlier study on male cats testing 3 different quantities of GnRH

vaccines against a control group. Within each of these 3 groups, some cats developed low

antibody titres and some cats developed high titres. Levy et al. (2004) suggested that cats that

developed low titres may not be completely suppressed and remain fertile. Unfortunately, a

breeding trial was not conducted and a relatively short follow up period of six months was used

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(Levy et al. 2004). As a result, infertility was not verified and it was not determined if GnRH

vaccines would be effective for long-term fertility control in male cats.

The first study investigating the GnRH vaccine (GonaConTM) in female dogs was conducted in

2009 by Bender et al., with another conducted by Vargas-Pino et al. in 2013. Both studies

investigated the administration of injecting the GnRH immunocontraceptive vaccine at the same

time as the rabies vaccine. Similar results were found in both studies showing that concurrent

administration of the vaccines had no effect on the efficacy of either, although both studies found

GonaConTM to be an effective contraceptive, but the researchers suggested more research still

needs to be completed on GonaConTM (Bender et al., 2009; Vargas-Pino et al., 2013). The

literature has indicated that GnRH vaccines show promise as a non-surgical method to control

both free roaming dogs and cats.

In addition to GnRH vaccines, the GnRH agonist deslorelin has been tested as an implant for

long-term reproduction control. Researchers implanted cats (10 controls and 10 with a 6mg

deslorelin implant) with results showing that the treatment group had significantly lower

oestradial levels over a 13 month period, excluding the first month after treatment, yet length of

suppression of folliculogenesis varied, ranging from 4 to 14 months (Munson et al., 2001).

Deslorelin has also been tested in dog populations investigating its ability to delay puberty.

Implantation occurred in 8 dogs at 4 months of age with either 4.7 mg or 9.4 mg of GnRH

agonist deslorelin and puberty was delayed for 2 years and in excess of 2 years, respectively

(Sirivaidyapong, Mehl and Trigg, 2012). A larger study conducted in Australia using 30 male

and 52 female dogs also tested the impact of deslorelin implants (Trigg et al., 2001). Animals

were assigned to four different groups: 3 mg, 6 mg, 12 mg and a control group. Results showed

suppressed reproductive function for both males and females treated with these implants. For

22

males, the effect was dose-dependent with a minimum of 12-month suppression, whereas for

females, suppression lasted up to 27 months and was effective at any stage of the estrus cycle

(Trigg et al., 2001). The results above suggest that implantation of GnRH agonist deslorelin is a

promising non-surgical form of contraception for companion animal populations. Further

development of deslorelin is needed to examine its impact on free roaming cats and dogs.

1.1.5.4. Euthanasia

Euthanasia as a control practice appears to results in a great deal of concern and controversy

among different stakeholders. A model generated by Schmidt et al. (2009) found that euthanasia

rates need to be 75% or higher to account for immigration and to keep population sizes below

initial levels. The model tested three different interventions: euthanasia alone, TNR alone and a

combination of TNR and euthanasia, each at three different treatment rates, 25%, 50% or 75%.

The model also accounted for immigration rates of either 0%, 25% or 50% which was applied to

each intervention at each treatment level. From this model, the authors concluded that euthanasia

alone, at any treatment rate when accounting for immigration rates of either 0%, 25% or 50%

leads to higher population declines compared to TNR alone or compared to a combination

approach of TNR and euthanasia (except for a treatment rate of 25% combined with a 50%

immigration rate) (Schmidt et al., 2009). A large portion of the primary research on euthanasia as

a population control strategy has investigated eradication programs on islands overrun with feral

cats (Twyford et al., 2000; Bester et al., 2002; Algar, Burbidge and Angus, 2002; Ratcliffe et al.,

2010 ; Ramsey et al., 2011; Algar, Angus and Onus, 2011; Robinson and Copson, 2012).

Various island-based eradication programs have been attempted with varying results. Marion

Island, an island of South Africa located in the Southern Indian Ocean, successfully eradicated

feral cats using a 7 phase program over a 19 year period (Bester et al., 2002). Marion Island is

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29,000 hectors consisting of montane and coastal regions and has an average temperature of 5oC

and an average precipitation of 2576 mm in the form of rain, sleet and snow. It was estimated

that 2139 cats lived on Marion Island (Bester et al., 2002). The first two phases of the eradication

program on Marion Island included obtaining information about the cat population, and

determining the utility of using various pathogens for biological control. The last five phases

included biological control, hunting, trapping and poisoning as well as studies to determine the

effectiveness of each control method. Eradication of feral cats on Hermite Island which is

located off the coast of Western Australia, was complete in a matter of weeks, using a trap and

bait program (Algar, Burbridge and Angus, 2002). Hermite Island is 1,020 hectors with sandy

beaches, areas of mangroves, cliffs and limestone ridges and peninsulas and had a population of

at least 20 cats (Algar, Burbridge and Angus, 2002). Whereas, the eradication program on

Macquarie Island (an island of Australia located in the southwest Pacific Ocean) which included

trapping, shooting, gassing, and baiting, took 5 years to complete (Robinson and Copson, 2013).

Macquarie Island is larger at 12,800 hectors and had a population of 761 cats (Robinson and

Copson, 2013). Algar, Burbridge and Angus (2002) stated that eradication on Hermite Island was

fast and their results cannot be compared to other studies as temperature, size and shape of the

island, and prey all play a role in the effectiveness of an eradication program. Researchers have

demonstrated euthanasia can be a successful method of eradication for feral populations,

particularly in closed populations.

1.1.5.5. Other Control Practices

Other population control practices have been studied to a limited extent including education and

legislation. There is little research on the effect of educational programs as a control practice to

manage companion animal populations. In Sri Lanka, research examined knowledge, attitude and

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practice (KAP) scores to assess the impact of knowledge on pet ownership, pet care and rabies

(Matibag et al., 2009). KAP scores improved after reading the information and education

campaign (IEC) material, owners knew more about rabies, and owners started to register their

pets and build shelters for them. However, following the campaign, an increase was found in the

number of owners that would allow their dogs to roam unsupervised (Matibag et al., 2009). This

increase in the willingness of owners to allow their dogs to roam freely may have occurred as a

result of educational material misleading owners to believe that following rabies vaccinations it

was safe to allow their dogs to roam (Matibag et al., 2009). In another study, researchers in

Taiwan recruited 15 veterinary clinics to be part of a randomized control study to see the effect

of educational material on ownership practices (Weng et al., 2006). Owners found the material

useful, with 84.6% of the intervention group during the first three months indicating they used

the material to help care for their pet(s). However, the educational material was found to have no

effect on owners’ decisions whether to spay or neuter their dogs. The authors believed this could

be due to the strong beliefs the Taiwanese have on dog reproduction including the belief that

dogs should be sterilized post-puberty and female dogs should have at least one litter before

being spayed (Weng et al., 2006). Interestingly in this study, during the first 4 months of

ownership, the intervention group had an increased rate of relinquishment compared to the

control group. This trend reversed after the first 4 months of ownership. The authors’ suggested

that the educational material on behaviour may have increased the owner’s ability to recognize

behavioural problems leading to the increased relinquishment in the first four months (Weng et

al., 2006). The authors’ also acknowledged certain limitations of their study including

convenience sampling, and limiting the generalizability of the study (Weng et al., 2006). In

addition, the sample size was relatively small (N = 126), suggesting the possibility of insufficient

25

power to detect the effects of the intervention (Weng et al., 2006). Education is an important

tool that can be used to inform the public on better ownership practices. Future research into the

effects of education efforts is warranted including the accompaniment with other control

methods.

1.1.6. Shelter Management

One consequence of companion animal population dynamics is unwanted companion animals,

which can lead to overcrowded shelters. Animals enter shelters worldwide, and without the space

to hold the healthy, adoptable animals, they can be euthanized (Kass, 2007). Wenstrup and

Dowidchul (1999) conducted a survey in the summer of 1998 of 186 shelters and animal control

facilities in the United States to collect shelter data. The authors reported that in total, shelters

only had the capacity to house 2.6% of the animals that entered the shelters during the previous

year. A combined total of 764,879 animals went through the shelter with only 19,998 kennels to

house them. In total, 59% of the animals that entered these shelters were euthanized, and 34% of

euthanasia were due to limited capacity (Wenstrup and Dowidchul, 1999). Wenstrup and

Dowidchul (1999) reported, that according to the shelters staff, 52% of the euthanized animals

were adoptable. These results are similar to a survey conducted in 1991, which reported on

intake and euthanasia data from Massachusetts, New Jersey and Washington shelters, with

60.7% of the animals that entered the shelter that year being euthanized (Rowan, 1992). In

Canada, a survey conducted on shelter trends in Canadian humane societies and Societies for the

Prevention of Cruelty to Animals (SPCAs) in 2014 reported that 11% of dogs admitted and 37%

of cats admitted were euthanized, of this 2% of dogs and 6% of cats were healthy when

euthanized (CFHS, 2015).

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Euthanizing mass numbers of healthy animals can also take an emotional toll on shelter

employees working in this environment (White and Shawhan, 1996; Gardner, 2008). This

phenomena called compassion fatigue, has been identified as a post-traumatic stress disorder

“due to exhaustion of compassion stressors” (Figley and Roop, 2006). The majority of research

on euthanasia as a traumatic stressor has been conducted in the United States. Research has

shown that euthanasia-related stress can lead shelter employees to feel depressed, suffer from

lack of sleep and nightmares, cause them to question their self-worth, and affect their personal

lives (White and Shawhan, 1996; Reeve et al., 2005). For example, when shelter workers were

asked to describe their feelings and thoughts about euthanasia, one individual stated “I entered

therapy in the beginning of June and am being medicated for severe depression. Much of my

anger, guilt, frustration, and outright sadness is connected to my work and my passion for

wanting to save animals I kill” (White and Shawhan, 1996). Reeve et al., (2005) reported that

44.4% of their participants (N=335), who were shelter workers, agreed euthanasia caused them

great stress, 29.6% agreed it made them feel depressed, 29.4% lost sleep and 23.5% had

nightmares. Individuals who were directly involved with euthanasia had higher stress and lower

job satisfaction levels (Reeve et al., 2005). Furthermore, a study found that as dog euthanasia

increased, shelter employee turnover increased (Rogelberg et al., 2007). The study did not find

the same relationship for cat euthanasia. This difference was explored further and the attachment

levels between shelter workers and dogs were found to be stronger than for cats (Rogelberg et

al., 2007). Results also indicated that if euthanasia was due to behavioural or health reasons,

employee turnover was less (Rogelberg et al., 2007).

Not every study supports the results of euthanasia-related traumatic experience among shelter

workers. Two studies found that only a few shelter workers experienced traumatic symptoms in

27

association with experiences working in a shelter (Rohlf and Bennett, 2005; Roberts, 2015). In

the one, a qualitative study (N=22), conducted by Roberts (2015), the trauma had to be directly

reported by the individual themselves in an effort to see if the shelter workers would talk about

their trauma symptoms on their own accord. Specific prompts about trauma symptoms were not

asked, only general coping prompts were used (Roberts, 2015). Many efforts have been made in

recent years to decrease the amount of euthanasia occurring in shelters; this may be another

explanation for the lack of trauma symptoms in shelters workers found by Roberts (2015). There

was also no use of standardized measurements to determine if an individual suffered from trauma

(Roberts, 2015). Although only one respondent reported a traumatic experience associated with

animal euthanasia within this study, the other 21 respondents reported euthanasia was a stressor

(Roberts, 2015). In both papers, by Rohlf and Bennett (2005) and Roberts (2015), the authors

suggested that the lack of trauma reported may be due to the resignation of the employees that

experienced trauma prior to the studies being conducted. Another explanation for these findings

could be the workers themselves; not every employee is affected by euthanasia to the same

degree as others (White and Shawhan, 1996; Reeves et al., 2005). One of the shelter employees

from the study conducted by White and Shawhan (1996) stated, “I have no feelings about

euthanasia. It doesn’t bother me. I’ve been at it too long.” Certain individuals experience and

deal with stress differently (Reeves et al., 2005), some employees pretend the euthanasia never

happened or do not allow themselves to become attached to the animals, while others use “sick

humour” or physical exercise to relieve stress (White and Shawhan, 1996).

Due to overcrowding, resulting in the euthanasia of healthy adoptable animals and health effects

on shelter workers, shelters have been changing their approach to managing shelter populations.

In recent years, Capacity for Care (C4C) shelter management has been recommended as a

28

solution to overcrowding in shelters. The idea of this management practice is to decrease the

number of animals in a shelter at one time and decrease their length of stay, ultimately increasing

the number of animals they help (Karsten, 2014). C4C aims to improve the welfare of animals in

shelters by using the following to provide the 5 freedoms as a standard: (1) Monitoring feed

intake by the pets to ensure the animals do not suffer from hunger and thirst, providing larger

housing facilities to ensure (2) the animals do not suffer from discomfort and, (3) allow to

express normal behaviours; (4) include a hiding spot to ensure the animals are free from fear and

distress; and (5) decrease disease through decreased overcrowding allowing the animals to be

free from pain, injury and disease (Karsten, 2014). According to the C4C model, the true

capacity of a shelter is calculated using the following parameters: the number of appropriate

housing units; staffing for programs or services; staff training; average length of stay; and the

total number of reclaims, adoptions, transfers, release, or other outcomes (Newbury et al., 2010).

One of the ultimate goals of C4C is to decrease the length of stay of each animal. To date, there

has been very little empirical research conducted on C4C management style comparing its

efficacy to other management styles or its potential effect on the size of stray and abandoned

companion animal population sizes, and stray intakes to shelters. The majority of information

informing the current understanding of C4C has been from case studies. Recent case studies

were conducted on the implementation of C4C at the Guelph Humane Society (Guelph HS) and

the Prince Edward Island Humane Society (PEI HS) (CFHS, 2015b). Information on shelter care

was compared before and after C4C was implemented at each shelter. Data were collected for the

same period of time a year apart (August 2013 – January 2014 pre-C4C and August 2014-

January 2015 post-C4C). Both shelters demonstrated a reduction in the number of cats entering

their sickbays and an increase in adoptions when comparing these two time periods. The PEI HS

29

had a reduction in average length of stay from 23.4 to 13.1 days while the Guelph HS maintained

their average length of stay of 6-7 days. Guelph HS showed a decrease in the number of cats

euthanized from 35 to 11 comparing these two time periods, while the PEI HS increased from 21

to 22 cats. It was noted that the PEI HS had a large number of diseased feral cats enter the shelter

following the period they implemented C4C, which increased their euthanasia number for the

following year. Both PEI HS and Guelph HS reported being impressed with the changes that

occurred due to implementing C4C (CFHS, 2015b). The Vancouver SPCA in British Columbia

(BC) also assessed the implementation of C4C. In this case, shelter data were collected in 2012

after C4C was implemented and was compared to 2011 shelter data before C4C was

implemented. Findings showed a 9% decrease in cat intake, length of stay (LOS) decreased from

40 days to 22 days, and the average number of cats in isolation went from 12 to 1 (Karsten,

2014). These case studies suggest that C4C has promising effects that could potentially decrease

euthanasia and length of stay of animals in shelters. As C4C uses the five freedoms to improve

animal welfare in the shelter, research investigating the health and welfare benefits of C4C is

needed to determine if the animal’s welfare is truly improved. Further research on a larger

sample size and accounting for multiple variables that may impact C4C needs to be conducted.

In addition, while C4C has shown improvement to the shelter management of unwanted

companion animals, it is not known the effects on companion-animal populations outside of the

shelter including the free roaming population and animals not accepted into a shelter system

because of capacity restrictions.

1.1.7. Characteristics of shelter animals being adopted or euthanized

Research has been conducted on characteristics of animals in shelters to determine factors

leading to relinquishment, euthanasia, and adoption. The majority of this research has been

30

conducted in the United States and no research at this time has been done in Canada. Research

has been conducted in both no kill (Diesel et al., 2007; Nĕmcová and Novák, 2003; Cannas et

al., 2014) and traditional shelters (Clevenger and Kass, 2003; DeLeeuw, 2010, Lepper, Kass and

Hart, 2002; Marston et al., 2004; Posage, Bartlett and Thomas, 1998). Understanding factors and

characteristics that affect an animal’s final disposition once in a shelter is important for

increasing positive outcomes for the animals. Adopter preferences for female dogs (Lepper, Kass

and Hart, 2002; Diesel, Smith and Pfeiffer, 2007; DeLeeuw, 2010; Davidson and Zueffle, 2013;

Cannas et al., 2014), puppies under a year of age (Lepper, Kass and Hart, 2002; Diesel, Smith

and Pfeiffer, 2007; DeLeeeuw, 2010; Brown, Davidson and Zueffle, 2013; Cannas et al., 2014),

purebreds (Lepper, Kass and Hart, 2002; Diesel, Smith and Pfeiffer, 2007; DeLeeuw, 2010;

Brown, Davidson and Zueffle, 2013) and small dogs (Posage, Bartlett and Thomas, 1998;

Lepper, Kass and Hart, 2002; Diesel, Smith and Pfeiffer, 2007; DeLeeuw, 2010; Protopopova et

al., 2014; Brown, Davidson and Zueffle, 2013; Cannas et al., 2014) have been reported. One

study completed in the Czech Republic found mixed breed puppies (2-4 months of age) were

more likely to be adopted compared to dogs with specific breed characteristics and there was no

preference for sex (Nĕmcová and Novák, 2003). Studies conducted in the United States on more

specific breed types found that giant companion dog breeds had a higher rate of being adopted

and guard dogs had a lower rate of being adopted (Lepper, Kass and Hart, 2002; Brown,

Davidson and Zueffle, 2013). In the U.K., a study found gundogs and utility dogs had higher

rates of adoption compared to hounds (Diesel, Smith and Pfeiffer, 2007), which was

contradictory to an American study where hounds had a greater adoption rate (DeLeeuw, 2010).

Understanding the role of breed in adoption is challenging; differences in adoption rates between

breeds could be due to country specific preferences or due to how each study combined the large

31

number of breed categories that exist as each study appears to use a slightly different

methodology. The literature has not identified a consistent trend relating to coat colour

preferences and adoption. Research in the U.K. shows that black and white coat coloured dogs

were the least preferred resulting in an increased length of stay (Diesel, Smith and Pfeiffer,

2007), whereas in the United States brindle or black and tan patterns have been associated with

decreased adoption (Lepper, Kass and Hart, 2002). Other studies in the Czech Republic and

United States showed coat colour had no measurable effect on length of stay (Brown, Davidson

and Zueffle, 2013; Protopopova, et al., 2014). Furthermore, studies investigating euthanasia

trends found black dogs (Posage. Bartlett and Thomas, 1998; DeLeeuw, 2010), adults (Clevenger

and Kass, 2003) and males (Martson, Bennett and Carson, 2004) were more likely to be

euthanized. These results follow the same trends as adoption, as animals with a decreased chance

of adoption have been shown to have an increased chance of euthanasia in traditional shelters.

Much research has been conducted on reasons for relinquishment (Coe et al., 2014), but few

studies have looked at how it affected the dog’s probability of being adopted. Researchers

investigating reasons for relinquishment and its effect on dog adoption found that dogs

surrendered due to owner-related reasons such as expense, moving and agency holds (animal is

in shelter due to owner being in jail or hospitalized) were adopted more frequently compared to

animals surrendered for behavioural reasons or health reasons (Lepper, Kass and Hart, 2002;

DeLeeuw, 2010)

A study conducted in Florida, United States focused on how behaviour impacted a dog’s length

of stay in Alachua County Animal Services from May to December, 2012. Dogs who stood still,

faced away from potential adopters, paced back and forth, or engaged in any contact with the

enclosure increased their length of stay by 5, 15, 15-20, and 30 days respectively (Protopopova et

32

al. 2014). Researchers have suggested that online photos of shelter animals can improve median

days to adoption (MDA) (Lampe and Witte, 2005). Researchers studying black labs in United

States shelters found that photos where the dog was making eye contact with the camera, where

the dog was standing, and photos taken outdoors all decreased the MDA (Lampe and Witte,

2005). Higher quality photos were also found to decrease the MDA.

Increased length of stay can have negative health impacts on the animals staying in the shelter.

Two studies conducted on cats found that cats who stayed longer than 6 days in a shelter had an

increased chance of getting an upper respiratory infection (URI) (Bannash and Foley, 2005;

Dinnage, Scarlett and Richards, 2009). Dinnage, Scarlett and Richards (2009) found that URI

was the top reason given for euthanasia, and kittens with URI’s were two times more likely to be

euthanized compared to healthy kittens. There is no literature at this time investigating how

length of stay impacts dogs’ health indicating an opportunity for further research.

