Proper Dry-Off Procedures to Prevent New Infections

and Cure Existing Cases of Mastitis

Stephen C. NickersonUniversity of Georgia

scn@uga.edu

Presentation Outline• Intramammary infection process

• Anatomy & physiology of dry period

• Methods of drying off

• Antibiotic therapy

• Teat sealant treatment

• Role of Vaccination

• Other management factors

Result:

Decreased milk quality & yield

Adversely affects animal health

Mastitis Definition:

IMIMastitis (intramammary infection)

occurs when bacteria enter the

teat orifice, multiply within the

mammary gland, and elicit an

inflammatory response (↑SCC).

An understanding of:

Physiology of the dry period

Anatomy of teat end tissues

Instrumental in maximizing benefits of

properly drying off mammary quarters

to cure IMI and prevent new infections

Clinical/Subclinical

Mastitis

Physiology of the Dry Period

• Function of the mammary gland during

lactation: continuous synthesis/secretion

of large quantities of milk; then dried off.

• The mammary gland progresses through three distinct stages:– 1) Active involution

– 2) Steady state involution

– 3) Colostrum formation

• “Colostrogenesis”

After

dry-off

Dry Period:

Needed to optimize milk

production in next lactation

(↑ Susceptibility to mastitis)

1 2 3Active Steady

state

6-fold higher

(2-3 weeks)

(305 d)(60 d)

Majority: Environmentals:

• Escherichia coli

• Streptococcus uberis

(In addition to

existing IMI)

>50% of all CM

in early lactation:

“Environmentals”

acquired during

the dry period

---Lactation---

Colostro-

genesis

Why the increased susceptibility at the beginning and end of the dry period?

1. Active Involution(Termination of milking→3-4 weeks into dry period)

• Maximum accumulation of fluid occurs

within ~2 to 3 days of drying off.

• Milk volume decreases significantly by

~4 days of involution.

• Fluid volume continues to decrease

through at least day 16 of the dry

period, and probably through day 30.

Milk

Result of: Resorption, some leakage

1. Active Involution(Increased antimicrobial activity)

• ↑Lacto-ferrin (LF):

– Binds to iron (Fe++) in mammary secretions

– Making it unavailable to bacteria that require

it for normal growth, like coliforms (E. coli)

– Plays a role in control of leukocyte activity

• Phagocytosis/killing

• ↑Antibodies

– IgG1, IgG2, IgA, IgM

• Enhance leukocyte function/neutralize bacteria

Neutrophil

Bacteria

LF

Fe

Fe

Fe Fe

FeFe

Fe Fe

Need Fe

for growth

Bacteria

But still, new infections occur…

Elevated rate of new infections

during active involution due to:

Flushing of colonized bacteria terminated

- No more 2-3 times a day milking

Udder sanit. & teat dipping discontinued

- Bacteria accumulate on the skin

Leukocytes more active in removing milk

components than microorganisms

Dilation and shortening of teat duct

- Milk pressure, leakage, ↓ keratin

Casein & fat: Inefficient

2. Steady State Involution(1-2 weeks)

• 1. High levels of antibacterial factors:

Antibodies & Lactoferrin (sequesters Fe)

• 2. Reduced rate of bacterial penetration

through the teat canal

– Lower level of teat end exposure

to potential mastitis pathogens

• The development of a keratin plug

(Functions as a physical & chemical

barrier: antimicrobial proteins & fats)

↓ Susceptibility to new infections due to:

• Susceptibility to new infection is

increased just prior to calving:– Increased fluid volume → dilation of the

teat canal (leaking) allowing bacterial entry

– Reduced leukocyte numbers and loss of

their ability to engulf microorganisms.

– Utilization of milk components by mastitis microorganisms → growth & multiplication.

– Absence of residual antimicrobial activity of dry cow therapy.