Characteristics of cats in relation to adoption and euthanasia have also been investigated but less

frequently than those of dogs. According to the research, male cats were adopted more quickly

than females (Lepper, Kass and Hart, 2002; Brown and Morgan, 2015) and just like puppies,

kittens were preferred compared to adult cats (Lepper, Kass and Hart, 2002; Brown and Morgan,

2015). Coat colour also affected a cat’s length of stay, torbie (tortoiseshell cats with tabby

patterns) having the shortest and tuxedo having the longest stays. Exotic breeds spent less time in

the shelter compared to the common domestic shorthaired which spent the longest time in

shelters (Brown and Morgan, 2015).

1.1.8. Methodology

33

Knowledge synthesis is an important methodology to inform evidence-based decisions (Tricco,

Tetzlaff and Moher, 2011). It includes identifying, assessing and synthesizing all available

research evidence on a given topic using structured and transparent methods (Graham et al.,

2006). Scoping reviews are a commonly used knowledge synthesis method (Arksey and

O’Malley, 2005). They are conducted on broad topics with intricate research questions, which

tend to be policy driven (Arksey and O’Malley, 2005). Scoping reviews aim to provide a

description (characterization) of the relevant research. Unlike a systematic review, they usually

do not include a quality assessment of the research included (Arksey and O’Malley, 2005). There

are multiple purposes for conducting a scoping review: to identify the breadth and depth of the

research in a topic area, to summarize and describe the available research and determine research

gaps, and to determine if a systematic review meta-analysis (SR-MA) (another common

knowledge synthesis) can be conducted (Arksey and O’Malley, 2005). Scoping reviews follow a

systematic protocol that includes five stages. First is identifying the research question, second is

identifying available studies (search strategy), third is determining relevance, fourth is data

extraction and characterization, and last is reporting and summarizing the results (Arksey and

O’Malley, 2005).

1.2. Thesis Rationale

Understanding companion animal population dynamics is complex and is being considered by

many countries throughout the world. Due to this, different stakeholders are interested in this

topic, which has contributed to a vast amount of research and published information. The

resulting data are published in a variety of sources representing stakeholders invested in this

topic. Combining the existing knowledge on companion animal population dynamics in order to

determine the breadth and depth of the present research on this topic offers a valuable

34

opportunity to further stakeholders’ understanding of companion animal population dynamics.

Assimilating and summarizing the published research on companion animal population dynamics

will assist in identifying areas for more in-depth knowledge synthesis activities as well as gaps to

direct areas for future research. It is important to know what research has already been completed

to avoid unnecessary repetition, to determine the effectiveness of interventions, and to know

where future research should be targeted.

A common consequence of companion animal population dynamics is overcrowding in shelters.

Research on characteristics and factors that lead to adoption are important to help decrease

overcrowding. Currently, there is no research conducted on this topic in Canada. This research

could provide shelters with information to help identify which factors are under the direct control

of the shelter and which factors could be addressed via outreach to maximize successful

adoptions, minimize unnecessary euthanasia or returns, and decrease length of stay.

1.3. Thesis Objectives

The specific objectives of this thesis are:

1) To identify all published research up to May 2015 investigating approaches to

managing companion animal population dynamics to control the number of owned

free roaming, unowned free roaming, and unwanted companion animals (Chapter 2).

2) To determine which factors, based on individual dog characteristics, animal source

and shelter demographics, affected the time to adoption for dogs entering the BC

SPCA shelter system between January 2010 and July 2014 (Chapter 3).

35

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45

CHAPTER TWO

A Scoping Review of Published Research on the Population Dynamics and Control

Practices of Companion Animals

46

Abstract

Companion animal population dynamics is a global, diverse issue and can affect society in

multiple ways, including impacts on public health, environmental destruction and shelter

management. The purpose of this scoping review was to use structured and transparent methods

to identify all published research investigating companion animal population dynamics and/or

control practices. A comprehensive search strategy was implemented using five online databases

(i.e., PubMed, CAB Direct, Agricola, PsycINFO, and Scopus) and resulted in the identification

of 7,810 unique citations. These citations were screened for relevance by two independent

reviewers. Of these, 1,353 were initially deemed relevant. Full articles were procured and 869

articles (450 primary research and 419 reviews) were confirmed relevant and relevant data

extracted. Most of the included articles were published in the United States (364, 41.4%) and 217

articles (25%) were published between 2012 and 2015. The majority of the articles investigated

or discussed control practices (705, 80.2%), more specifically on different reproduction control

practices (552, 59.4%), and euthanasia (333, 37.9%) methods. This quantity of research in these

areas indicates an opportunity for systematic reviews and meta-analysis.

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Introduction

Companion animals, including dogs, cats, horses, and rabbits, are broadly present in today’s

society. In the United States, in 2012 there were approximately 70 million owned dogs and 74

million owned cats (AVMA, 2012). In the UK, in 2014 there were approximately 9 million dogs

and 7.9 million cats owned (PFMA, 2014), and in Canada, in 2011 approximately 5.9 million

and 7.9 million owned dogs and cats, respectively (CVMA, 2011). The owned companion

animal population is one component of determining the companion animal population size. Free

roaming and unwanted companion animals combined with owned populations create the total

population. Obtaining information on the unowned free roaming population can be difficult, but

some estimates indicate that this population may be as large as the owned population. For

example, according to the American Society of the Protection of Cruelty to Animals (ASPCA)

(2014), there are 70 million stray cats in the United States.

Many factors lead to the development of free roaming (owned and unowned) and unwanted

companion animal populations. One factor is different pet ownership practices: allowing pets to

roam freely that are sexually intact leads to unwanted litters and a lack of pet identification leads

to lost animals entering the shelter with no information to contact their owners. The unwanted

companion animal population is a result of abandonment and relinquishment, which can lead to

overcrowded shelters and larger stray or feral populations. Free roaming companion animals can

have many negative impacts on their surrounding environment. For example, if intact, they are

able to reproduce, creating larger populations potentially leading to an even greater impact. They

may spread disease to humans (Gerhold and Jessup, 2013) and other animals (Gerhold and

Jessup, 2013; Hollings et al., 2013). They may also attack humans (Mustiana et al., 2015;

Sudarshan et al., 2006) and other populations (e.g., birds, small mammals) (Hawkins, Grant and

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Longnecker, 1999; Butler, du Toit and Bingham, 2004). In addition, free roaming companion

animals may contract disease themselves (Butler, du Toit and Bingham, 2004; Daryani et al.,

2009; Zain et al., 2013) and can be the victim of an attack from another animal and suffer from

injury (Butler, du Toit and Bingham, 2004).

Due to the multitude of effects of companion animal population dynamics, it has implications for

many different stakeholders. There are three main groups of stakeholders: 1) animal welfare

professionals; 2) public health professionals; and 3) ecologists, conservationists and wildlife

managers, each approaching the management of homeless animals from different perspectives.

Animal welfare professionals often want to ensure free roaming and unwanted animals are

humanely and ethically treated (Hiby, 2010). Public health officials are interested in controlling

the spread of zoonotic diseases, preventing biting incidents and managing sanitation related to

free roaming companion animals (Ezeokoli and Umoh, 1987; Beck, 2012; Dalla Villa et al.,

2013). Lastly, ecologists, conservationist and wildlife managers are concerned about free

roaming animals’, particularly cats’, impact on populations of native animal species and their

destruction of native habitats (Lepczyk, Mertig and Liu, 2003; Ratcliffe et al., 2010; Duffy and

Capece, 2012).

Since each stakeholder has their own targets and outcomes of interest, different control practices

have been employed and researched. The public health community has investigated a

combination of vaccination and trap-neuter-release (TNR) programs (Reece, Chawla and Hiby,

2013; Roebling et al., 2014). Ecologists, conservations and wildlife managers often advocate and

use euthanasia to decrease populations of animals, which predate on native species (Algar et al.,

2011). Animal welfare professionals have employed a variety of different reproduction control

options including non-surgical and surgical approaches as well as legislation, education and

49

adoption programs (Olson and Moulton, 1993; Hiby, 2010; Greenberg et al., 2013). As a result

of the diverse interest in companion animal population dynamics, a wide variety of research has

been published on this topic, and this research has not been previously synthesized using a

formal and structured approach that provides more credible evidence for decision-making

(Tricco, Tetzlaff and Moher, 2011).

Scoping reviews are a structured and transparent knowledge synthesis method conducted on

broad topics that are often policy driven (Arksey and O’Malley, 2005). They can also be used as

the beginning step to identify areas for subsequent systematic review and meta-analysis (SR-

MA), as well as identify the research gaps (Arksey and O’Malley, 2005).

The purpose of the current study was to use scoping review methodology to map out and

characterize the breadth and depth of existing literature on approaches to managing companion

animal population dynamics on a global scale. Specifically, the objectives were to determine

well-investigated research areas, research gaps and potential areas suitable for SR-MAs. The

results have the potential to inform the direction of future research on companion animal

population dynamics and to inform policy decisions for invested stakeholders at the local,

national and or international level.

Methods

Review Protocol, Team, Question and Scope

The review was performed using an a priori protocol adapted from Coe et al. (2014). Ten

individuals with varying expertise on the topic (companion animal population dynamics),

epidemiology and research-synthesis activities comprised the review team. The review question

was “What is the current state of knowledge on approaches to managing companion animal

50

population dynamics to control the number of owned free-roaming, unowned free-roaming and

unwanted companion animals?” Primary research (quantitative or qualitative), reviews, and

commentaries investigating or discussing companion animal population dynamics were included.

A list of key definitions can be found in Table 2.1.

Search Strategy

An existing list of known relevant literature (n=42) obtained from unpublished data collected as

part of the scoping review by Coe et al. (2014) on companion-animal relinquishment was used to

create a comprehensive search strategy. Using an arrangement of multiple population terms (e.g.

canine, feline, companion animals, pets), exposure terms (e.g. homeless, abandon, unowned,

feral) and intervention terms (e.g., spay, neuter, animal control), database-specific search

strategies were created. The search strategy was applied to five bibliographic databases:

MEDLINE, Scopus, CAB Direct, PsycINFO and Agricola. Different combinations of these

terms were tested in each database: adding, subtracting and reorganizing terms to ensure that the

search was capturing all potentially relevant articles. To assess the inclusivity of the final search

strategy, the proportion of the original 42 articles captured by entering the search strategy into all

five databases was determined (39/42 =97.5%). The initial search was completed on December

10, 2013 (MEDLINE), December 11, 2013 (CAB Direct, Agricola, PsycINFO) and December

18, 2013 (Scopus). An updated search using the original population terms combined with the

terms “growth rate”, “lambda“ or “carrying capacity”, was completed on December 23, 2013

(Agricola, MEDLINE, PsycINFO), December 24, 2013 (CAB Direct) and December 27, 2013

(Scopus). The final specific database search strings are available in Appendix A. The initial

searches did not contain any filters confining them.

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In 2015, the most comprehensive searches were repeated to capture new articles published from

the time of the first searches. The repeated searches were performed in Medline, PyscINFO and

Scopus on May 28th, Agricola on May 29th and CABDirect on June 2nd of 2015. Medline,

CABDirect and Agricola had specific date restrictions that matched the last day the initial

searches were performed. Scopus and PsycINFO had year restrictions limiting the search from

2013 and onwards.

To assure the search was thorough, reference lists from two relevant book chapters, three

relevant literature reviews, 28 randomly selected relevant primary research articles (from the

2013 search) and a government document that included a list of citations on pet population

control articles, were hand searched for additional articles.

Relevance Screening

The relevance screening process began with an a priori designed form containing one key

question. The question examined whether or not the citation described population dynamics,

surveillance and/or control practices of free roaming (owned or unowned) and unwanted

companion animals. The form was reviewed by multiple independent stakeholders before being

used, and was pre-tested by four reviewers on 30 randomly selected abstracts. Relevance

screening advanced when a kappa agreement of 0.8 or greater was reached during pre-testing. At

this stage of reviewing, two individuals from the review team independently completed

relevance screening on the titles and abstracts of the identified citations. Disagreements were

resolved by consensus between the reviewing pair, if an agreement could not be made a third-

reviewer was brought in to resolve it. The final relevance screening form can be found in

Appendix A. Citations that focused solely on vaccination to control disease of free roaming and

unwanted companion animals were excluded as the interest of this review was control practices

52

that directly, controlled population size. All languages were kept at this stage. If the citations fit

the inclusion criteria it moved forward to the next stage of article procurement, data

characterization and extraction (DCE).

Article Procurement

To obtain copies of the full articles, titles, authors and journal or book titles were searched in the

University of Guelph’s database, Primo. If full copies of the articles could not be directly

obtained from Primo, a copy of the journal was requested through the University of Guelph

Annex. Articles not available through the University were requested through Interlibrary Loans

from other Universities. If the article was not available through these approaches, a Google

search was conducted for the full article. At this stage all outstanding citations were sent to a

team of librarians at the University of Guelph, the team of librarians conducted their own search

and provided information to the research team on how the full articles could be obtained. At this

stage, articles that remained missing were checked to determine the language they were

published in. If not published in English or Spanish, they were removed from the study due to

limited resources to review articles in other languages. Articles that were missing but published

in English or Spanish were searched to determine if the authors’ email could be obtained for a

copy of the article. If this could not be found, the article was removed from the study.

Data Characterization and Extraction (DCE)

The DCE process involved an a priori form, five stakeholders and two academics with content

expertise were invited to provide feedback on the DCE form and to ensure the form was

inclusive prior to use. The stakeholders were individuals’ who held positions with either the

Canadian Federation of Humane Societies (CFHS); the Society for Prevention of Cruelty to

53

Animals (in British Colombia or Ontario); or the Toronto Feral Cat program. One academic who

provided feedback, known for their research in the area of shelter medicine, was from the United

States. The feedback obtained was integrated into the final version of the DCE form. The form

was then pre-tested by four reviewers on 10 selected articles. Disagreements were discussed and

changes were made to increase relevance and clarity of the DCE form prior to use. The final

DCE form can be found in Appendix A. All reviewers that helped with DCE had to complete the

10 pre-test articles to ensure consistency in DCE. Disagreements among reviewers were resolved

by consensus between the DCE pair, and if an agreement could not be made a third-reviewer was

brought in to resolve it. At this stage, the DCE form was used to confirm relevance and to extract

important information from the full articles of the relevant citations. The DCE form was used to

extract information including publication year and type; companion animal type; population

type; the main themes and outcomes investigated; study design and data collection methods;

control practices and their effectiveness; strengths and weaknesses; and the overall

recommendations put forward in the article. There were six reviewers involved with this stage

and each article was reviewed by two reviewers independently. Three of the six reviewers were

fluent in Spanish, two of these reviewers were specifically brought on to review the articles

published in Spanish.

Review Management, Data Charting and Analysis

Citations captured by the search were uploaded to RefWorks (Thomson ResearchSoft,

Philadelphia, PA). Citations were de-duplicated in Refworks and then imported into DistillerSR

software (DistillerSR, Evidence Partners, Ottawa, CA), an electronic review-management

program, for relevance screening and DCE.

54

Results from the DCE stage were downloaded as Excel spreadsheets (Microsoft Corporation,

Redmond, WA) and were formatted, cleaned and analyzed. As the “other” categories in main

themes or focus; reproduction control methods; euthanasia methods; outcomes of interest; and

recommendations were large, they were further searched for common terms or methods to create

new categories. Excel was used to create “heat maps” and bubble charts. The bubble charts

represent cross-tabulations between the major themes investigated in primary research articles by

the publication year and the study location. The size of the “bubbles” within each bubble chart is

proportional to the number of articles in each categorical pair (Petersen et al., 2008; Coe et al.,

2014).

To visualize the cross-tabulation of investigated control practices by publication year, study

location, study design, companion animal population and companion animal population type, a

“heat map” table was created. Cell values were shaded on a grey scale, which represents the

percentage of articles within in each cross-tabulation category out of the total number of articles

investigating a control practice (n=301).

Results

Descriptive Characteristics of Published Research on Population Dynamics and Control

Practices

A total of 7,810 unique citations were found through the searches (Figure 2.1). Relevance

screening indicated 1,353 citations were potentially relevant. These were procured as full

articles. Among these citations, 26 books, theses or conference proceedings were procured and

found to contain more than one relevant chapter or research article. Each of these potentially

relevant chapters or research articles was subsequently treated as a unique citation, resulting in

the edition of 410 citations (producing a total of 1753 potentially relevant citations). After

55

completing DCE, 869 of the citations were confirmed truly relevant, including 450 primary

research articles and 419 reviews (Figure 2.1). Tables 2.2 and 2.3 provide details on the main

characteristics extracted from the articles.

The majority of the articles were published from 2000 onwards (69.1%) with the median year

being 2005 and a range from 1950-2015. There were 216 articles (24.9%) published in the last

four years (Figure 2.2). Most of the articles were based on work from the United States (41.3%)

and journal articles were the most common type of document published (76.4%) (Table 2.2).

The majority of the articles did not specify a target stakeholder (52.0%); however when broken

down into primary research and reviews, reviews more frequently reported a stakeholder (62.8%)

(Table 2.2). The most common stakeholders identified in both primary research and reviews

were individuals of the veterinary community (27.5%), animal welfare

organizations/professionals (17.5%) and society (14.0%) (Table 2.2).

The relevant articles mainly focused on cats (67.4%) or dogs (59.3%) as the companion animals

of interest, with a slightly higher focus on cats (Table 2.3). Unowned free roaming companion

animals, which includes feral and stray, were the main type of population studied (69.3%).

Control practices were the main focus of the articles included (Table 2.3). The majority of the

articles that focused on control practices studied reproduction control methods or programs

(62.7%) (Table 2.3). Non-surgical (23.0%), trap neuter release (TNR) (18.4%) and low cost

(14.7%) reproduction control were the top reproduction control methods or programs

investigated. Non-surgical was further broken down into subcategories with chemical castration

(7.2%), zona pellucida immunocontraception (6.5%) and GnRH immunocontraception (6.3%)

being the three most common non-surgical methods discussed in both primary research and

reviews (Table 2.3). Euthanasia was the next most common major control practice reported.

56

The main outcome of interest reported was improving methodology (64.6%). Views and

opinions on free roaming and unwanted companion animals as well as views on factors affecting

free roaming and unwanted companion animals (35.2%) were also a main focus and outcome of

many articles (Table 2.3).

The effectiveness of control practices was reported in a majority of the articles that investigated

or discussed control practices (492, 56.6%). Effectiveness was more commonly reported in

reviews (288, 58.5%) than primary research (204, 41.5%). A total of 24 primary research articles

and 69 reviews reported the effectiveness of TNR, 16 primary research articles and 34 reviews

reported the effectiveness of chemical castration and 18 primary research articles and 27 reviews

reported the effectiveness of ZP immunocontraception.

Many different recommendations were reported in the literature (Table 2.4). Further research or

development of control practices (37.1%), recommending reproduction control (34.3%),

controlling the free roaming and unwanted population size (32.0%) and increasing public

education (31.9%) were the main recommendations.

There were also 299 articles classified as other, which indicated many articles mentioned issues

of or recommendations for free roaming and unwanted companion animals but the main focus of

the articles was not companion animal population dynamics or control practices (e.g., prevalence

of disease, population dynamics of native species).

Characteristics of Primary Research

The majority of primary research articles were cross-sectional observational studies (30.0%).

Data were most commonly collected by the research authors (329, 73.1%) compared to

veterinarians, shelter workers, public health professionals, members of society, trained

57

interviewers, and other individuals and used quantitative questionnaires (38.9%) or observations

(41.3%) (Table 2.5). Most of the primary articles reported prevalence (79.1%) outcomes. For

example, data from surveys (e.g. number or percentage of individuals who allow their dog to

roam). Many authors also provided p values and measures of variability (Table 2.5). Graphs

were commonly provided in studies as another way to report the data (229, 50.9%). Most authors

reported at least one strength (59.6%) and/or one weakness (55.3%) of the study. Further details

on the methodology, outcomes and reporting characteristics are reported in Table 2.5.

The main themes of primary research articles are stratified against location and publication date

in Figure 2.3 and 2.4. Over the years, primary research articles investigating population

dynamics, control practices and opinions on free roaming companion animals have increased.

The number of articles investigating surveillance specifically, doubled after 2009.

Table 2.6 stratifies different companion-animal control practices against publication year,

location, study design, animal population and population type. The results indicated that of the

301 primary research articles investigating control practices, reproduction control and euthanasia

were consistently focused on, with the amount of primary research articles investigating

euthanasia increasing over the years. Experimental studies were the most common study design

to investigate reproduction control while observational studies were the most common study

design to investigate euthanasia (Table 2.6). Unowned free roaming companion animals were

consistently the main target population for research on all of the different control practices

identified. An equal number of studies investigated reproduction control as a practice for

controlling population dynamics of free roaming and unwanted dogs and cats. Euthanasia,

confinement, mandatory spay and neuter and other types of control programs were more

commonly researched for controlling cat population dynamics while rehoming, vaccination,

58

legislations and education were more commonly researched for controlling the population

dynamics of dogs (Table 2.6).

Discussion

The results of this scoping review demonstrate the vast interest in and wide range of global

research into further understanding companion animal population dynamics. Further, the review

highlights the broad range of stakeholders invested in conducting research in this area.

Examining companion animal population dynamics on a global scale provides a broad

understanding of stakeholders’ perspectives and priorities from countries where the topic has

been studied. For example, the context of captured research ranged from eradication of invasive

species (i.e., feral cats) in Australia (Algar, Burbidge and Angus, 2002; Algar, Angus and Onus,

2011; Kennedy et al., 2012), to controlling free roaming dog reproduction and rabies in India

(Reece and Chawla, 2006; Totton et al., 2010; Yoak et al., 2014).

The increasing number of articles being published each year on this topic further demonstrates

the immense interest in companion animal population dynamics, and that the subject continually

gains more attention. In addition, it suggests that companion animal population dynamics are still

affecting many areas around the world. For example, in 2012 to 2013, in Bangladesh a catch

neuter vaccinate release program was conducted to control rabies and the dog population (Tenzin

et al., 2015), in Kashmir over 13852 dog bites were reported between April 2010 and May 2013

with 96% of them due to stray dogs (Lone et al., 2014) and in Hawaii a survey conducted in

2011 on stakeholders’ opinions on feral cats indicated that 86.9% respondents wanted to see the

number of cats decrease (Lohr and Lepczyk, 2014). Furthermore, as there are almost as many

reviews as there are primary research articles, it supports that this topic is highly discussed and

debated by many different stakeholders.

59

Despite companion animal population dynamics being a worldwide issue, a majority of the

relevant articles were from the United States. Only a few articles were conducted in Canada,

South America and Africa and there were pockets of research conducted in Asia (India) and

Europe (United Kingdom and Italy). The large number of articles published in the United States

could be a result of the way Americans view companion animals, as 95% of pet owners see their

pet as a friend and 87% of pet owners considered their pet a family member (Walsh, 2009). This

view suggests that Americans have a difficult time viewing free roaming companion animals as

wildlife and also have sympathy for unwanted companion animals which could impact the

control practices being researched and also increase the desire or need for research to be

conducted on these populations. In addition, the large amount of articles published in the United

States could be a result of overcrowded shelters and the desire to improve the situation. Previous

research has indicated that approximated 60% of the animals that entered U.S. shelters were

euthanized (Rowan, 1992; Wenstrup and Dowidchul, 1999). It was reported that the shelters only

had enough capacity to house 2.6% of the animals entering and that 34% of the animals

euthanized was due to capacity (Wenstrup and Dowidchul, 1999). As companion animal

population dynamics is diverse and can affect areas around the world differently, more research

needs to be conducted in these regions to understand the different issues each area faces, and to

understand different issues within each country or culture associated with controlling free

roaming and unwanted companion animals.

The total number of articles (primary research and reviews) focusing on control practices was

greater than the number of articles focusing on companion animal population dynamics,

surveillance, and views on free roaming and unwanted companion animal populations or

methods used to control them. Understanding the biological factors that influence the free

60

roaming and unwanted companion animal populations, such as migration, births and deaths

(ultimately determining the size of the population), could play a vital role in the success of

control programs being implemented. Also, society has to accept and support the type of control

program being used for the program to be successful (Mahlow and Slater, 1996; Lohr and

Lepczyk, 2014). There is an opportunity for more research to be conducted on the biological

factors that influence the population size of free roaming and unwanted companion animals, as

well as societal perceptions on control practices, to aid in the development of successful and

accepted policies surrounding the control of these populations.

The difficult nature of obtaining free roaming population sizes may also explain why

surveillance was not the main focus of the majority of articles. However, between the years 2010

and 2015, the number of articles that focused on surveillance almost doubled compared to

previous year groupings of before 2000, and 2000 to 2009, suggesting a recent increase in

research focus on this area. In addition, it could be related to the recent increase in use of the

mark-resight or sight-resight method, which was described as a simple way of obtaining the

population size of free roaming animals (Hiby et al., 2011; Punjabi, Athreya and Linnell, 2012).

Research should continue to focus on surveillance of free roaming companion animals, as

accurate data on population size are important to fully understand the effect of interventions on

companion animal population dynamics, in order to inform evidence-based control programs.

In the primary research articles, euthanasia as a control practice was more commonly researched

in the United States and Canada; and Oceanic countries compared to European, Asian or other

countries. This could be related to attitudes towards euthanasia in Europe and Asia as certain

laws and religions do not allow its promotion or practice (Hsu, Severinghaus and Serpell, 2003;

Voslářá and Passantino, 2012). The larger number of articles investigating euthanasia in Oceanic

61

countries is likely due to the many eradication programs conducted in Australia and surrounding

islands (Algar, Burbidge and Angus, 2002; Algar, Angus and Onus, 2011; Kennedy et al., 2012;

Koch, Algar and Schwenk, 2014). It has been suggested that one of the reasons the domestic cat

was brought to Australia and surrounding islands was to control rat and mice populations (Algar,

Angus and Onus, 2011). As a result, free roaming cats are considered an invasive species (Algar,

Burbidge and Angus, 2002; Koch, Algar and Schwenk, 2014); therefore, many Australians may

not have a negative view of the eradication of these cats and may be more accepting of

euthanasia as a control option.

In the current scoping review, unowned free roaming companion animals were identified as the

main population of focus, within the large body of research investigating companion animal

population dynamics. It is likely that unowned free roaming companion animal populations are

studied most often because control practices can be implemented without the consent of the pets’

owner, and in some countries members of society may consider these populations to be a

nuisance (Fielding and Mather, 2001; Poss and Bader, 2007; Gunther et al., 2015) and support

research and the control of these animal populations. In comparison, few articles investigated or

discussed owned free roaming and unwanted companion animals. Interestingly, within several

publications the authors still recommended improve animal identification use, and the promotion

of responsible pet ownership, which suggests that owned free roaming and unwanted companion

animals are still a population of interest with respect to companion animal population dynamics

and control. More research on the ecological, animal health, and public health impacts of these

populations and the methods needed to control them is required, to provide a fuller

understanding of this area.

62

Zoonotic diseases and other public health issues (animal bites and sanitation) were discussed

across much of the published research, more specifically within review articles. This indicates

that many individuals are discussing zoonotic disease and other public health issues in regards to

population dynamics but few primary research articles investigate these topics in the context of

population dynamics. The large amount of reviews discussing these topics suggest that

stakeholders believe that free roaming companion animals pose a risk to humans and other

species through disease spread, attacks and predation (Duffy and Capece, 2012; Nogales et al.,

2013; Hughes and MacDonald, 2013; Kachani and Health, 2014). The number of reviews and

commentaries that focused on the relationship between companion animal population dynamics

and public health issues suggests that more primary research is needed in this area including

research into the role of population dynamics in the spread of zoonotic diseases. Understanding

this information would not only improve the health and lives of humans living with free roaming

and unwanted companion animals, but also improve the health of free roaming companion

animals.

Almost all of the primary research articles reported at least some of their data in an extractable

way (94.5%), providing an opportunity for further synthesis and the potential for systematic

reviews. Prevalence outcomes were the most common measure reported in the results of primary

research collected during this scoping review, which aligns with the large amount of

observational studies that we identified. Many studies were looking at interventions, to

understand the effect on population size and not the risks or causality of the exposure and

outcome. Due to the nature of free roaming populations, proper experimental studies are

extremely challenging to determine the efficacy of control practices. However, studies

developing or investigating new non-surgical reproduction control products were generally

63

conducted using controlled trials, which suggests that primary research on non-surgical

reproduction control may offer a specific area for further knowledge synthesis efforts.

It has been suggested that free roaming and unwanted companion animals can negatively impact

humans (Sriaroon et al., 2006; Farnworth et al., 2012; Lone et al., 2014; Jain and Jain, 2014;

Gunther et al., 2015), other animals (Baker et al., 2008; Hervías et al., 2014), and the

environment, likely resulting in the large volume of published research focused on investigating

at least one type of control practice to manage companion animal populations. A large number of

studies have investigated and discussed different methods of reproduction control, and

euthanasia offering other potential areas for subsequent SR-MA that focus on the effectiveness

of these control practices. Specifically, prioritizing SR-MAs on the effectiveness of trap neuter

programs, non-surgical control methods, zona pellucida immunocontraception and chemical

castration, or the euthanasia method, poison, may be considered given the vast body of primary

research on these control practices reporting their effectiveness. More recent commentaries on

companion animal control measures have suggested the need for alternatives to surgical

sterilization, with a call for non-surgical reproduction control methods (Roberston, 2008;

Kuztler, 2010), which further highlights the value of prioritizing this area above all. Determining

the true effectiveness of control practices, through completing a SR-MA where possible, could

further help to inform policy decisions, allocation of resources and ultimately lead to the creation

of successful control programs. Although a wide variety of other companion animal population

control practices, such as mandatory spay and neuters, confinement, legislations and education,

have been investigated over the years, few studies investigated their effectiveness at controlling

free roaming and unwanted companion animals or mitigating the impacts caused by these

populations. As a result, further primary research into the effectiveness of other control practices

64

is likely necessary to inform the inclusion or exclusion of these practices within evidence-based

companion animal population control programs.

Few studies identified in the current review used mathematical modeling, yet it may provide a

good alternative to help inform the efficacy of control practices before investing resources.

Further research into the use of mathematical modeling and the ability to use modelling to

provide predictions on the relative performance of different control practices could result in more

successful control programs and aid in determining how to allocate resources. This said, in order

for a mathematical model to successfully assess the impact of a control practice, several

parameters need to be known including the free roaming population size, and obtaining such

information can be difficult (Flockhart, Norris and Coe, 2016). This may explain why more

mathematical models have not been developed to inform interventions to address issues relating

to companion animal population dynamics.

Despite the large amount of research that has already been conducted on this topic, a large

number of published articles are still calling for further research on the topic and further

development of control practices, indicating that free roaming and unwanted companion animals

are still an area of high interest for stakeholders. This may suggest that research on companion

animal population dynamics is complex and involves many areas and aspects of additional or

follow up research. Conducting follow-up SR-MA in this area could provide more information

on the efficacy of control practices, support mathematical models and determine if or where

further primary research is necessary.

Many reviews discuss public education and many authors of primary research and reviews

recommend increased public education on this issue, yet few primary research articles have

investigated the efficacy of education programs. Education programs that have been

65

implemented and researched include educational courses on how to prevent dog bites and

infections from dogs (Kato et al., 2003), an education curriculum for elementary schools on

overpopulation and companion animal reproduction control methods (Avanzio, 1991) to improve

the knowledge of the participants, educational booklets on rabies and rabies prevention to

improve the knowledge, attitudes and practice of participants (Matibag et al., 2009), and on pet-

care including benefits of sterilization to determine if it would improve dog retention, increase

the decision to spay or neuter and improve knowledge of pet-care (Weng et al., 2006). It is also

interesting to note that the number of primary research articles that investigated education have

been decreasing over the years. Developing an educational program that is beneficial to all pet

owners can be difficult as pet owners have different knowledge levels on pet care (Weng et al.,

2006); this may explain why few primary research articles have investigated educational

programs. Further research on education programs is needed, as they are being recommended

without a large body of supporting evidence conducted in different populations ad contexts. It is

important to understand the effects education have on the target population and in turn their

companion animal population.

The number of articles considered as ‘other’ further indicates that the research interest into the

control and population dynamics of free roaming and unwanted companion animals intersects

with many different research fields. Despite the fact that the main focus of these articles did not

align with the current scoping review’s interest, the number classified as “other” supports that

many stakeholders are interested in the impacts that can be caused by free roaming and unwanted

companion animals including the impacts on the population dynamics of native species, and

disease spread to both humans and other animals as a result of infected free roaming and

66

unwanted companion animals (Kilonzo and Komba, 1993; Forys and Humphrey, 1999; Ward et

al., 2011; Wang et al., 2012)..

Limitations

The current review did not include an exclusive grey literature search due to time and resource

constraints. The exclusion of grey literature obtained from relevant websites could have resulted

in some relevant unpublished articles being missed. However, a comprehensive hand search was

used to verify the search strategy and to minimize the number of any potential missed articles.

There is also no standardized approach to conducting a grey literature search (Eysenbach,

Tuishce and Diepgen, 2001) and it can be difficult to create precise search strategies to locate

relevant articles (Conn et al., 2003). As a result, we believe that the current scoping review still

captures the current state of knowledge on approaches to managing companion animal

population dynamics to control the number of owned free-roaming, unowned free-roaming and

unwanted companion animals.

Another limitation of the current scoping review is that we only included articles published in

English and Spanish. As almost half of the articles excluded due to language were written in

Portuguese, this could account for the lower number of articles published in South America

(Brazil) and or Europe (Portugal). The impact of excluding these articles is not known, future

researchers should try to include as many languages as is feasible. As well, some articles could

not be obtained and therefore, their relevance could not be confirmed. However, given the small

number of articles in this category, it is unlikely that their exclusion would significantly affect

the results.

Conclusion

67

A large number of published research articles on the topic of companion animal population

dynamics were captured and summarized in this review, indicating the global importance of this

research area. Reproduction control programs were the most commonly investigated control

program among the included articles, specifically TNR and non-surgical control methods such as

chemical castration and zona pellucida immunocontraception. These areas of research provide

potential opportunities for further knowledge synthesis activities in the form of SR-MAs to

determine a more accurate measure of the efficacy of such control programs. Primary research

consistently reported prevalence values which also provides opportunities for future SR-MAs.

Research gaps were identified on other control practices (such as public education), population

dynamics, surveillance, and views on free roaming and unwanted companion animals which

warrant further investigation. As more relevant research is conducted on free roaming and

unwanted companion animals, this review should continue to be updated to prioritize further

research and identify ongoing research gaps.

68

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Totton, S. C., Wandeler, A. I., Zinsstag, J., Bauch, C. T., Ribble, C. S., Rosatte, R. C., &

McEwen, S. A. (2010). Stray dog population demographics in Jodhpur, India following a

population control/rabies vaccination program. Preventive Veterinary Medicine, 97, 51-57.

72

Tricco, A. C., Tetzlaff, J., & Moher, D. (2011). The art and science of knowledge synthesis.

Journal of Clinical Epidemiology, 64, 11-20.

Walsh, F. (2009). Human-animal bonds I: the relational significance of companion animals.

Family Process, 48, 462-480.

Weng, H. Y., Kass, P. H., Chomel, B. B., & Hart, L. A. (2006). Educational intervention on dog

sterilization and retention in Taiwan. Preventive Veterinary Medicine, 76, 196-210.

Wenstrup, J., & Dowidchuk, A. (1999). Pet overpopulation: data and measurement issues in

shelters. Journal of Applied Animal Welfare Science, 2, 303-319.

Yoak, A. J., Reece, J. F., Gehrt, S., & Hamilton, I. M. (2014). Disease control through fertility

control: secondary benefits of animal birth control in Indian street dogs. Preventive Veterinary

Medicine, 113, 152-156.

Zain, S. N. M., Sahimin, N., Pal, P., & Lewis, J. W. (2013). Macroparasite communities in stray

cat populations from urban cities in Peninsular Malaysia. Veterinary Parasitology, 196, 469-477.

73

TABLE 2.1

Key Definitions used in the Relevance Screening and Data Extraction Form

Term Definition

Companion animals Any animal species kept for companionship

and enjoyment or a household animal, as

opposed to livestock, laboratory animals,

working animals or sport animals, which are

kept for economic reasons.

Owned free-roaming companion animals Owned companion animals that are straying

from the owner’s residence or property.1

Unowned free-roaming companion animals Unowned companion animals that are stray or

feral. 2, 3, 4

Unwanted companion animals Companion animals who are not free-roaming

but are being surrendered to a shelter,

abandoned, are being given away, are being

sold, killed, or euthanized by their owners.5

Owned uncertain companion animals Companion animals as owned companion

animals but roaming status was not stated.

Population dynamics Any process that affects the size and/or

structure of a companion animal population

over time (e.g., births, deaths, migration).

Surveillance Monitoring the population size. 1Slater, et al., 2008

2Slater, 2004

3Faulkner, 1975

4Feldman & Carding, 1973

5Fielding, 2010

References

Faulkner, L.C. (1975) Dimensions of the pet population problem. Journal of the American

Veterinary Medical Association, 166, 5, 477-478.

Feldmann, B. M., & Carding, T. H. (1973). Free roaming urban pets. Health Services Reports,

88(10), 956-962.

74

Fielding, W.J. (2010). Dog breeding in New Providence, the Bahamas, and its potential impact

on the roaming dog population II: The fate of puppies. Journal of Applied Animal Welfare

Science, 13, 4, 300-313.

Slater, M.R., Di Nardo, A., Pediconi, O., Dalla Villa, P., Candeloro, L., Alessandrini, B., & Del

Papa, S. (2008). Free-roaming dogs and cats in central Italy: Public perceptions of the problem.

Preventive Veterinary Medicine, 84, 27-47.

Slater, M.R. (2004). Understanding issues and solutions for unowned, free-roaming cat

populations. Journal of the American Veterinary Medical Association, 225, 9, 1350-1354

75

TABLE 2.2

Descriptive Characteristics of 869 Primary-Research and Review and Commentary Articles

Investigating or Discussing the Issue of Companion-Animal Population Dynamics

All articles

(n =869)

Primary

research

(n =450)

Reviews and

commentaries

(n =419)

Question No. % No. % No. %

Document type

Journal article 664 76.4 394 87.6 270 64.4

Book or book chapter 80 9.2 12 2.7 68 16.2

Conference proceedings paper or

abstract 56 6.4 11 2.4 45 10.7

Thesis or dissertation 29 3.3 26 5.8 3 0.7

Report 14 1.6 4 0.9 10 2.4

Lay magazine article 11 1.3 1 0.2 10 2.4

Other 15 1.6 2 0.4 13 3.1

Study location

United States 359 41.3 158 35.1 201 48.0

Australia 65 7.5 51 11.3 14 3.3

India 31 3.6 23 5.1 8 1.9

United Kingdom 23 2.6 11 2.4 12 2.9

Italy 15 1.7 15 3.3 0 0

Canada 6 0.7 4 0.9 2 0.5

Multiple countries 119 13.7 6 1.3 113 27.0

Other 171 19.7 150 33.3 21 5.0

Not reported /applicable 80 9.2 32 7.1 48 11.5

Article Language

English 843 97.0 432 96.0 411 98.1

Spanish 25 2.9 17 3.8 8 1.9

Source of Fundinga

Government 137 15.8 113 25.1 24 5.7

76

University 76 8.7 71 15.8 5 1.2

Industry 67 7.7 53 11.8 14 3.3

Public health agency 21 2.4 15 3.3 6 1.4

Other 165 19.0 130 28.9 35 8.4

Not reported 548 63.1 190 42.2 358 85.4

Author reported stakeholdersa

Not clear or not explicitly reported 452 52.0 296 65.8 156 37.2

Veterinarians or veterinary

community 239 27.5 52 11.6 187 44.6

Animal welfare (shelters, rescues,

organizations) 152 17.5 56 12.4 96 22.9

Society 122 14.0 44 9.8 78 18.6

Animal control or pound 60 6.9 26 5.8 34 8.1

Public health 54 6.2 13 2.9 41 9.8

Ecologists, conservationists and

wildlife managers 49 5.6 20 4.4 29 6.9

Government 44 5.1 15 3.3 29 6.9

Cat colony managers 19 2.2 6 1.3 13 3.1

Breeders 16 1.8 3 0.6 13 3.1

Corporation, institution or business 14 1.6 6 1.3 8 1.9

Spay neuter groups 11 1.3 6 1.3 5 1.2

Other 113 13.0 52 11.6 61 14.6

a Column percentages do not add up to a 100% as multiple selections were allowed for these

questions

77

TABLE 2.3

Main Areas of Focus in the 869 Primary-Research and Review and Commentary Articles

Investigating or Discussing the Issue of Companion-Animal Population Dynamics

All articles

(n= 869)

Primary

research

(n =450)

Reviews and

commentaries

(n =419)

Question No. % No. % No. %

Companion-animal populations studieda

Cats 586 67.4 259 57.6 327 78.0

Dogs 515 59.3 254 56.4 261 62.3

Other 84 9.7 44 9.8 40 9.5

Type of companion animal populations

studieda

Un-owned free roaming 602 69.3 301 66.9 301 71.8

Unwanted 310 35.7 116 25.8 194 46.3

Owned uncertain 279 32.1 127 28.2 152 36.3

Owned free roaming 248 23.5 131 29.1 117 27.9

Not reported 70 8.1 31 6.9 39 9.3

Primary themes of the investigation or

discussiona

Control practices 697 80.2 298 66.2 399 95.2

Population dynamics 354 40.7 233 51.8 121 28.9

Surveillance 262 30.1 206 45.8 56 13.4

Views and opinions 245 28.2 90 20.0 155 37.0

Animal welfare 52 6.0 9 2.0 43 10.3

Other 130 15.0 67 14.9 63 15.0

Type of control practice investigateda

Reproduction controla 545 62.7 204 45.3 341 81.4

Non-surgicala 200 23.0 72 16.0 128 30.5

Chemical castration 62 7.1 18 4.0 44 10.5

78

Zona pellucida glycoproteins

immunocontraceptive 55 6.3 18 4.0 37 8.8

GnRH immunocontraceptive 54 6.2 10 2.2 44 10.5

Progestins 47 5.4 4 0.9 43 10.3

Hormonal implants 38 4.4 5 1.1 33 7.9

Other 94 10.9 19 4.2 75 17.9

Not specified 15 1.7 2 0.4 13 3.1

Trap Neuter Release 160 18.4 51 11.3 109 26.0

Low cost or subsidized 128 14.7 30 6.7 98 23.4

Traditional 114 13.1 29 6.4 85 20.3

Other neuter programs 76 8.7 29 6.4 47 11.2

Early 73 8.4 15 3.3 58 13.8

Other 70 8.1 9 2.0 61 14.6

Not specified 32 3.7 16 3.6 16 3.8

Euthanasiaa 332 38.2 113 25.1 219 52.3

Poison 80 9.2 24 5.3 56 13.4

Shooting 67 7.7 22 4.9 45 10.7

Intravenous injection 31 3.6 8 1.8 23 5.5

Trap and euthanize 30 3.5 7 1.6 23 5.5

Gas 23 2.6 3 0.7 20 4.8

Biological control 22 2.5 7 1.6 15 3.6

Blunt force trauma 10 1.2 0 0.0 10 2.4

Electrocution 10 1.2 0 0.0 10 2.4

Drowning 10 1.2 0 0.0 10 2.4

Other 69 7.9 22 4.9 47 11.2

Not specified 177 20.4 58 12.9 119 28.4

Education 142 16.3 24 5.3 118 28.2

Rehoming 133 15.3 45 10.0 88 21.0

Legislation/Regulationsa 126 14.5 31 6.9 95 22.7

Licensing and registration 95 10.9 26 5.8 69 16.5

79

Breeding laws 26 3.0 2 0.4 24 5.7

Responsible Ownership Laws 11 1.3 2 0.4 9 2.1

Other 71 81.7 11 2.4 61 14.6

Not specified 7 0.8 2 0.4 5 1.2

Confinement 74 8.5 13 2.9 61 14.6

Mandatory spay and neuter 50 5.8 12 2.7 37 8.8

Do nothing 10 1.2 5 1.1 5 1.2

Other 134 15.4 52 11.6 82 19.6

Outcome investigateda

Improve methodology of control

practices 561 64.6 217 48.2 344 82.1

Views/opinions on free roaming/

unwanted companion animals 306 35.2 104 23.1 202 48.2

Free roaming/ unwanted companion

animal size 266 30.6 153 34.0 113 27.0

Zoonotic disease 221 25.4 68 15.1 153 36.5

Animal characteristics 218 25.1 165 36.7 53 12.6

Number of euthanized free roaming

unwanted companion animals 201 23.1 91 20.2 110 26.3

Animal reproduction ability 199 22.9 141 31.3 58 13.8

Other public health/safety issues (e.g.,

animal bites, sanitation) 168 19.3 56 12.4 112 26.7

Protect the environment and other

species 159 18.3 63 14.0 96 22.9

By-laws and legislations 130 15.0 30 6.7 100 23.9

Number of shelter intakes 111 12.8 61 13.6 50 11.9

Cost benefit of a control program for

free roaming/ unwanted companion

animals 91 10.5 34 7.6 57 13.6

Non-zoonotic disease 84 9.7 27 6.0 57 13.6

Number of adoptions 81 9.3 54 12.0 27 6.4

Ownership statistics 77 8.9 48 10.7 29 6.9

80

Spatial movement or data 55 6.3 44 9.8 11 2.6

Human demographics 53 6.1 46 10.2 7 1.7

Prevalence of disease in free roaming/

unwanted companion animals 47 5.4 24 5.3 23 5.5

Number of free roaming/unwanted

companion animals in shelters 41 4.7 22 4.9 19 4.5

Ectoparasites 36 4.1 11 2.4 25 6.0

Other 378 43.5 225 50.0 153 36.5

a Column percentages do not add up to a 100% as multiple selections were allowed for these

questions

81

TABLE 2.4a

Author-Reported Recommendations from the 869 Primary-Research and Review and

Commentary Articles Investigating or Discussing the Issue of Companion Animal Population

Dynamics

All

articles (n =869)

Primary

research (n =450)

Reviews and

commentaries

(n =419)

Question

No. % No. %

No. %

Further research 322 37.1 207 46.0 115 27.4

Reproduction Controla 298 34.3 116 25.8 182 43.4

Low Cost Spay and Neuter 67 7.7 21 4.7 46 11.0

Non-surgical Reproduction

Controla 49 5.6 13 2.9 36 8.6

Chemical castration 9 1.0 5 1.1 4 1.0

GnRH

immunocontraceptive 3 3.5 2 0.4 1 0.2

Zona Pellucida

glycoproteins

immunocontraceptive 4 0.5 2 0.4 2 0.5

Hormonal implants 1 0.1 1 0.2 0 0.0

Other 14 1.6 7 1.6 6 1.4

Not specified 14 1.6 0 0.0 14 3.3

Early 51 5.9 19 4.2 32 7.6

Traditional 35 4.0 9 2.0 26 6.2

Trap Neuter Release 48 5.5 20 4.4 28 6.7

Other Neuter Programs 28 3.2 16 3.6 12 2.9

Other 49 5.6 11 2.4 38 9.1

Not specified 45 5.2 20 4.4 25 6.0

82

Control free roaming/unwanted

population size 278 32.0 135 30.0 143 34.1

Increase public education 277 31.9 117 26.0 160 38.2

Enforce new and or existing

legislations/ regulationsa 134 15.4 40 8.9 94 22.4

Licensing and registration 89 10.2 23 5.1 66 15.8

Breeding laws 27 3.1 7 1.6 20 4.8

Other 78 9.0 15 3.3 63 15.0

Not specified 7 0.8 2 0.4 5 1.2

Improve data or monitoring 121 13.9 68 15.1 53 12.6

Collaboration of stakeholders 112 12.9 34 7.6 78 18.6

Control the spread of disease 101 11.6 43 9.6 58 13.8

Promote responsible pet

ownership 97 11.2 31 6.9 66 15.8

Increase vaccination 94 10.8 40 8.9 54 12.9

Confinement 78 9.0 27 6.0 51 12.2

Guidelines 70 8.1 25 5.6 45 10.7

Consider or change public

views/opinions/attitudes/religions

or gain public’s support 60 6.9 30 6.7 30 7.2

Increase the number of free

roaming/ unwanted companion

animals 55 6.3 22 4.9 33 7.9

Protect the environment and

species 53 6.1 28 6.2 25 6.0

Mandatory spay and neuter 50 5.8 8 1.2 42 10.0

Increase education or training of

stakeholders 48 5.5 19 4.2 29 6.9

Increase euthanasiaa 49 5.6 14 3.1 35 8.4

Poison 9 1.0 5 1.1 4 9.5

Shooting 5 0.6 3 0.7 2 4.8

Intravenous injection 1 0.1 0 0.0 1 2.4

Gas 1 0.1 0 0.0 1 2.4

83

Other 25 2.8 7 1.6 18 4.3

Not specified 15 1.7 3 0.7 12 2.9

Improve or promote ID use 46 5.3 16 3.6 30 7.2

Decrease euthanasiaa 45 5.2 10 2.2 35 8.4

Poison 2 0.2 1 0.2 1 0.2

Other 9 1.0 2 0.4 7 1.7

Not specified 35 4.0 8 1.8 27 6.4

Obtain or relocate funding 33 3.8 12 2.7 21 5.0

Restrict companion animal access

to resources 29 3.3 12 2.7 17 4.1

Use a multifaceted approach 21 2.4 3 0.7 18 4.3

Understand population dynamics 19 2.2 8 1.8 11 2.6

Not specified 124 14.3 66 14.7 58 13.8

Other: 283 32.6 136 30.2 145 34.6

a All column percentages do not add up to a 100% as multiple selections were allowed for these

questions

84

TABLE 2.5

Methodological, Outcomes and Reporting Characteristics of 450 Primary-Research Articles

Investigating the Issue of Companion-Animal Population Dynamics

Characteristic No. %

Study type (n = 450):

Cross-sectional 134 30.0

Cohort 19 4.2

Case-control 4 0.9

Other observational study: 23 5.1

Controlled trial 58 12.9

Quasi-experiment 21 4.7

Other experimental study: 14 3.1

Qualitative 7 1.6

Routine monitoring or surveillance data collection 67 14.9

Mathematical model or methodology study 34 7.6

Other: 68 15.1

Data collection methodsa (n =450)

Observations/field visits 186 41.3

Quantitative questionnaires or surveys 175 38.9

Analysis of records or database 122 27.1

Qualitative interviews 13 2.9

Focus groups 5 1.1

Other 201 44.7

Not specified 9 2.0

Reported data in an extractable waya 430 95.6

Prevalence outcome 356 79.1

Continuous outcome 302 67.1

P values 264 58.7

85

Measure of variability (e.g., standard deviation,

standard error, confidence intervals) 232 51.6

Dichotomous outcome 79 17.6

Spatial analysis 62 13.8

Ordinal/ Likert scale 52 11.6

Modelling coefficients/ beta parameters 46 10.2

Measure of association (e.g., odds ratio, relative risk) 45 10.0

Other: 200 44.4

Reported data in an non-extractable way (e.g., graph) 244 54.2

Reporting of study strengths and limitations (n =450 )

At least one strength reported 268 59.6

At least one limitation reported 249 55.3

a Column percentages do not add up to a 100% as multiple selections were allowed for these

questions

86

TABLE 2.6

Scoping Review Evidence Map Identifying the Number of Studies Investigating Control

Practices among 301 Primary Research Articles

Characteristics

Spay and Neuterb Euthanasiab Legislationb Rehomingb Educationb Confinementb

Mandatory SNb Otherb Totalb

Publication Year

Before 2000 45 29 13 11 11 3 4 3 119

2000-2009 81 30 8 15 10 1 3 20 168

2010-2015 77 53 10 19 3 9 5 28 204 Study Location

United States 93 46 16 31 15 9 8 25 243

Europe 14 4 6 6 0 2 2 4 38

Asia 28 9 3 1 7 1 0 1 50

Oceania 9 33 2 2 0 1 1 13 61

Multiple 3 4 1 3 0 0 0 1 12

Other 27 13 3 2 2 0 1 6 54

Study Design

Experimental 72 18 1 1 2 0 0 8 102

Observational 57 40 11 21 4 5 3 18 159 Mathematical Model 26 13 4 4 3 4 0 7 61 Routine Monitoring 20 20 10 10 7 2 5 10 84

Qualitative 2 5 1 2 0 0 1 0 11

Other 27 17 4 7 8 2 3 9 77

Companion-animal population

Dogs 113 55 24 37 22 5 7 21 284

Cats 115 81 19 27 13 10 11 42 318

Other 19 13 0 2 1 0 0 3 38 Population Type

Unowned free roaming 121 95 24 30 16 13 10 45 354 Owned free roaming 42 32 17 9 9 10 7 20 146

Unwanted 54 42 14 35 13 2 6 13 179 Owned uncertain 58 21 16 17 13 4 6 10 145

Not reported 30 1 0 0 0 0 0 0 31

Total 1133 674 207 292 159 83 83 307

87

Data are stratified by publication year and location, study design, and companion animal

population and companion animal population types investigated.

aCell shades represent the percentage of articles in each cross-tabulation category out of the total

number of articles investigating reasons for relinquishment (n = 84).

Legend:

0-5% 6-10% 11-20% 21-30% >30%

bMultiple selections were allowed (i.e., studies can be counted in more than one column and/or

row).

88

Figure 2.1 Scoping review flow-chart

Records identified through

database searches

(n = 10784)

Duplicates removed

(n = 3240)

Reference list hand search

(n = 266)

Relevance screening

(n = 7810)

Citations excluded

(n = 6457)

Data Extraction and

Characterization

(n = 1763)

Full-text articles excluded:

Non-relevant (n = 409)

Language (n = 166)

Unable to obtain (n = 20)

Other (n = 299)

26 books, thesis,

conference proceedings

(n= 410 additional citations)

Studies included in

scoping review

(n = 869)

Citations

(n = 11050)

89

Figure 2.2 Frequency of the 869 relevant published articles by year

0

146

25

50

75

100

125

Fre

que

ncy

1950 1975 2000 2015year

90

Figure 2.3.

Scoping-review evidence map of the key aspects and themes among 450 primary-research

articles stratified by study location

7

11

70

51

61

13

28

109

56

74

35

50

118

99

98

Control Practices

Surveillance

2010-2015

Other

Opinions and views

Population Dynamics

Before 2000 2000-2009

91

Figure 2.4.

Scoping-review evidence map of the key aspects and themes among 450 primary-research

articles stratified by year of publication

22

39

115

67

85

10

10

23

28

27

7

11

34

27

31

15

10

43

36

34

3

2

6

2

2

8

18

46

44

48

Other

Opinions and views

Control Practices

Population Dynamics

Surveillance

U.S. Multiple Continents

OceaniaAsiaEurope Other

92

CHAPTER THREE

Factors influencing time to adoption for dogs in a provincial shelter system in Canada

93

Abstract

Millions of animals are relinquished to shelters each year. For each animal submitted, animal

characteristics, animal history and characteristics of the shelter holding the animal influence the

dog’s time to adoption. Identifying which characteristics have the greatest effect on time to

adoption is important because only some of these factors are under the direct control of shelters,

while others may be addressed via outreach, legislation, or education. This is the first study

exploring this topic in Canada. Using a Cox proportional hazards frailty model, these issues were

explored using data from 31 shelters within of the British Columbia Society for the Prevention of

Cruelty to Animals’ shelter system. Results indicated that surrender reason, age, original source,

coat colour, breed, human population density of the shelter location, and year the animal entered

the shelter system significantly influenced time to adoption. Our study identified characteristics

of dogs that make them less likely to be adopted quickly. Given limited resources, these results

could inform shelters how best to allocate their resources particularly around targeting

interventions to improve adoption rates in their shelters.

94

Introduction

Overcrowding is an issue faced by animal shelters around the world, leading to poor animal

welfare (Turner, Berry and MacDonald, 2012), increased animal stress (Hurley, 2005; Turner,

Berry and MacDonald, 2012) and increased risk of the spreading of infectious disease agents

among animals (Hurley, 2005; Pesavento and Murphy, 2014). It also can result in hundreds of

healthy adoptable companion animals being euthanized each year (Patronek and Zawistowski,

2002; Kass, 2007). To euthanize mass numbers of animals can be extremely stressful and

emotional for shelter workers (White and Shawhan, 1996; and Gardner, 2008), causing feelings

of depression and sleep deprivation, and it can also affect their personal lives (White and

Shawhan, 1996 and Reeve et al., 2005). Shelter employees find it more difficult euthanizing

dogs compared to cats, as they generally tend to form stronger attachments to the dogs

(Rogelberg et al., 2007). The human impact of overcrowding can lead to increased shelter

employee turnover (Rogelberg et al., 2007). Due to these effects on humans and companion

animals, many shelters are trying to implement interventions that maximize the probability of

successful outcomes (adoption, reclamation) and minimize the number of unsuccessful outcomes

(euthanasia, return to shelter).

Exploring the general characteristics of companion animals entering shelters provides an

opportunity to better understand which animal and shelter characteristics maximize the

probability of successful outcomes (i.e., adoption) and decrease length of stay. Decreasing length

of stay has been suggested to decrease the stress caused from being in a shelter for the

companion animals (Karsten, 2014), which improves animal welfare. Studies conducted to date

on shelter dogs have shown that females, puppies (under a year of age), purebreds and small

dogs are preferred by adopters over males, adults, mixed breeds and medium to large dogs

95

(Lepper, Kass and Hart, 2002; Diesel, Smith and Pfeiffer, 2007; DeLeeuw, 2010). It has also

been found that relinquishment reasons can affect adoption probability; dogs relinquished due to

owner-related reasons have been found to be more likely to be adopted compared to dogs

relinquished for behavioural or health reasons (Lepper, Kass and Hart, 2002; DeLeeuw, 2010).

Much of the research in this area to date has been conducted in the United States and the United

Kingdom, with no previous research conducted in Canada. In addition, no previous research has

been conducted to investigate animal and shelter characteristics associated with the probability of

successful adoption or reduced LOS for dogs having entered a shelter system using a Cox

proportional. Such research is needed because the outcome and solutions for companion animals

entering shelters may be influenced by geographical and cultural factors.

The purpose of this study was to determine the characteristics that affect a dog’s time to adoption

within a large multi-shelter system in British Columbia, Canada. Specifically, the primary

objective of the current study was to examine whether the source from where a dog was

originally obtained affects an animal’s length of stay in an animal shelter.

Methods

This study received approval from the University of Guelph Research Ethics Board.

Description of Data Set

Through a data sharing agreement, de-identified data on companion animals entering 36 British

Columbia Society for the Prevention of Cruelty Animals’ (BC SPCA) shelters, between January

2004 and July 2014, were provided to the research team at the University of Guelph. The BC

SPCA is a province wide animal sheltering system which uses shelter management practices

ascribed to Capacity for Care (C4C). C4C is a collection of shelter management approaches

96

implemented to decrease unnecessary euthanasia within shelters, decrease the amount of time an

animal spends in a shelter, decrease disease transmission risk and decrease overall animal intake

(Karsten, 2014). In addition, once capacity has been reached, under the C4C management

approach, animals are no longer allowed to be surrendered to the shelter (Newbury et al., 2010).

Due to incomplete data from 2004 to 2009 for a number of shelters in the BC SPCA system, only

data records from 2010 to 2014 were used in the current analysis. The original data were

extracted from the BC SPCA’s shelter database software, ShelterBuddy (ShelterBuddy Software,

RSPCA QLD Inc., 2012). To address the study objective, only records that contained

information relating to dogs and which identified an original source for the dog (i.e., where the

owner originally obtained the animal) were included. Furthermore, for dogs to be included in the

analysis, the dog must have had the opportunity to be adopted or euthanized, which included

shelter records where the dog was classified as: adopted (failure data), available for adoption, in

shelter, escaped, stolen, unassisted death or euthanized (censor data). Dogs in the shelter records

that did not have an opportunity for adoption or euthanasia were removed from analysis

including those classified as: returned (returned to the shelter after being adopted), redeemed,

returned to surrender (returned to the owners after they were relinquished), released, and dead on

arrival (arrived at the shelter deceased). Dogs classified as deceased (an adopted dog whose

status was updated in the system when it was reported the dog had died) were also removed as

adoption date was no longer listed. In addition, dogs that were euthanized or died on the day they

entered (i.e., had a length of stay of zero) were excluded from the analysis as they did not have a

true opportunity of being adopted. Similarly, dogs that were adopted on the day they entered the

shelter system were also excluded from the analysis. Dogs that were brought to foster-only

97

branches of the BC SPCA were excluded from the current analysis as these branches had zero

capacity to hold dogs.

Only data from the dogs’ first time of admission were included in the current analysis. Data for

dogs with repeated admissions where it was unclear which data matched their first admission

were also removed from analysis. For each dog contributing data to the study, their shelter record

included age, breed, coat color, source (how the dog was brought into the shelter) and original

source, sex (male versus female), surrender reason, incoming branch to the BC SPCA, incoming

date (year the animal entered the shelter and was available for adoption or euthanasia for the first

time), status history date (which represents the first status date of a dog that has been in a shelter

before), current status date, and outcome. The variables online source and length of stay in days

were created based on variables within the shelter records. There were four shelter-level

variables included in the analysis: branch, holding capacity for dogs, shelter type and population

centre (i.e., human population of local community where the BC SPCA branch was located).

Information on holding capacity and shelter type was provided directly by the BC SPCA. Data

on the human populations where the shelters are located were collected from Statistics Canada.

Dog age was divided into two categories (pup or dog) based on the age at which point the dog

arrived in the shelter. The classification used the BC SPCA’s cut-off of less than one year of age

for classifying a dog as a pup.

The database originally contained over 100 different categories for breed. A dog was categorized

as a purebred when only one breed was listed. Breed mixes were identified based on the primary

breed listed (e.g., Border Collie mix). In addition, Labrador mix contained breeds listed as

Labradoodles, Labradoodle mixes, Labrador retriever mixes or Labrador mixes. Husky mix

contained Siberian husky mixes and Husky mixes. Once a breed mix was referenced more than

98

400 times in the dataset, a breed mix category was added based on the primary breed identified

in the record. When a mixed breed had less than 400 data points it was included under the ‘other

mix’ category. Using this approach, breed was reduced to eight different breed categories (i.e.,

Purebred, Border Collie mix, German Shepherd mix, Husky mix, Labrador mix, Shih Tzu mix

and other mix) to facilitate analysis.

Coat colour originally contained hundreds of colours and colour combinations that were reduced

to seven categories: patterned, mixed, black, brown, white, yellow or grey. A dog was classified

as “patterned” when its coat colour was listed as a pattern (e.g., tri-colour, merle, brindle), either

in the recording of their primary or secondary coat colour. A dog was classified as mixed when

two different colours or patterns were recorded as the primary and secondary coat colour. In

situations where two colours comprise a pattern (e.g., black and tan or tan points) the dog was

categorized as having a pattern coat colour instead of mixed coat colour. Specific to the black

and tan pattern, black (or blue) had to be listed as the primary colour. In situations where tan

was listed as the primary colour (e.g., tan and black), dogs were categorized as a mixed coat

colour.

Source was how the dog was brought into the shelter and comprised four categories: owner

surrender, stray, shelter offspring, or other. Original source represented how or where the

individual relinquishing the dog had originally obtained the animal, as recorded in the shelter

record. Eight categories in total were used for original source including: free pet, offspring of

owner’s pet, shelter or pound, breeder, rescue, friend or relative, stray or abandoned and other.

There were three other identified original sources (pet shop, veterinarian, and market flyer), that

were included as part of the ‘other’ category as they had a small number of data points. Another

unique variable (i.e., online source) was constructed from information recorded under original

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source in order to differentiate whether an animal was originally acquired through an online

source or not.

Surrender reason was coded into eight categories: accommodation change; behavioural

problems; cost; household animal population; human expectation and lifestyle; owner health or

illness; unwanted animal or litter; other. These categories were based on previously identified

criteria used in a systematic review examining the proportion of dogs surrendered for dog-related

and owner-related reasons (Lambert et al., 2014). The BC SPCA shelter records provided a

maximum of one reason per dog.

Population centre categories were based on Statistics Canada’s definitions of the human

population size for each city of the 34 BC SPCA shelters with a physical location (two of the

shelters have no physical location, all animals surrendered in these locations were fostered).

Based on Statistics Canada’s (2011) criteria, the population centres were arranged into three

categories: small (1,000- 29,999 inhabitants), medium (30,000-99,999 inhabitants) and large

(100,000 and above inhabitants).

Holding capacity represents the overall number of dogs a shelter could hold at any given time.

Shelter type was classified as either “limited” which follows a C4C management style, or “other”

which captured shelters with a municipal contract which are required to keep the shelter open to

strays, though follows the capacity for care management style for all other animals being

surrendered to the shelter.

Statistical Analysis

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Descriptive statistics, including the mean, median, standard deviation, minimum and maximum

for continuous variables and frequencies and percentages for categorical variables, were

estimated for independent variables of interest.

A Cox proportional frailty hazard model was produced to determine the effect of shelter and

animal characteristics on length of stay in the shelter. Shelter (i.e., BC SPCA branch) was

introduced as a frailty. The independent variables assessed for significance in this model

included: 1) sex, 2) age, 3) coat colour, 4) breed, 5) source, 6) original source, 7) online source,

8) surrender reason, 9) incoming year, 10) capacity, 11) shelter type, and 12) population centre.

The linearity assumption between holding capacity and the outcome was assessed by examining

the statistical significance of adding a quadratic term. A causal model was built to assist in

identifying potential confounding variables.

Variables were initially considered for inclusion in the multivariable model based on pre-

screening using univariable analysis with a liberal p-value (α = 0.20). Initially, a main effects

model was fitted. The proportional hazard assumption was examined for each variable using the

proportional hazard test. Variables were modeled as time varying covariates (TVCs) if this

assumption was violated. A significance level of α = 0.05 was used. Due to convergence issues,

interactions could not be assessed. Similarly, while we found the addition of TVCs improved the

fit of the model based on the Bayesian Information Criterion (BIC), the addition of the terms

prevented the generation of residuals.

Descriptive statistics and survival analysis modeling were conducted using STATA (version 13,

StataCorps, 2009).

Results

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Study Population

There were 8,325 dogs that entered a BC SPCA shelter for the first time, eligible for adoption or

euthanasia between January 1st, 2010 and July 31st, 2014, which qualified them for inclusion in

our analysis. There were five shelters that were dropped out of the analysis, two of the shelters

were foster only and had no physical location and the other three had a dog capacity of zero,

therefore a total of 31 shelter branches were included in the following analysis. Table 3.1

provides details on the dog population and shelter characteristics included in the current study.

There were slightly more males (52.1%) than females (47.9%). More adult dogs (75.6%) entered

shelters during the time period than pups (24.3%). Adoption was the most common outcome,

with 7,567 dogs being identified as adopted (90.8%) in the analyzed dataset. The length of stay

ranged from 1 to 472 days with an average of 25.1 days, a median of 14 days and a standard

deviance (SD) of 34.3 days. Mixed breed dogs (n = 8057, 96.8%) entered the shelter system

more frequently than purebred dogs (3.2%). Of the mixed breed dogs, Labrador mixes were the

most common mix to enter the system (14.5%). Incoming dogs were also mainly mixed coloured

(40.1%). Almost all dogs entered the shelter as an owner surrender (97.9%) and were most

commonly surrendered for owner related reasons: unwanted (17.9%), number of household pets

(17.0%), expectation or lifestyle (14.7%), accommodation (12.5%), cost (9.2%), or owner health

or illness (8.3%) compared to animal related reasons: behaviour problems and “other”. Dogs

entering the shelter were most commonly obtained from a friend or relative (28.4%), from

animal control/shelter/pound (15.3%) or a breeder (15.1%). The 31 shelters included in the

current analysis were evenly distributed across the three population centre sizes: small (34.4%),

medium (30.4%) and large (35.2%). Shelters varied in holding capacity, ranging from 2 to 35

dogs with an average capacity of 19.2 dogs (median = 16; SD = 8.2).

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The Effect of Shelter and Animal Characteristics on Length of Stay in the Shelter

Univariable models indicated four non-significant independent variables of interest (source,

source online, shelter capacity and shelter type (p>0.2)), all of which were not considered

through a causal model to be potential confounders of relationships identified in the subsequent

final model. As a result, these four variables were not included in further analysis. Therefore, the

final model included: breed, coat colour, surrender reason, age, original source, population

centres and incoming year. Among these variables, the following variables were modeled as

TVCs since they did not meet the assumption of the proportional hazards: breed, surrender

reason, original source, age, year incoming and population centre.

When age and incoming year were treated as a TVC in the multivariable analysis they became

non-significant and therefore, were no longer treated as TVCs (Table 3.2).

As a TVC, Figure 3.1 shows how the effect of breed changed over time. Relative to the adoption

of Border Collie mixes, the hazard ratio for German Shepherd mixes, Labrador mixes, Shih Tzu

mixes, and other mixes significantly decreased over time. The hazard ratio for purebreds also

decreased over time compared to Border Collie mixes. While Husky mixes had lower hazard

ratio when they entered, the hazard ratio increased over time compared to Border Collie mixes.

This indicates that over time relative to the adoption of Border Collies, time to adoption

increased for German Shepherd mixes, Labrador mixes, Shih Tzu mixes, other mixes and

purebreds, while time to adoption decreased for Husky mixes.

White coat coloured and yellow coat coloured dogs had a significantly higher hazard of being

adopted compared to black coat coloured and patterned coat coloured dogs (Tables 3.2 & 3.3).

Yellow coat coloured dogs also had a significantly higher hazard rate of being adopted compared

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to mixed coat coloured and brown coat coloured dogs (Table 3.3). This indicated that white or

yellow coat coloured dogs had a faster time to adoption compared to black or patterned coat

coloured dogs, and that yellow coat coloured dogs also had a faster time to adoption compared to

mixed or brown coat coloured dogs. Table 3.3 identifies other significant contrasts between coat

colour categories.

Surrender reason was modeled as a TVC. The hazard ratio for dogs surrendered due to cost was

found to significantly increase over time relative to dogs surrendered due to accommodation

change (Figure 3.2). Similarly, relative to accommodation change, the hazard ratios for dogs

surrendered for behavioural problems, unwanted animals or litter, or for other reasons were

found to increase. Dogs surrendered due to household animal population size, human expectation

and lifestyle, or owner health or illness initially had a high hazard ratio which slightly decreased

over time compared to dogs surrendered due to accommodation change. This indicates that

relative to accommodation change the time to adoption decreased for dogs surrendered as a result

of cost, behavioural problems, unwanted animal or litter and other reasons over time, while the

time to adoption increased for dogs surrendered as a result of household animal population size,

expectation and lifestyle, or owner health or illness over time.

Initially dogs that were obtained from the offspring of the owner’s dog had a lower hazard of

adoption compared to dogs obtained from an animal rescue; however, over time the hazard ratio

approached the null (Table 3.3). Relative to dogs obtained from an animal rescue, the hazard

ratio increased over time for dogs that were obtained as stray or abandoned animal, from a friend

or relative, and from other sources. The hazard ratio decreased for dogs obtained from an animal

shelter/pound/control, a breeder, and as a free pet over time compared to dogs sourced from an

animal rescue. These results indicated, that compared to dogs sourced from an animal rescue, the

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time to adoption decreased over time for dogs sourced from the offspring of the owner’s pet, as

stray or abandoned animal, from a friend or relative, or from other sources, while time to

adoption increased over time for dogs sourced from an animal shelter/pound/control, a breeder or

as a free pet (Figure 3.3).

Puppies had a significantly greater hazard of adoption compared to adult dogs (Table 3.2),

indicating that puppies had a shorter time to adoption.

Population centre was modeled as a TVC, and as time increased the hazard ratios were found to

significantly increase for small and medium population centres relative to large population

centres. This indicates that over time, the time to adoption for dogs that entered a shelter located

in a small or medium population centre decreased compared to dogs that entered a shelter located

in a large population centre (Figure 3.4).

Dogs had a significantly lower hazard of adoption in 2010 to 2013 compared to dogs in 2014

(Table 3.2). Dogs that entered a shelter in 2011 had a significantly lower hazard of adoption

than the dogs that entered a shelter in 2010 and 2013 (Table 3.3). This indicates that dogs that

entered the shelter between 2010 and 2013 had a longer length of stay compared to dogs that

entered in 2014, and dogs that entered in 2010 and 2013 also had a shorter length of stay

compared to 2011.

The model with TVCs and without TVCs were compared using BIC, the BIC was smaller for the

model with TVCs (without TVCs BIC = 116651.7, with TVCs BIC = 116421.6).

Discussion

This study is the first, to our knowledge, in North America to use survival analysis to understand

how factors affect time to adoption among dogs in shelters. It is also the first study in Canada

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and one of the first studies in North America to use data from a large sheltering system involving

more than two shelters. The study included 31 different shelters across the province of British

Columbia allowing for a unique evaluation and interpretation of how different factors affect a

dog’s time to adoption across a wide geographical area. Understanding how animal and shelter

characteristics contribute to an animal’s time to adoption offers valuable information upon which

shelters may create targeted adoption promotions to decrease time to adoption and overall

increase the number of animals helped by the shelter.

Not surprisingly, the current study found dogs under a year of age had a decreased time to

adoption compared to dogs one year and older, which is consistent with the results of other

studies (Lepper, Kass and Hart, 2002, Diesel, Smith and Pfeiffer, 2007, DeLeeuw, 2010). As

suggested by other researchers (Diesel, Smith and Pfeiffer’s, 2007), puppies are likely more

appealing to adopters and therefore adopted much faster than mature animals. As a result,

shelters may want to consider investing more of their time and resources in promotions focused

on the adoption of animals older than a year of age to reduce their overall length of stay. As an

example, a number of sheltering organizations have already implemented adopt a senior month

(November); during this month the cost of adopting an elderly animal is decreased (BC SPCA,

2012; OSPCA, 2015; ASPCA, 2015). Continuing to expand these programs among the sheltering

community and looking to develop other promotions to encourage the adoption of adult dogs is

likely to assist with reducing an older animal’s length of stay within a shelter.

Interestingly, the current study did not find that adopters had a preference for sex of dog.

Findings on the role of sex in adopters’ preference for an animal have been inconsistent. A

number of studies have found sex to have a role in adopters preference for an animal (Lepper,

Kass and Hart, 2002; Clevenger and Kass, 2003; Diesel, Smith and Pfeiffer, 2007; DeLeeuw,

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2010); whereas, others have found no difference in adoption between sexes (Brown, Davidson

and Zueffle, 2013; Nĕmcová and Novák, 2003). Due to differences in findings relating to an

animal’s sex and adopters’ preferences, it is likely that shelters in this study population would

gain more from initiatives and resource invested in targeting the promotion of animal related

characteristics more consistently found to have an influence on adoption rates.

In the current study, Shih Tzu mixes were initially more quickly adopted compared to Border

Collie mixes. This result is similar to the research by Lepper, Kass and Hart (2002) and

DeLeeuw (2010), which found the category of lapdogs and toy breeds to be the most popular for

adopters. However, our study found that as time in the shelter increased, Shih Tzu mixes had an

increased time to adoption relative to Border Collies. Unlike previous research, which has found

purebred dogs were significantly more likely to be adopted compared to mixed breed dogs

(Lepper, Kass and Hart, 2002), the current study in general found there was initially no

difference in time to adoption between purebreds and Border Collie mixes, and that the time to

adoption increased over time for purebreds compared to Border Collies mixes. The results from

our study indicated that, as time in shelter increases, breed of the dog seems to have less of an

impact on time to adoption compared to when a dog first enters the shelter. This could suggest

that dogs which have a longer stay in the shelter have other factors affecting their time to

adoption, such as behaviour or health problems, which diminish the effect of breed on adoption

over time. Research into this area is needed, as understanding how time to adoption changes

over time for certain breeds and or breed classifications (e.g. sporting dogs and herding dogs)

may further help shelters to allocate resources toward breeds or breed classifications that are

more challenging to adopt in order to reduce the shelter’s overall length of stay.

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The results of the current study indicate that white and yellow dogs had a significantly shorter

length of stay until adoption compared to black dogs. These results are similar to a study

conducted in the United States that found white, gold and grey dogs are more likely to be

adopted (Posage, Bartlett and Thomas 1998). In addition, a UK study found yellow dogs are

adopted faster compared to black dogs (Diesel, Smith and Pfeiffer, 2007), however this study did

not find a difference between white dogs and black dogs. The study also found that grey/merle

dogs were more quickly adopted compared to black dogs. Further supporting the effect of coat

colour on adoption, Lepper, Kass and Hart (2002) found that black dogs and brindle dogs were

least likely to be adopted. In part, these findings may be related to the association of black and

tan, and brindle coat colours with breeds such as Dobermans, Boxers, Rottweilers and Bull

mastiffs, which have been shown to have a lower preference among adopters (Lepper, Kass and

Hart, 2002; Diesel, Smith and Pfeiffer, 2007; Brown, Davidson and Zueffle, 2013 ). In the

current study, we combined all patterns including brindle, black and tan and merle into one coat

colour category, therefore the effect of specific patterns was not examined. We also found that

dogs with patterned coats had a significantly longer time to adoption compared to brown, mixed,

yellow or white coat coloured dogs. There is a need for further research investigating specific

coat colour patterns on time to adoption, understanding the desirability of coat colour patterns

can aid in developing adoption promotions targeted at decreasing the length of stay for certain

coat colours or patterns found to be less desirable to adopters.

The current study found that initially when the dogs first enter the shelter, dogs surrendered for

behavioural reasons had a higher hazard of adoption compared to dogs surrendered for cost

reasons, but over time this difference became smaller. In contrast, DeLeeuw (2010) found dogs

surrendered due to owner related reasons such as cost and human expectation had a higher

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probability of adoption compared to dogs surrendered due to behavioural problems. Dogs

surrendered due to cost in the current study initially had the longest time to adoption compared to

almost every other surrender reason, although the effect became smaller over time relative to

accommodation change, suggesting that over time the reason why a dog was surrendered has less

of an effect on time to adoption. Since only one reason was provided for relinquishment, it is

possible that dogs surrendered due to cost had secondary issues such as health or injuries that

required extra money or other secondary non-cost related issues that made them less adoptable.

Lepper, Kass and Hart (2002) in their research found that animals surrendered due to health or

injury related issues had decreased odds of adoption, which could be associated with an

increased cost for care. The effect that cost had on time to adoption may decrease over time

suggests that potential adopters felt sympathy for these animals as they have been in the shelter

for a long time. It could also be inherent in that the longer a dog was in the shelter system the

more likely it would eventually be adopted or that shelters are more likely to implement adoption

programs that target these dogs. Further research verifying the success of adoption programs on

time to adoption will assist shelters to know where to dedicate their resources. In the current

study, an animal’s health status could not be investigated, so research investigating how health

affects time to adoption would provide valuable information about the effects of health and

chronic conditions on the adoptability of a dog. Research has found that surrender reasons are

complex and often involve more than one reason (Salman et al., 1998; Scarlett et al., 1999;

Lambert et al., 2014). Allowing individuals relinquishing an animal to provide more than one

reason at the time of surrender may help shelters and researchers better understand the impact of

these issues resulting in relinquishment on time to adoption.

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This is one of the first studies to investigate where a dog was sourced and how it affected the

time to adoption once in a shelter. Interestingly, dogs that were the offspring of the owner’s own

dog had the slowest rate to adoption compared to every other source when a dog first entered the

shelter. As time increased, the time to adoption decreased for these dogs obtained from the

owner’s own dog relative to dogs obtained from an animal rescue. It is possible that these owners

may have attempted selling the pups or keeping the animals for their own before relinquishing.

By the time the dog was relinquished, it is possible the dog was no longer a pup, increasing the

likelihood of a longer length of stay initially. As time increased the origin of the dog had less of a

negative impact on time to adoption. Or the opposite could be possible and that these dogs came

in as very young pups that were too young for adoption, as a result they had to stay longer before

they were even available for adoption. This scenario would explain why as time increased the

effect of original source had less of an impact. Of further interest, the current study found no

difference in time to adoption between dogs originating from online sources and other sources.

Online source was based on an animal being obtained as a result of online ads promoting

available animals from breeders and free pets; future data collection efforts by shelters and

researchers may consider trying to capture more specific details relating to the animal’s

originating online source including whether the owner obtained the animal from a shelter, an

individual or a store as a result of an online ad. As more animals become available online, it may

be important to continue to monitor the effects of online sourcing on adoption rates. A study

conducted by Lampe and Witte (2015) investigated how photos of adoptable dogs posted online

positively impacted the time to adoption and found that the quality of the photo as well as the

characteristics of the dog’s pose can affect time to adoption. Most humane organizations are now

advertising animals available for adoption online; understanding aspects of online promotion of

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an animal that contribute to a dog’s adoptability may be beneficial to shelters in decreasing the

overall length of stay for dogs in their shelter system.

Results of the current study also showed that when a dog first enters a shelter the larger the

human population was where the shelter branch was located the faster a dog was adopted. This

result is likely due to an increased demand for dogs and more individuals visiting shelters in a

community with a larger human population base, but as time increased the relative difference in

time to adoption among the dogs that entered a shelter in a small or medium population centre

decreased. The results from the current study support the development of transfer programs that

move dogs that are having problems being adopted from certain shelters to where the chances of

adoption are likely to be increased. The BC SPCA has implemented a program called Drive for

Lives (BC SPCA, 2013), transferring animals to different branches across the province to

facilitate adoptions which could provide an explanation for the results found. If an adopter wants

to adopt an animal from a non-local branch, Drives for Lives will transfer the animal to the

branch nearest to the adopter. Further research investigating the effects of transfer programs on a

dog’s time to adoption within a shelter is warranted.

In the current study, the differences in time to adoption among different incoming years could be

a result of adoption promotions that were implemented by the BC SPCA. Additionally, dogs

entering the shelters in 2011 had a slower time to adoption compared to dogs entering in 2010

and 2013, which could be due to an observed increase in the number of dog taken in by the BC

SPCA shelter system in that year. The higher time to adoption in years 2010, 2011, 2012 and

2013 compared to 2014 could also be due to the possibility the months that have a decreased

adoption rate were not included for 2014 as intake data were only available until July 31st 2014.

Limitations

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Common trends found between the results of the current study and other studies support the

generalizability of our findings. Further, the current study involved a large shelter system

representing a large region of Canada. However, caution should be taken when generalizing the

results of the current study to other parts of the world or to shelter systems. For example, it is

possible that regional or societal differences may exist in relation to peoples’ preference for dog

breed or coat colour influencing a dog’s length of stay in other shelter systems. In addition,

although the BC SPCA has implemented a number of approaches consistent with the C4C model

for shelter management (e.g., dog flow through), including changes over the course of the current

study (2013-2014), the BC SPCA has not typically experienced a level of dog surrender that

exceeds their shelter capacity. Therefore, they have not needed to implement the intake

management strategies for dogs associated with C4C. Case studies investigating the success of

C4C management have suggested adoptions increase after implementing C4C for cats (CFHS,

2015), future research exploring the role of C4C on time to adoption for dogs in areas

experiencing overpopulation issues would be beneficial. Regardless of the role of C4C in

decreasing a dog’s length of stay, the principles of C4C remain important for shelters to consider

given another focus of the program is on promoting animal welfare by utilizing the five freedoms

(i.e., freedom from pain, injury and disease, freedom from discomfort, freedom from hunger and

thirst, freedom from fear and distress, and freedom to express normal behaviours) as a standard

in order to decrease shelter-animal stress (Karsten, 2014). Future research into the various

outcomes of C4C, for both dogs and cats, would be beneficial for the sheltering community.

Within the current study, interactions between variables were not tested due to the model’s

complexity resulting in model convergence issues. It is possible the inclusion of interaction terms

in the analysis could have provided further information about time to adoption for dogs in the

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shelter system. Residuals could not be generated due to issues associated with model

complexities; however, the lower BIC value for the model with the TVCs supports that the TVCs

should have been included.

The possibility of misclassification bias exists in relation to the current study as it can be

challenging to identify accurately the breed and coat colour of dogs, particularly for mixed

breeds. In addition, certain data were not comparable across all shelters included in the current

study; therefore, it was not possible to examine the association between certain factors and

length of stay in a shelter for dogs (e.g., behaviour assessment). Continued efforts to standardize

data collection across shelter organizations will be important to further research efforts in this

area. As an example, efforts to standardize behavioural assessments across shelters and

investigate how a dog’s behaviour affects length of stay would be valuable. Weight or size of

dogs have also been shown to be factors affecting adoption but were not available in the current

dataset.

Due to the way breed categories were organized for the current study, it is difficult to fully

compare results with other studies. A call has been made for greater standardization of data

collection and definitions among shelters to provide more comparable data among studies

(Lambert et al., 2014), and to minimize the risk of misclassification bias. In the United States

specifically, humane organizations have been working to create standardized shelter data across

the nation. The American SPCA (ASPCA) has also recently released a position statement on

shelter data collection and reporting, stating that there is a need for consistent definitions and

accurate data, which will allow for better comparison to other shelters and more accurate results

(ASPCA, 2016). In addition, Shelter Animals Count (2015) is an American non-profit

organization, which has been recently founded to try to get shelters across the United States to

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create a national database using standardized definitions and reporting for shelter statistics.

Standardizing shelter data on a global scale would allow for the humane community to better

leverage the existing research through knowledge synthesis activities such as systematic review

and meta-analysis. The ability to compare findings across countries is likely to offer a better

understanding of cultural preferences and their impact on different interventions or strategies, as

well as allow for the collection of more accurate information on shelter issues faced around the

world.

Conclusion

A number of factors were associated with a dog’s time to adoption within a provincial shelter

system in Canada. Shelters should continue to consider adoption programs and promotions that

target factors that lengthen a dog’s stay within a shelter system. By targeting these areas, shelters

should be able to decrease a dog’s time to adoption in the shelter system, which should decrease

the animal’s stress and improve their health and their experience while in the shelter. In shelters,

decreasing time to adoption will ultimately lead to an increase in the number animals helped by

the shelter. In Canadian shelters, cat intake and euthanasia is higher compared to dogs (CFHS,

2013), future research examining factors associated with cats’ length of stay within a shelter

system will further support shelters and cats by decreasing euthanasia and increasing the number

of cats adopted.

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Reeve, C. L., Rogelberg, S. G., Spitzmüller, C., & DiGiacomo, N. (2005). The caring-killing

paradox: Euthanasia-related strain among animal-shelter workers. Journal of Applied Social

Psychology, 35, 119-143.

Rogelberg, S. G., Reeve, C. L., Spitzmüller, C., DiGiacomo, N., Clark, O. L., Teeter, L., …

Carter, N. T. (2007). Impact of euthanasia rates, euthanasia practices, and human resource

practices on employee turnover in animal shelters. Journal of the American Veterinary Medical

Association, 230, 713-719

Salman, M. D., New, J. G., Scarlett, J. M., Kass, P. H., Ruch-Gallie, R., & Hetts, S. (1998).

Human and animal factors related to the relinquishment of dogs and cat in 12 selected animal

shelters in the United States. Journal of Applied Animal Welfare Science, 1, 207-226.

Scarlett, J. M., Salman, M. D., New, J. G., & Kass, P. H. (1999). Reasons for relinquishment of

companion animals in the U.S. animal shelters: selected health and personal issues. Journal of

Applied Animal Welfare Science, 2, 41-57.

Shelter Animals Count. (2015). Retrieved from http://www.shelteranimalscount.org/

Turner, P., Berry, J., & MacDonald, S. (2012). Animal shelters and animal welfare: raising the

bar. The Canadian Veterinary Journal, 53, 893.

116

White, D. J., & Shawhan, R. (1996). Emotional responses of animal shelter workers to

euthanasia. Journal of the American Veterinary Medical Association, 208, 846-849.

117

TABLE 3.1

Descriptive Statistics of Categorical Independent Variables on Dog and Shelter Characteristics

among 31 BC SPCA Shelters, January 2010– July 2014.

Variable No. %

Sex (n= 8,319)

Female 3,984 47.89

Male 4,335 52.11

Age (n=8,325)

Adult 6,297 75.64

Pup 2,028 24.36

Breed (n=8,325)

Purebred 268 3.22

Border Collie Mix 517 6.21

German Shepherd Mix 914 10.98

Husky Mix 457 5.49

Labrador Mix 1,202 14.44

Shih Tzu Mix 419 5.03

Other Mix 4,548 54.63

Coat Colour (n=8,289)

Black 895 10.80

Brown 979 11.81

Grey 115 1.39

White 413 4.98

Yellow 672 8.11

Mixed 3,309 39.92

Patterned 1,906 22.99

Source (n=8,325)

118

Owner Surrender 8,155 97.96

Stray 91 1.09

Shelter Offspring 63 0.76

Other 16 0.19

Original Source (n=8,325)

Friend or Relative 2,362 28.37

Breeder 1,256 15.09

Animal Shelter or Control / Pound 1,275 15.32

Offspring of Owner’s Pet 819 9.84

Free Pet 722 8.67

Animal Rescue Organization 686 8.24

Stray or Abandoned Animal 917 11.02

Other 288 3.46

Online ad (n=8,325)

Yes 890 10.69

No 7,435 89.31

Surrender Reason (n=8,114)

Household Animal Population 1,383 17.04

Unwanted Animal or Litter 1,452 17.89

Accommodation Change 1,014 12.50

Human Expectation and Lifestyle 1,196 14.74

Cost 745 9.18

Owner Health or Illness 673 8.29

Behavioural Problems 672 8.28

Other 979 12.07

Population Centre Size (n=8,325)

Large 2,929 35.18

Medium 2,532 30.41

119

Small 2,864 34.40

Outcome

Adopted 7,823 92.44

Euthanized 640 7.56

Available for Adoption 6 0.07

Escaped 1 0.01

In shelter 99 1.19

Stolen 4 0.05

Unassisted Death 26 0.31

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TABLE 3.2

Cox Proportional Frailty Hazard Main Effects Model including the Time Varying Components

of 8325 dogs that Entered the BC SPCA Shelter System between January 2010 and July 2014.

Variable Coefficients Standard Error 95% C.I. p-value

Breed

Border Collie Mix Referent

German Shepherd Mix 0.272 0.167 -0.056, 0.600 0.104

Husky Mix -0.3685 0.208 -0.776, 0.039 0.076

Labrador Mix 0.268 0.161 -0.049, 0.584 0.097

Other Mix 0.269 0.146 -0.016, 0.554 0.065

Purebred 0.114 0.230 -0.336, 0.565 0.619

Shih Tzu 0.501 0.198 0.113, 0.889 0.011*

Coat Colour

Black Referent

Brown 0.062 0.051 -0.038, 0.161 0.223

Grey 0.125 0.107 -0.084, 0.334 0.242

Mixed 0.068 0.042 -0.014, 0.151 0.104

Patterned -0.043 0.045 -0.132, 0.046 0.346

White 0.175 0.066 0.046, 0.305 0.008*

Yellow 0.205 0.055 0.098, 0.312 0.000*

Surrender Reason

Accommodation

Change

Referent

Behaviour Problems -0.095 0.145 -0.383, 0.192 0.516

Cost -0.872 0.155 -1.176, -0.569 0.000*

Household Animal

Population

0.070 0.127 -0.179, 0.318 0.583

Human Expectation /

Lifestyle

0.180 0.121 -0.058, 0.418 0.139

Other -0.245 0.137 -0.514, 0.025 0.075

Owner Health or

Illness

0.066 0.140 -0.209, 0.341 0.637

Unwanted Animal or

Litter

-0.144 0.126 -0.391, 0.102 0.251

Original Source

Animal Rescue Referent

Animal Shelter or

Control / Pound

0.145 0.124 -0.098, 0.389 0.242

Breeder 0.038 0.138 -0.233, 0.309 0.784

Free Pet -0.173 0.159 -0.484, 0.138 0.274

Friend or Relative -0.201 0.127 -0.451, 0.048 0.114

Offspring of Owner’s

Pet

-0.740 0.163 -1.060, -0.420 0.000*

Other -0.098 0.208 -.505, 0.309 0.637

121

Stray or Abandoned

Animal

-0.225 0.145 -0.509, 0.060 0.121

Age

Adult Referent

Pup 0.297 0.032 0.235, 0.358 0.000*

Population Centres

Large Referent

Medium -0.958 0.124 -1.201, -0.716 0.000*

Small -1.407 0.122 -1.646, -1.167 0.000*

Year Incoming

2010 -0.117 0.048 -0.213, -0.022 0.016*

2011 -0.216 0.044 -0.302, -0.130 0.000*

2012 -0.173 0.044 -0.258. -0.087 0.000*

2013 -0.124 0.044 -0.211, -0.037 0.005*

2014 Referent

TVCS

Breed

Border Collie Mix Referent

German Shepherd Mix -0.134 0.058 -0.247, -0.0206 0.021*

Husky Mix 0.036 0.0703 -0.102, 0.174 0.611

Labrador Mix -0.140 0.0555 -0.249, -0.031 0.012*

Other Mix -0.123 0.0500 -0.221, -0.025 0.014*

Purebred -0.090 0.078 -0.243, 0.0622 0.246

Shih Tzu -0.140 0.071 -0.278, -0.001 0.048*

Surrender Reason

Accommodation Change Referent

Behaviour Problems 0.012 0.052 -0.089, 0.113 0.816

Cost 0.129 0.050 0.0308, 0.227 0.010*

Household Animal

Population

-0.053 0.045 -0.141, 0.034 0.232

Human Expectation /

Lifestyle

-0.058 0.043 -0.143, 0.028 0.185

Other 0.0593 0.047 -0.033, 0.152 0.207

Owner Health or Illness -0.035 0.050 -0.133, 0.063 0.483

Unwanted Animal or

Litter

0.030 0.044 -0.055, 0.116 0.489

Where the Animal was

Obtained

Animal Rescue Referent

Animal Shelter or

Control / Pound

-0.080 0.046 -0.170, 0.011 0.083

Breeder -0.029 0.050 -0.127, 0.069 0.562

Free Pet -0.013 0.056 -0.123, 0.096 0.810

Friend or Relative 0.042 0.460 -0.048, 0.132 0.363

Offspring of Owner’s Pet 0.217 0.057 0.106, 0.328 0.000*

Other 0.080 0.076 -0.069, 0.229 0.293

122

Stray or Abandoned

Animal

0.066 0.052 -0.037, 0.168 0.208

Population Centres

Large Referent

Medium 0.339 0.030 0.281, 0.397 0.000*

Small 0.415 0.030 0.357, 0.474 0.000*

123

TABLE 3.3

Significant Categorical Variable Contrasts of the Cox Proportional Frailty Hazard Model of the

8235 Dogs that entered the BC SPCA Shelter System between January 2010 and July 2014

Variable Hazard Ratio Standard Error 95% C.I. p-value

Coat Colour

Yellow vs. Black 1.228 0.067 1.103, 1.367 0.000

White vs Black 1.192 0.079 1.047, 1.357 0.008

Brown vs. Patterned 1.110 0.048 1.020, 1.208 0.015

Brown vs. Yellow 0.866 0.047 0.779, 0.963 0.008

Mixed vs Patterned 1.117 0.035 1.050, 1.189 0.000

Mixed vs Yellow 0.872 0.040 0.797, 0.954 0.003

Patterned vs. White 0.804 0.048 0.715, 0.904 0.000

Patterned vs. Yellow 0.780 0.038 0.709, 0.859 0.000

Incoming Year

2014 vs. 2010 0.889 0.044 0.808, 0.978 0.016

2014 vs. 2011 0.806 0.036 0.739, 0.879 0.000

2014 vs. 2012 0.841 0.367 0.772, 0.916 0.000

2014 vs. 2013 0.883 0.039 0.810, 0.963 0.005

2010 vs. 2011 1.104 0.044 1.021, 1.193 0.013

2011 vs. 2013 0.912 0.032 0.852, 0.976 0.008

124

Figure 3.1

Hazard ratios of the breed categories against the natural log (ln) of time illustrating the changing

time to adoption of various breed categories relative Border Collie mixes.

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

0 1 2 3 4 5 6 7

Haz

ard

Rat

io

Ln(days)

Breed TVC

German Shepherd Mix Husky Mix Labrador Mix Other Mix Purebred Shih Tzu Mix

125

Figure 3.2

Hazard ratios of the surrender reasons against the natural log of time illustrating the changing

time to adoption of various surrender reason categories relative to accommodation change.

0

0.2

0.4

0.6

0.8

1

1.2

1.4

0 1 2 3 4 5 6 7

Haz

ard

Rat

io

Ln(days)

Surrender Reason TVC

Behaviour problems Cost Household animal population

Expectation and lifestyle Other Owner health or illness

Unwanted

126

Figure 3.3

Hazard ratios of the original sources against the natural log of time illustrating the changing time

to adoption of various original source categories relative to animal rescue.

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

0 1 2 3 4 5 6 7

Haz

ard

Rat

io

Ln(days)

Original Source TVC

Shelter/control/pound Breeder Free Friend or relative

Offspring of pet Other Stray or abandoned

127

Figure 3.4

Hazard rations of the population centres where the shelters are located the natural of time

illustrating the changing time to adoption of various population centre categories relative to large

population centres

0

0.5

1

1.5

2

2.5

3

3.5

0 1 2 3 4 5 6 7

Haz

ard

Rat

io

Ln(days)

Population Centre TVC

Pop Centre - Med Pop Centre - Small

128

CHAPTER FOUR

Conclusions

129

Companion animal population dynamics is multifaceted with a variety of factors that can impact

it including: ownership practices, reproduction, control practices, relinquishment and

abandonment. Research has demonstrated that human socioeconomic factors (Eze and Eze,

2002; Farnworth et al., 2012; Flockhart, Norris and Coe, 2016), cultural values and religion

(Fielding and Mather, 2001; Hsu, Severinghaus and Serpell, 2003; McNicholas et al., 2005;

Fielding, 2010a; Fielding, 2010b), laws (Winter, 2004; Voslářá and Passantino, 2012) and

climate (Gunther and Terkel, 2002; Ortega-Pacheco et al., 2007; Finkler and Terkel, 2012) all

have the ability to influence companion animal population dynamics different contexts. Different

combinations of these factors can also affect the magnitude of companion animal population

dynamics, resulting in different research interests and priorities.

As a result of the impacts companion animal population dynamics has on a number of different

areas, companion animal population dynamics receives attention from many different

stakeholders, including: animal welfare professionals, ecologists/conservationists and public

health professionals. Among these stakeholders a variety of different control practices have been

investigated and applied in practice, often based on the desired outcome of interest, to control the

free roaming (unowned and owned) and unwanted companion animal populations. Research has

identified that different stakeholders view the issues differently and for the most part have

different outcomes of interest. For example, studies investigating stakeholders’ views found that

TNR groups were less likely to believe free roaming cats posed a threat to native species and to

the environment compared to ecologists/conservationists (Wald, 2012).

Ecologists/conservationists were also more likely to support euthanasia as a control practice

compared to TNR groups and animal welfare professionals (Wald, 2012; Lohr and Lepczyk,

2014).

130

Animal shelters are also impacted by free roaming and unwanted companion animal populations

as a result of relinquishment, abandonment, and the surrendering of stray animals, which can

lead to overcrowding. Overcrowding can result in increased stress and spread of disease (Hurley,

2005) and can also lead to unnecessary euthanasia. Euthanizing animals can negatively affect

shelter workers by causing them extreme stress (White and Shawhan, 1996; and Gardner, 2008).

As a result, the shelter community has begun to explore and implement control methods to try to

mitigate the impacts of overcrowding within animal shelters, most recently by focusing on

decreasing length of stay and limiting admissions (Hurley, 2005).

As many shelters are interested in decreasing length of stay, understanding factors that influence

adoption and subsequently length of stay, is extremely important. Previous studies have indicated

that breed, age, size, sex, coat colour, and surrender reason can all impact adoption. Puppies

under a year of age, females, small dogs, and purebreds have been shown to be preferred by

adopters (Lepper, Kass and Hart, 2002; Diesel, Smith and Pfeiffer, 2007; DeLeeuw, 2010), while

dogs surrendered due to animal related reasons such as behaviour and health were less likely to

be adopted compared to dogs surrendered due to owner related reasons (Lepper, Kass and Hart,

2002; DeLeeuw, 2010).

The purpose of this thesis was to assimilate the breadth and depth of research published on

companion animal population dynamics by using a systematic process that was both rigorous and

transparent. This thesis also provides results on the first Canadian study investigating factors that

impact a dog’s time to adoption in a large, multi-shelter system.

Summary of Findings

131

There are two studies that comprise this thesis: (1) a scoping review of the published research on

the population dynamics and control practices of companion animals and (2) a survival analysis

examining factors that affect a dog’s time to adoption within an animal shelter.

A Scoping Review of the Published Research on the Population Dynamics and Control Practices

of Companion Animals

The focus of the scoping review was to summarize the current state of knowledge on approaches

to managing companion animal population dynamics to control the number of owned free-

roaming, un-owned free-roaming and unwanted companion animals. The scoping review found

869 published articles (450 primary research and 419 reviews) that investigated or provided

commentary on population dynamics, surveillance and or control practices relating to companion

animals. Journal articles were the most common document type published and most of the

research was conducted in or discussed the topic within the context of the United States. An

increasing amount of articles have been published over the years, most research was conducted

after 2000, with 25% of the articles being published between 2012 and June 2015. This indicates

that the topic of companion animal population dynamics and the control practices used are highly

discussed and many stakeholders are interested in this topic. Dogs and cats were the main

companion animals investigated with cats having a slightly higher focus than dogs. Unowned

free roaming companion animals was the main type of population studied within the articles. The

majority of the articles investigated control practices, specifically different methods of

reproductive control, and methods of euthanasia. The main outcome of interest was improving

the methodology of control practices. Other main outcomes of interest were views and opinions

on free roaming and unwanted companion animals or control practices used to manage them and

the free roaming and unwanted companion animal population size. Most articles (primary

132

research and reviews) reported or discussed the effectiveness of the control practices investigated

with a main focus on TNR, zona pellucida immunocontraception, and chemical castration

indicating an opportunity for future SR-MAs to be conducted on these specific control practices

to determine their overall effectiveness. Most authors recommended further research or further

development of control practices; reproduction control; control of the free roaming and or

unwanted companion animal populations; or increasing public education. The call for public

education by authors indicates that education is considered an important control practice,

however little primary research has been conducted to determine its effectiveness and the

number of primary research investigating its effectiveness has actually decreased over the years.

Of the primary research articles included, many were observational studies, specifically cross

sectional studies, and the next main study design used was routine surveillance. Study design

changed depending on the control practice investigated, experimental studies were more

commonly used when investigating reproduction control while observational studies were more

commonly used when investigating different methods of euthanasia. Quantitative questionnaires

or surveys and observations or field visits were the most common methods of data collection.

Primary research studies focusing mainly on surveillance (i.e., estimates of population size) have

approximately doubled since 2009. Data were commonly reported as a prevalence outcome,

allowing for the opportunity of future SR-MAs to be conducted. P-values and measures of

variability were commonly reported. The majority of primary research articles identified at least

one weakness and/or one strength of the study.

Factors Influencing Time to Adoption for Dogs in a Provincial Shelter System in Canada

The second study, comprising this thesis, used a Cox proportional hazard frailty model to

determine which factors (animal characteristics, animal source or shelter demographics) affect a

133

dog’s length of stay until adoption in shelters managed by the BC SPCA between January 1st,

2010 and July 31st, 2014. The data included 8,325 dogs that entered the shelter during this time

period, with a majority of the dogs over a year of age and a relatively even proportion of male

and female dogs. Dogs of mixed breeds and dogs with mixed coat colour were the most common

types of dog that entered the shelter system. The most common original source of a dog in the

BC SPCA system was through a friend or relative, and dogs were mainly surrendered due to

owner related reasons (e.g. accommodation, expectation or lifestyle, unwanted or number of

household population). The majority of dogs included in the study entered the BC SPCA shelter

system by owner surrender. The 31 BC SPCA shelters contributing data to the current study were

evenly located across small (1,000- 29,999 inhabitants), medium (30,000-99,999 inhabitants) and

large (100,000 and above inhabitants) human population centres. The shelter holding capacity for

the 31 shelters ranged from 2 to 35 dogs (mean 19.2 dogs; median 16 dogs). The majority of

dogs included in the study were adopted, and the average length of stay was 25.1 days (median

14 days; range 1-472 days).

The multivariable Cox proportional frailty hazard model indicated that age, breed, coat colour,

surrender reason, original source, human population centre size and incoming year were all

found to impact a dog’s time to adoption (p<0.05). Time varying components were included for

the variables: breed, surrender reason, original source and human population centres, as these

variables violated the assumption of the proportional hazard test (i.e. the relative difference in

time to adoption does not remain constant).

Pups under a year of age had a shorter length of stay until adoption compared to adult dogs. Shih

Tzu mixes had a decreased time to adoption compared to Border Collie Mixes when they first

enter the shelter. As time increased, the time to adoption increased for Shih Tzu mixes, Labrador

134

mixes, German Shepherd mixes compared to Border Collie mixes. Husky mixes had the longest

stay in the shelters prior to adoption compared to all other breeds when the dogs first enter the

shelter. As time increased, the time to adoption decreased for Husky mixes relative to Border

Collie mixes. Dogs with yellow coat colours had a shorter time to adoption compared to black,

brindle, mixed or brown coat coloured dogs. As well, white coat coloured dogs had a shorter

time to adoption compared to black or patterned coat coloured dogs. When a dog first entered the

shelter, cost as a surrender reason had a negative impact on time to adoption compared to

surrender due to accommodation changes. As time increased, the time to adoption due to cost

decreased. Dogs obtained from the offspring of the surrendering owner’s dog initially had an

increased time to adoption compared to all of the other original sources. As time increased the

time to adoption decreased for dogs obtained from the offspring of the surrendering owner’s dog

compared to dogs sourced from animal rescues. The human population size of where the shelter

was located also influenced time to adoption. Dogs brought into shelters located in larger

population centres had a shorter time to adoption compared to dogs brought into shelters located

in smaller population centres. As time increased, the time to adoption for dogs brought into

shelters located in small and medium population centres decreased relative to dogs brought into

shelters located in large populations. Understanding which risk factors contribute to a slower

time to adoption and how this may change over time, allows shelters to use this information to

develop adoption programs that could decrease time to adoption for these dogs.

Key Recommendations

The findings of this thesis form a foundation for various key recommendations:

135

Further knowledge synthesis efforts should be considered to determine the efficacy of

control practices, with a specific opportunity to focus on non-surgical reproduction

control methods.

Other control practices for managing free roaming (unowned and owned) and unwanted

companion animals should be researched to provide more information on their

effectiveness such as education and legislations.

Educational programs should be developed to improve knowledge on pet care and

ownership, as well as inform individuals about the issues relating to free roaming

companion animals.

Standardization of shelter data collection and recording should be pursued to enhance

research opportunities and compare shelter information at local, national and

international levels.

Animal characteristics as well as shelter characteristics should be considered when

creating programs to reduce time to adoption.

Shelters should continue to evaluate adoption programs and promotions, specifically

assessing and targeting characteristics that currently increase time to adoption (e.g.,

Adopt-a-Senior Month).

Future studies should be focused on determining how effective current adoption

programs and promotions are at improving time to adoptions.

Thesis Limitations

Limitations were present in both studies comprising this thesis. The results from the scoping

review indicated that free roaming and unwanted companion animals are a global issue as 509

articles of the 869 articles included were conducted outside of the United States or Canada.

136

However, due to the language restrictions, only articles published in English and Spanish were

included in the review, signifying that some relevant articles in other languages could have been

excluded (n=166). However, this scoping review included a large number of articles, articles

excluded as result of the language restriction likely did not have a considerable effect on the

results. In addition, a small number of articles (n=20) identified by the search strategy were not

retrievable and therefore, relevance could not be confirmed. The number of articles excluded

because they could not be obtained was small, suggesting they had limited impact on the results

of the scoping review.

Due to the complexity of the Cox proportional frailty hazard model, variable interactions were

not assessed. Therefore, it is possible that the inclusion of interaction terms could have provided

more information on factors affecting a dog’s time to adoption. Misclassification bias could also

be present within the model due to the difficulty of accurately determining the breeds and coat

colours of the dogs entering the shelters. As well, certain data could not be included in the model

as a result of different data keeping practices across the BC SPCA shelters.

Future Directions for Research

This thesis identifies numerous areas for future research. There is an opportunity for further

knowledge synthesis efforts investigating the effectiveness of control practices used to manage

free roaming (owned and unowned) and unwanted companion animals. More specifically, a

systematic review and meta-analysis (SR-MA) focused on TNR, non-surgical reproduction

control (ZP immunocontraception and chemical castration) or poison (for eradication) should be

prioritized. The research on non-surgical reproduction control types were mainly conducted

through controlled trials, thus providing the best opportunity for future SR-MAs. Further

137

knowledge synthesis efforts will aid in determining the efficacy of these control practices and

ultimately contribute to informing the development of successful control programs.

Continued research on other control practices will help determine if they could be used in future

control programs and aid in the development of evidence-based policies surrounding free

roaming and unwanted companion animals. As many of the studies included in the scoping

review recommended increasing public education, more research is needed to determine how

effective education programs can be used to manage free roaming (owned and unowned) and

unwanted companion animals.

A small number of primary research articles used mathematical models to determine the effects a

control practice will have on the free roaming and unwanted companion animal populations.

Development of mathematical models could inform how to best use resources, therefore saving

resources from being invested in unsuccessful control practices. Further research validating

mathematical models for predicting the effectiveness of control practices is needed.

This thesis has shown that animal characteristics play an important role in determining how

quickly a dog in a shelter will get adopted. Further research investigating the impact of dog

behaviour, dog health and dog size have on time to adoption within a shelter or shelter system

will enhance the understanding on which characteristics shelters should target when creating

adoption promotions. Adoption promotions should target characteristics that have been shown to

lead to a longer length of stay prior to adoption. Decreasing time to adoption could aid in

improving the animals’ welfare by decreasing stress and decreasing disease spread, ultimately

improving the animals’ experience in the shelter.

138

Shelters have implemented many different adoption programs in an attempt to increase adoptions

and reduce animals’ time in shelters. Further research investigating the impact of these adoption

programs at the shelter as well as the community-animal level is needed. Shelters have limited

resources, therefore understanding how successful these programs are will inform shelters where

they should apply their resources.

In Canada and the United States, cats enter shelters more frequently than dogs. Therefore, it is

recommend that a similar study investigating factors that affect time to adoption for cats should

be conducted. Understanding factors which influences time to adoption for cats should help

shelters to increase the number of cats adopted.

139

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dogs and cats in a California animal shelter. Journal of Applied Animal Welfare Science, 5, 29-

42.

140

Lohr, C. A., & Lepczyk, C. A. (2014). Desires and management preferences of stakeholders

regarding feral cats in the Hawaiian Islands. Conservation Biology, 28, 392-403.

McNicholas, J., Gilbey, A., Rennie, A., Ahmedzai, S., Dono, J., & Ormerod, E. (2005). Pet

ownership and human health: A brief review of evidence and issues. BMJ, 331, 1252-1255.

Newbury, S., Blinn, M. K., Bushby, P. A., Cox, C. B., Dinnage, J. D., Griffin, B., … Spindel, M.

(2010). Guidelines for standards of care in animal shelters.

Ortega-Pacheco, A., Segura-Correa, J. C., Jimenez-Coello, M., & Linde Forsberg, C. (2007).

Reproductive patterns and reproductive pathologies of stray bitches in the tropics.

Theriogenology, 67, 382-390.

Voslářá, E., & Passantino, A. (2012). Stray dog and cat laws and enforcement in Czech Republic

and in Italy. Annali dell’Istituto Superiore di Sanità, 48, 97-104.

Wald, D. (2015). Understanding stakeholder conflict: An analysis of public values, risk

perceptions and attitudes toward outdoor cat management (Doctoral Dissertation). University of

Florida.

White, D. J., & Shawhan, R. (1996). Emotional responses of animal shelter workers to

euthanasia. Journal of the American Veterinary Medical Association, 208, 846-849.

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American Veterinary Medical Association, 225, 1369-1376.

141

APPENDIX A

A Scoping review of published research on the population dynamics and control practices

of companion animals

A.1: Database Specific Search Strategies

A.2: Relevance Screening Form

A.3: Data Extraction and Characterization Form

A.4: Reference List of Included 869 Articles

A.5: Description of Non-English Articles Excluded from the Study

A.6: Description of Articles that were Unable to be Obtained

142

A.1.

Database Specific Search Strategies

CAB Direct

title:(("companion animal" OR dog OR cat OR

pet OR canine OR feline) AND

(overpopulation OR population* OR surplus)

AND (homeless OR abandon* OR stray* OR

unowned OR unwanted OR feral OR free-

roaming OR roaming OR (reproduc* OR

breed* OR fertil* OR "birth rate" OR "puppy

mills") OR ("animal control" OR "animal

management" OR euthan* OR shelter* OR

rescue* OR "animal welfare" OR sterilization

OR spay OR neuter OR castration OR

ovariohysterectomy OR orchiectomy))) OR

ab:(("companion animal" OR dog OR cat OR

pet OR canine OR feline) AND

(overpopulation OR population* OR surplus)

AND (homeless OR abandon* OR stray* OR

unowned OR unwanted OR feral OR free-

roaming OR roaming OR (reproduc* OR

breed* OR fertil* OR "birth rate" OR "puppy

mills") OR ("animal control" OR "animal

management" OR euthan* OR shelter* OR

rescue* OR "animal welfare" OR sterilization

OR spay OR neuter OR castration OR

ovariohysterectomy OR orchiectomy))) OR

subject:(("companion animal" OR dog OR cat

OR pet OR canine OR feline) AND

(overpopulation OR population* OR surplus)

AND (homeless OR abandon* OR stray* OR

unowned OR unwanted OR feral OR free-

roaming OR roaming OR (reproduc* OR

breed* OR fertil* OR "birth rate" OR "puppy

mills") OR ("animal control" OR "animal

management" OR euthan* OR shelter* OR

rescue* OR "animal welfare" OR sterilization

OR spay OR neuter OR castration OR

ovariohysterectomy OR orchiectomy)))

Medline (Pubmed)

("companion animal" OR "companion

animals" OR dog OR dogs OR cat OR cats OR

canine OR feline OR pet OR pets) AND

(overpopulation OR population* OR surplus)

AND ((homeless OR abandon* OR stray* OR

143

unowned OR unwanted OR feral OR free-

roaming OR roaming) OR (reproduc* OR

breed* OR fertil* OR "birth rate" OR "puppy

mills") OR ("animal control" OR "animal

management" OR euthan* OR shelter* OR

rescue* OR animal-welfare OR sterilization

OR spay OR neuter OR castration OR

ovariohysterectomy))

Agricola - ProQuest

("companion animal" OR "companion

animals" OR dog OR cat OR canine OR feline

OR pet) AND (overpopulation OR population*

OR surplus) AND (homeless OR abandon* OR

stray* OR unowned OR unwanted OR feral

OR free-roaming OR roaming OR (reproduc*

OR breed* OR fertil* OR "birth rate" OR

"puppy mills") OR ("animal control" OR

"animal management" OR euthan* OR shelter*

OR rescue* OR "animal welfare" OR

sterilization OR spay OR neuter OR castration

OR ovariohysterectomy))

PsycINFO APA PsycNET

("companion animal" OR "companion

animals" OR dog OR dogs OR cat OR cats OR

canine OR feline OR pet OR pets) AND

(overpopulation OR population* OR surplus)

AND (homeless OR abandon* OR stray* OR

unowned OR unwanted OR feral OR free-

roaming OR roaming OR (reproduc* OR

breed* OR fertil* OR "birth rate" OR "puppy

mills") OR ("animal control" OR "animal

management" OR euthan* OR shelter* OR

rescue* OR "animal welfare" OR sterilization

OR spay OR neuter OR castration OR

ovariohysterectomy))

Scopus

(TITLE-ABS-KEY((cat OR dog OR pet OR

"companion animal" OR feline OR canine))

AND TITLE-ABS-KEY((overpopulation OR

population* OR surplus)) AND TITLE-ABS-

KEY((homeless OR abandonment OR stray*

OR unowned OR unwanted OR feral OR free-

roaming)) OR TITLE-ABS-KEY((cat OR dog

OR pet OR “companion animal” OR feline OR

canine)) AND TITLE-ABS-

KEY((overpopulation OR population* OR

144

surplus)) AND TITLE-ABS-KEY((reproduc*

OR breed* OR fertil* OR (birth W/1 rate) OR

(puppy W/1 mill*))) OR TITLE-ABS-

KEY((cat OR dog OR pet OR "companion

animal" OR feline OR canine)) AND TITLE-

ABS-KEY((overpopulation OR population*

OR surplus)) AND TITLE-ABS-KEY((animal

W/1 control) OR (animal W/1 management)

OR euthan* OR shelter* OR rescue* OR

welfare OR sterilization OR spay OR neuter

OR castration OR ovariohysterectomy OR

orchiectomy))

New search adding terms “growth rate”, lambda, or “carrying capacity”

Agricola

("companion animal" OR "companion

animals" OR dog OR cat OR canine OR feline

OR pet) AND ("growth rate" OR lambda OR

"carrying capacity") AND (homeless OR

abandon* OR stray* OR unowned OR

unwanted OR feral OR free-roaming OR

roaming OR (reproduc* OR breed* OR fertil*

OR "birth rate" OR "puppy mills") OR

("animal control" OR "animal management"

OR euthan* OR shelter* OR rescue* OR

"animal welfare" OR sterilization OR spay OR

neuter OR castration OR ovariohysterectomy))

Medline (PubMed)

(("companion animal" OR "companion

animals" OR dog OR dogs OR cat OR cats OR

canine OR feline OR pet OR pets) AND

(growth-rate OR lambda OR "carrying

capacity") AND ((homeless OR abandon* OR

stray* OR unowned OR unwanted OR feral

OR free-roaming OR roaming) OR (reproduc*

OR breed* OR fertil* OR "birth rate" OR

"puppy mills") OR ("animal control" OR

"animal management" OR euthan* OR shelter*

OR rescue* OR animal-welfare OR

sterilization OR spay OR neuter OR castration

OR ovariohysterectomy)))

PsycINFO

145

("companion animal" OR "companion

animals" OR dog OR dogs OR cat OR cats OR

canine OR feline OR pet OR pets) AND

("growth rate" OR lambda OR "carrying

capacity") AND (homeless OR abandon* OR

stray* OR unowned OR unwanted OR feral

OR free-roaming OR roaming OR (reproduc*

OR breed* OR fertil* OR "birth rate" OR

"puppy mills") OR ("animal control" OR

"animal management" OR euthan* OR shelter*

OR rescue* OR "animal welfare" OR

sterilization OR spay OR neuter OR castration

OR ovariohysterectomy))

CabDirect

(title:(("companion animal" OR dog OR cat

OR pet OR canine OR feline) AND ("growth

rate" OR lambda OR "carrying capacity")

AND (homeless OR abandon* OR stray* OR

unowned OR unwanted OR feral OR free-

roaming OR roaming OR (reproduc* OR

breed* OR fertil* OR "birth rate" OR "puppy

mills") OR ("animal control" OR "animal

management" OR euthan* OR shelter* OR

rescue* OR "animal welfare" OR sterilization

OR spay OR neuter OR castration OR

ovariohysterectomy OR orchiectomy))) OR

ab:(("companion animal" OR dog OR cat OR

pet OR canine OR feline) AND ("growth rate"

OR lambda OR "carrying capacity") AND

(homeless OR abandon* OR stray* OR

unowned OR unwanted OR feral OR free-

roaming OR roaming OR (reproduc* OR

breed* OR fertil* OR "birth rate" OR "puppy

mills") OR ("animal control" OR "animal

management" OR euthan* OR shelter* OR

rescue* OR "animal welfare" OR sterilization

OR spay OR neuter OR castration OR

ovariohysterectomy OR orchiectomy))) OR

subject:(("companion animal" OR dog OR cat

OR pet OR canine OR feline) AND ("growth

rate" OR lambda OR "carrying capacity")

AND (homeless OR abandon* OR stray* OR

unowned OR unwanted OR feral OR free-

roaming OR roaming OR (reproduc* OR

breed* OR fertil* OR "birth rate" OR "puppy

mills") OR ("animal control" OR "animal

146

management" OR euthan* OR shelter* OR

rescue* OR "animal welfare" OR sterilization

OR spay OR neuter OR castration OR

ovariohysterectomy OR orchiectomy))))

Scopus

(TITLE-ABS-KEY((cat OR dog OR pet OR

"companion animal" OR feline OR canine))

AND TITLE-ABS-KEY(("growth rate" OR

lambda OR "carrying capacity")) AND TITLE-

ABS-KEY((homeless OR abandonment OR

stray* OR unowned OR unwanted OR feral

OR free-roaming)) OR TITLE-ABS-KEY((cat

OR dog OR pet OR “companion animal” OR

feline OR canine)) AND TITLE-ABS-

KEY(("growth rate" OR lambda OR "carrying

capacity")) AND TITLE-ABS-

KEY((reproduc* OR breed* OR fertil* OR

(birth W/1 rate) OR (puppy W/1 mill*))) OR

TITLE-ABS-KEY((cat OR dog OR pet OR

"companion animal" OR feline OR canine))

AND TITLE-ABS-KEY(("growth rate" OR

lambda OR "carrying capacity")) AND TITLE-

ABS-KEY(((animal W/1 control) OR (animal

W/1 management) OR euthan* OR shelter*

OR rescue* OR welfare OR sterilization OR

spay OR neuter OR castration OR

ovariohysterectomy OR orchiectomy)))

147

A.2.

Relevance Screening Form

Scoping review: What is the current state of knowledge on approaches to managing companion

animal population dynamics to control the number of owned free-roaming, unowned free-

roaming and unwanted companion animals?

Abstract-level relevance screening form

Question Options Definitions/additional notes

RefID

1. Does the abstract or title

investigate or discuss the

population dynamics or

surveillance or control practices

of free-roaming (owned or

unowned) or unwanted

companion animals?

1) Yes, within the context of

primary research OR

review/commentary.

2) No

Reviewer Decision:

If the reviewer selects option

1) “Yes,” the article will

advance to level 2, where the

full article will be used for

further screening and

appraisal.

If option 2) “No” is selected,

the abstract will be

EXCLUDED.

IMPORTANT: Please use

your best judgement in

deciding whether an abstract

is relevant or not; however, if

you are quite unsure we would

prefer you pass it through as

"yes".

Companion animals are defined

as any animal species kept for

companionship and enjoyment

or a household animal, as

opposed to livestock, laboratory

animals, working animals or

sport animals, which are kept for

economic reasons.

Population Dynamics refers to

any process that affects the size

and or structure of a companion

animal population over time

(e.g. births, deaths, migration).

Surveillance to monitor the

population size.

Control refers to decreasing or

maintaining.

Control Practices examples:

Trap neuter release (TNR)

148

Low cost or early spay and

neuter

Euthanasia

Free-roaming companion

animals are defined as

companion animals that are

living outdoors at least part of

the time, not confined to an

owner’s residence or property at

that time and not under direct

supervision.1,2

Straying is used to describe

companion animals that have a

home and are free-roaming, not

confined to an owner’s

residence or property at that

time and not under direct

supervision.1,2

Owned free-roaming

companion animals are defined

as owned companion animals

that are straying from the

owner’s residence or property.1

Abandoned is used to describe

companion animals that are

discarded or left to fend for

themselves rather than being

formally surrendered to a

facility by their previous owner.6

Feral is used to describe

companion animals that are free-

149

roaming and unsocialized to

humans.2

Unowned free-roaming

companion animals are defined

as unowned companion animals

that are abandoned, or feral. 2, 3, 4

Surrender is defined as when

the owner of a companion

animal which is no longer

wanted takes the animal to an

animal shelter or municipal

pound and legally surrenders all

further claim to ownership of the

companion animal.6

Unwanted companion animals

are defined as companion

animals who are not free-

roaming but are being

surrendered to a shelter, are

being given away, are being

sold, killed, or euthanized by

their owners.5

Stray is used to describe

companion animals that are

socialized unowned and free-

roaming, or feral.2

Primary research is defined as

any original research using

specific quantitative, qualitative

or both methods to investigate

the issue of companion-animal

population dynamics to control

the number of owned free-

150

roaming, unowned free-roaming

and unwanted companion

animals and report new results.6

Review/commentary is defined

as a comprehensive or brief

narrative review or commentary

(from peer-reviewed articles to

lay magazine or newspaper

articles or briefs) describing

and/or discussing the issue of

companion-animal population

dynamics to control the number

of owned free-roaming,

unowned free-roaming and

unwanted companion animals,

with or without mentioning any

case study or contextual

examples. No methods

(qualitative or quantitative) are

reported.6

1Slater, et al., 2008

2Slater, 2004

3Faulkner, 1975

4Feldman & Carding, 1973

5Fielding, 2010

6Coe et al., 2015

References

Coe, J. B., Young, I., Lambert, K., Dysart, L., Nogueira Borden, L., Rajić, A. (2014). A scoping

review of published research on the relinquishment of companion animals. Journal of Applied

Animal Welfare Science, 17, 253-273.

Faulkner, L.C. (1975) Dimensions of the pet population problem. Journal of the American

Veterinary Medical Association, 166, 5, 477-478.

Feldmann, B. M., & Carding, T. H. (1973). Free roaming urban pets. Health Services Report,

88(10), 956-962.

151

Fielding, W.J. (2010). Dog breeding in New Providence, the Bahamas, and its potential impact

on the roaming dog population II: The fate of puppies. Journal of Applied Animal Welfare

Science, 13, 4, 300-313.

Slater, M.R., Di Nardo, A., Pediconi, O., Dalla Villa, P., Candeloro, L., Alessandrini, B., & Del

Papa, S. (2008). Free-roaming dogs and cats in central Italy: Public perceptions of the problem.

Preventive Veterinary Medicine, 84, 27-47.

Slater, M.R. (2004). Understanding issues and solutions for unowned, free-roaming cat

populations. Journal of the American Veterinary Medical Association, 225, 9, 1350-1354

152

A.3.

Data Characterization and Extraction Form

Question Options Definitions/Additional Notes

1. Is this a review,

commentary or primary

research article on the

issue of free roaming

(owned or unowned) or

unwanted companion

animal population

dynamics, control

practices or surveillance?

o Yes, review or

commentary

o Yes, qualitative primary

research

o Yes, quantitative primary

research

o Yes, mixed-methods

research

o None of the above,

specify reason for

exclusion:

- Not Relevant:

- Other:

o Other (1 sentence to 1

paragraph on the topic but

not main focus of the

article)

If “None of the above” is

selected, article will be

Excluded. Please specify the

reason for exclusion and

submit the form without

completing the remaining

questions.

Companion animals are

defined as any animal species

kept for companionship and

enjoyment or a household

animal, as opposed to

livestock, laboratory animals,

working animals or sport

animals, which are kept for

economic reasons.

Owned free-roaming

companion animals are

defined as owned companion

animals that are straying from

the owner’s residence or

property.1

Unowned free-roaming

companion animals are

defined as unowned

companion animals that are

abandoned, or feral. 2, 3, 4

Unwanted companion

animals are defined as

companion animals who are

not free-roaming but are

being surrendered to a shelter,

are being given away, are

being sold, killed, or

euthanized by their owners.5

Population Dynamics refers

to any process that affects the

size and or structure of a

companion animal population

over time (e.g. births, deaths,

migration).

Surveillance to monitor the

population size.

153

Control Practices examples:

Trap neuter release (TNR)

Low cost or early spay and

neuter

Euthanasia

Re-homing

Review or commentary: A

comprehensive or brief

narrative review or

commentary (from peer-

reviewed articles to lay

magazine or newspaper

articles or briefs) describing

and/or discussing the issue of

pet abandonment, with or

without mentioning any case

study or contextual examples.

No methods (qualitative or

quantitative) are reported.

Primary research: Any

original research using

specific quantitative,

qualitative or both methods to

investigate the issue of

unowned or owned free-

roaming or unwanted

companion animals and

report new results.

Qualitative research: Aimed

at understanding social

phenomena, exploring issues,

and answering questions of

“why” and “how”. Examples:

focus groups, interviews.

Quantitative primary

research: Investigator(s)

collected samples or data

themselves for analysis (e.g.,

cross-sectional studies,

surveys, case-control studies)

154

Mixed-method research:

Conduct of qualitative and

quantitative methods in the

same study (e.g., focus

groups and a quantitative

survey/questionnaire)

2. Is the article in English or

Spanish?

o English

o Spanish

o Other: please specify

If “Other” is selected, article

will be Excluded.

3. Author Name(s)

4. What year was the article

published?

5. What is the type of

document?

o Journal Article

o Lay Magazine Article

o Conference Proceeding

o Newspaper Article

o Government or Research

Report

o Thesis or Dissertation

o Book or Book Chapter

o Other, Please Specify

6. Where was the study

conducted? (Country,

State/Province, City – if

given)

o

o Not Reported

Global: One or more

countries on at least 3

continents.

7. Source of Funding o Government

o Industry

o Public Health Agency

o University

o Other: Please Specify

o Not Reported

8. What is the main study

(review) objective as

stated by the authors?

o

o Not Reported

9. What is the study design? o Observational Study

a) Cross Sectional

b) Cohort

-Retrospective

-Prospective

c) Case-Control

-Retrospective

-Prospective

d) Prevalence Survey

Observational study:

Assignment of subjects into a

treated group versus a control

group is outside the control of

the investigator.

Cross-sectional: Observation

of all of a population, or a

representative subset, at a

defined time

155

e) Case or Case

Series

o Experimental Study

a) Controlled Trial

b) Challenge Trial

c) Quasi Experiment

d) Other, please

specify

o Qualitative Study

a) Grounded Theory

b) Ethnography

c) Phenomenology

d) Not Specified

e) Other, please

specify

o Routine monitoring or

surveillance data

collection

o Mathematical modeling

or methodology study

o Other, please specify

o Not applicable, this is not

primary research

Cohort study: A study in

which individuals with

differing exposures to a

suspected factor are observed

over a period of time for

occurrence of an outcome

Case-control study:

Compares exposure in

patients who have a condition

(the 'cases') with subjects who

do not have the condition, but

are otherwise similar (the

'controls').

Prevalence survey:

Measurement of outcomes in

a defined period of time

but doesn’t measure or

investigate potential

predictors

Case Report or Case-series: A descriptive study of a

single individual (case report)

or small group (case series).

Experimental study: Each

subject is randomly assigned

to a treated group or a control

group before the start of the

treatment

Control trial: An

experimental study in which

people are allocated to

interventions and evaluated

for outcomes. For this

question, RCTs are included.

Challenge trial: An

experiment where subjects are

artificially challenged or

exposed to the disease agent

156

Quasi-experiment: An

experiment in which subjects

are not randomly assigned to

groups (e.g., before-after

comparison)

Qualitative study: Aimed at

understanding social

phenomena, exploring issues,

and answering questions of

“why” and “how”.

NOTE: For qualitative

studies please select the

design/methodology that is

identified by the author, and if

none is identified explicitly,

choose “not specified”

Grounded theory:

Development of a theory that

is grounded in data collected

from the field. Often uses

interviews.

Ethnography: Description

and interpretation of a cultural

or social group. Often uses

interviews, in-depth field

work and observations.

Phenomenology:

Understanding the essence

and meaning of experiences

of a phenomenon. Often uses

long, in-depth interviews.

Not specified: Qualitative

study that is not described as

one of the above

methodologies or another

methodology (e.g., case

study).

Routine monitoring or

surveillance data collection: Primarily cover articles that

157

report on an ongoing and

systematic data collection, or

the analysis and interpretation

of data related to our study

question.

10. What are the companion

animal population

studied?

Please Specify ALL that

Apply

o Dogs

o Cats

o Rabbits

o Other, please specify

o Not Specified

Companion animals are

defined as any animal species

kept for companionship and

enjoyment or a household

animal, as opposed to

livestock, laboratory animals,

working animals or sport

animals, which are kept for

economic reasons.

11. What types of populations

were studied?

Please Specify ALL that

Apply

o Owned free roaming

o Un-owned free roaming

o Unwanted

o Owned uncertain

o Not Reported

Owned free-roaming

companion animals are

defined as owned companion

animals that are straying from

the owner’s residence or

property.1

Unowned free-roaming

companion animals are

defined as unowned

companion animals that are

abandoned, or feral. 2, 3, 4

Unwanted companion

animals are defined as

companion animals who are

not free-roaming but are

being surrendered to a shelter,

are being given away, are

being sold, owners.5

Owned uncertain refers to

companion animals who are

owned but it cannot be

determined if they are free

roaming or solely kept

indoors.

12. What was the research

focus area/theme of

investigation?

Please Specify ALL that

Apply

o Population Dynamics:

o Surveillance

Population Dynamics refers

to any process that affects the

size and or structure of a

companion animal population

158

o Control practices (if yes

go to question 13, if no

skip to question 14 )

o Opinions/Perceptions

o Other, please specify

over time (e.g., births, deaths,

migration).

Surveillance to monitor the

population size.

Control Practices examples:

Trap neuter release (TNR)

Low cost or early spay and

neuter

Euthanasia

Re-homing

13. What type of control

practices were

investigated (or discussed

for review articles)?

Please Check ALL that Apply

o Spay and Neuter

a) Early Spay and Neuter

b) Traditional Spay and

Neuter

c) Low cost or

subsidized Spay and

Neuter

d) Non-Surgical Spay

and Neuter

-Chemical Castration

- GnRH

immunocontraceptive

(GonaConTM)

-Zona pellucida

glycoproteins

immunocontraceptive

-Hormonal Implants

-Other, please specify

-Not specified

e) Trap Neuter Release

f) Trap Neuter Relocate

g) Trap Vasectomy

Hysterectomy Release

h) Trap Vasectomy

Hysterectomy

Relocate

i) Trap

Ovariohysterectomy

Release

j) Trap

Ovariohysterectomy

Relocate

Spay and Neuter refers to

sterilization

Traditionally done via

surgical methods:

a) Spay removal of

ovaries, uterus or both

b) Neuter removal of

testes

Early spay or Early neuter

refers to being spayed or

neutered before the cat or dog

has reached the age of 24

weeks

Non-Surgical Spay and

Neuter refers to treatments

that permanently or

temporally inhibit fertility

Alternative Terms

Spay and Neuter =

Sterilization, sterilized, fix,

fixed, de-sexed, de-sex

castration, gonadectomy,

orchiesctomy,

ovariohysterectomy,

hysterectomy, ovariectomy,

altered, castrate, castrated

Early Spay and Neuter =

prepubertal, paediatric, young

or juvenile spay and neuter

159

k) Shelter Neuter

Release

l) Return-to-Field

m) Other, please specify

n) Not specified

o Euthanasia

a) Poison

b) Intravenous injection

c) Shooting

d) Gas

e) Blunt force trauma

f) Other, please specify

g) Not specified

o Legislations/Regulations

a) Licensing or

Registration

b) Limit the number of

free roaming cats

c) Mandatory Spay and

Neuter

d) Breeding laws

e) Other, please specify

f) Not specified

o Re-homing

o Education

o Vaccination

o Other, please specify

o Not Reported

Trap Neuter Release = Trap

Neuter Return, TNR, catch

neuter release/return

Trap Vasectomy

Hysterectomy Release = Trap

Vasectomy Hysterectomy

Return or TVHR

Trap Ovariohysterectomy

Release = Trap

Ovariohsterectomy Return

Euthanasia = eradication or

culling

Re-homing = adopting

14. Who are the stakeholders

(as specified by the

authors)?

Please Check ALL that Apply

o Veterinarians

o Shelters

o Rescues

o Animal Welfare

Professionals

o Public Health

o Ecologists

o Society/General Public

o Corporations and

Institutions

o Small Businesses

o Pounds

o Animal Control Facilities

o Other, please specify

o Not Reported

Shelters include SPCAs, and

humane societies

Rescues generally on take in

animals of a specific species

but sometimes they focus on

a specific breed or type

Pounds are government run

facilities that take in strays or

surrendered animals

Animals Control are also

government run facilities

where animals can be

surrendered and strays can

brought in. However animal

control facilities can deal

160

with cases of animal abuse or

animal attacks.

15. What were the main

outcomes investigated or

discussed?

Please Check ALL that Apply

o Free-roaming/unwanted

companion animal

population size

o Number of euthanized

free roaming/unwanted

companion animals

o Number of free

roaming/unwanted

companion animals in

shelters

o Number of adoptions

from shelters

o Number of shelter intakes

o Prevalence of disease in

free roaming/unwanted

companion animals

o Cost Benefit (economics)

of a control program for

free roaming/unwanted

companion animals

o Improve methodology of

control practices

o Views/opinions on free

roaming/unwanted

companion animals

o By-laws and legislations

o Non-zoonotic diseases,

specify disease:

a) Feline Leukemia

Virus (FeLV)

b) Canine Distemper

c) Canine Papilloma

Virus (CPV)

d) Feline Papilloma

Virus (FPV)

e) Other, please

specify

o Zoonotic Disease, specify

disease:

a) Rabies

b) Toxoplasma

gondii

Zoonotic diseases refers to

diseases that can spread

among species (specifically

transmission from animals to

humans)

Ectoparasite refers to

parasites that live outside

their host

Alternative Terms

Adoptions = rehoming

161

c) Leishmaniasis

d) Bartonella

e) Brucellosis

f) Other, please

specify

o Ectoparasites (e.g. Fleas,

ticks, mites)

o Other public health/safety

issues (e.g. Animal bites,

sanitation)

o Protect the environment

and other species

a) Birds

b) Reptiles

c) Other mammals,

please specify

d) Biodiversity

e) Other, please

specify

o Other, please specify

16. Was the effectiveness of

control practices

investigated or discussed?

- Yes, for each practice

investigated for

effectiveness, please

specify the following

- For Primary Research

a) Control Practice

b) Population

c) Outcome(s)

d) Effectiveness

(effective or no

effective)

e) Significant, non-

significant, or not

assessed for

statistical

significance

- For Reviews/

Commentaries

a) Control Practice

b) Population

c) Outcome(s)

d) Effectiveness

(effective or no

effective)

e) Significant, non-

significant, or not

162

assessed for

statistical

significance

o Not reported

17. Are raw/unadjusted data

or measures of

association/effect

provided?

Please Check ALL that

Apply

o Yes

a) Prevalence outcome

b) Dichotomous outcome

(2X2 table data)

c) Continuous outcome

d) Measure of

association (OR, RR)

e) Modelling

coefficients/beta

parameters

f) P values

g) Measure of variability

(CI, SE, SD)

h) Spatial analysis

i) Ordinal/Likert scale

j) Other:

o No

a) Graphical

b) Other reason:

o N/A – qualitative study or

review/commentary

Yes, please specify:

Raw results or

measures of

association/effect

unadjusted by

statistical modeling

are provided

Minimum necessary data:

a. Prevalence/frequency:

Following data must

be reported measuring

in at least ONE

microbe in ONE

discrete sample type:

Numerator and

denominator, or

Proportion + EITHER

numerator or

denominator

b. Continuous outcome

Must be provided

with a measure of

variability AND

sample size

c. Measures of

association/effect:

OR/RR/IR/RD/PAF/

AFe reported and its

measure of variability

(SE, SD, CI) or P-value

and sample size (n) is

reported

Spatial analysis or spatial

statistics includes any of the

formal techniques which

study entities using their

topological, geometric, or

geographic properties.

An ordinal measure involves

an ordered series, such as

graded responses to an item

163

on a questionnaire: Response

choices: Strongly agree = 4,

Agree = 3, Neither agree nor

disagree = 2, Disagree = 1,

Strongly disagree = 0.

Likert scale - an item is

presented as a declarative

statement, followed by

response options that indicate

varying degrees of agreement

with or endorsement of the

statement

18. For primary research

studies, what data

collection methods were

used?

o Quantitative questionnaire

or survey, specify details:

o Qualitative interviews,

specify details:

o Observations, specify

details:

o Focus groups, specify

details:

o Analysis of documents,

specify details

o Other, please specify

o Not specified

o N/A – not primary

research

19. Who collected the data? Please check ALL that

apply

o Research

authors/technicians

o Veterinarians

o Shelters

o Public Health

o Ecologists

o Society/General public

o Other, please specify

o Not Reported

o N/A

20. For qualitative research

studies, what were the

main themes

investigated/identified?

o

o Not Applicable

21. Do the authors explicitly

report the strengths of

o Yes, please specify

o No

164

their/this research in

general?

o Not applicable, not

primary research

22. Do the authors explicitly

report the weakness of

their/this research in

general?

o Yes, please specify

o No

o Not applicable, not

primary research

23. What are the overall

recommendations of the

authors?

Please Check ALL that Apply

o Control the number free

roaming/unwanted

companion animals

o Increase Spays and

Neuters

a) Early Spay and Neuter

b) Traditional Spay and

Neuter

c) Low cost or

subsidized Spay and

Neuter

d) Non-Surgical Spay

and Neuter

-Chemical Castration

- GnRH

immunocontraceptive

(GonaConTM)

-Zona pellucida

glycoproteins

immunocontraceptive

-Hormonal Implants

-Other, please specify

-Not specified

e) Trap Neuter Release

f) Trap Neuter Relocate

g) Trap Vasectomy

Hysterectomy Release

h) Trap Vasectomy

Hysterectomy

Relocate

i) Trap

Ovariohysterectomy

Release

j) Trap

Ovariohysterectomy

Relocate

k) Shelter Neuter

Release

l) Return-to-Field

165

m) Other, please specify

n) Not specified

o Increase Euthanasia

a) Poison

b) Intravenous injection

c) Shooting

d) Blunt force trauma

e) Other, please specify

f) Not specified

o Decrease Euthanasia

a) Poison

b) Intravenous injection

c) Shooting

d) Blunt force trauma

e) Other, please specify

f) Not specified

o Enforce new and or

existing

Legislations/Regulations

a) Licensing or

Registration

b) Limit the number of

free roaming

companion animals

c) Mandatory Spay and

Neuter

d) Breeding Laws

e) Other, please specify

f) Not specified

o Increase the number of

free-roaming/unwanted

companion animals re-

homed

o Increase Public Education

o Increase Vaccination

o Control the spread of

disease

o Other, please specify

o None

o Not Specified 1Slater, et al., 2008

2Slater, 2004

3Faulkner, 1975

166

4Feldman & Carding, 1973

5Fielding, 2010

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M. Kržanović 2010 Bosnian

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A. Giacometti, O. Cirioni, M.

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B. Kalz, K. M. Scheibe, I.

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A. M. Gerbers, V. H.

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M. Röken 2002 Swedish

F. X. Soesilo 1990 Indonesian

S. Posière 2005 French

F. Dieffenbacher 2006 German

T. Alogninouwa, B. Kamara,

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J. B. Neto 2000 Portuguese

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B. D. Canatto, E. A. Silva, F.

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A. W. C. da Silvia 2014 Portuguese

F. R. M. Soto, H. J.

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Anonymous 2001 German

Anonymous 2010 Thai

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J. Müller 1964 Danish

Anonymous 2012 Portuguese

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A.6.

Description of Articles Unable to Obtained Excluded from the Study

Authors Year

H. Matter, R. Fico, & B. E.

Neuenschwander

1998

Z. K. Afridi, I. Ahmad, Q.

Habibullah, & S. Efroz

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Universities Federation for

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W. W. Henderson 1940

P. Maheshwari 2012

J. Castro, J. Molina, P.

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H. H. Brassey-Edwards 1934

J. Okeww-Acai, R. Omara, J.

S. Onyait, et al.

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D. A. Georgieva, A. I.

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Anonymous 2014

J. E. R. Roe 1958

A. Cecchini 1933

Anonymous 1988

D. E. Faulkner 1954

D. Otranto & C. Cantacessi 2007

B. J. Coman 1992

Anonymous 1974

A. O. Miranda, G. Marder, &

A. M. Hojder.

1998

D. J. Evans 1999