• Lack of antibiotic residues from treatment

of all four quarters at the time of drying off

3. Colostrogenesis(1-3 weeks prepartum)

Teat canal

Teat canal (duct) is the 1st line of defense, providing:

(A) Keratin and (B) Sphincter muscle

as physical/chemical barriers

Maintains tight

closure

• Physical plug

• Antibacterial

-Proteins

-Fatty acids

Keratin

Teat cistern

Role of mammary gland anatomy

in preventing new mastitis cases

When treatments are

applied to the teat end,

the natural tissue

architecture (keratin,

sphincter) should be

protected as much as

possible to maximize

treatment efficacy, e.g.,

Antibiotic or Teat seal

Protection of teat end tissues at

time of drying off: IMPORTANT

Full Insertion:Stretches sphincter

Dilates teat canal

Removes keratin

Introduces bacteria

Partial Insertion:Maintains integrity

Minimizes bacterial

entry into the gland

Environ.

bacteria

E. coli

Prototheca

Nocardia

T. pyogenes

Yeast

Partial

insertion

(2-3 mm)

Full

insertion

Bacteria

**Sanitize teat orifice, use partial insertion technique, dip teats

Using

gloves

Proper infusion procedures:

(Antibiotic or Teat sealant)

Kills contaminating bacteria

• Reduce feed over last 2 weeks to reduce yield

– Feed high fiber diet; eliminate grain; switch from

alfalfa to grass, or straw for very high producers.

– Reducing water intake is questionable as it is the

most crucial nutrient and promotes animal health.

• Dry-off at a BCS of ~3.5

• Abrupt cessation or intermittent milking

– Intermittent alleviates back pressure on milk-

producing cells; prolongs milk production.

• After dry-off switch to balanced gestation diet

• Provide adequate ventilation in housing

– ↓ moisture (reduces bacterial growth; ↓mastitis)

Management factors to consider at dry-off to

minimize stress and environmental exposure

*

Abrupt cessation vs. Intermittent milking

• Milk for ~291-298 days

– 1-2 weeks prior to dry-off date

• For last 1-2 weeks of lactation:

– Eliminate conc. (hay only)

– Limit water intake????

– Milk intermittently, e.g., 1X

• Infuse/place in far-off lot

Method of Drying Off

Accelerates involution

↓ New IMI at calving

(↓ production 22-47%)

• Milk for 305-day lactation

• Milking

• Infuse with DCT +/or TS

• Place in far-off pasture/lot

IMI rate based on method of dry-off and milk yield at dry-off

0

10

20

30

40

50

IMI Rate Reduced (%)

32

50

Intermittent milking*

Intermittent + Ration Change*

_________________Oliver et al., 1990

*All quarters received DCT*IMI defined as a change in LS from<4.0 at dry-off to >4.0 at first test

___________________Dingwell et al., 2001

“Leaking”

Reductionin new IMI

vs. abrupt

Cows with greater milk yield at

dry-off → leak milk→ incomplete

keratin plug formation at teat end

Increases chances for bacterial

entry through the teat canal

Within several days-weeks,

teat canal closes up, with the

formation of a keratin plug

Decreases bacterial penetration:

Physical barrier, antimicrobials

Keratin plug

50% of cows had open teat ends

(leaky) 1 week after dry-off

23% of cows had open teat ends

(leaky) 6 weeks after dry-off

47% of cows producing more than

46 lbs at dry-off had open teat ends

6 weeks after dry-off

______________

Dingwell, 2003

Research studies….

Greater risk of infection!Leaky cows: 4X more likely to develop

clinical mastitis during the dry period

caused by envir. streps and coliforms

Mammary quarter infection status at dry-off:

1. 1.

2.

2.

Infected Infected

Uninfected

Uninfected

1. Existing intramammary infections that should be treated & eliminated

2. Uninfected quarters that should? be treated to prevent new infections

a) Antibiotic? b) Teat seal? c) Teat seal + antibiotic? d) No treatment?

Treat all 4 quarters

of all cows

Research into the use of

Blanket Dry Cow Therapy:

Treat & Prevent

Mastitis (No TS)

Treat all 4 quarters of all cows at drying off

“Blanket DCT”(1950s)

Qtr infection Rate Qtr Cure Rate New Qtr IMINo. (%) No. (%) No. (%)

S. aureus 18 (2.78%) 17 (94.4%) 14 (2.16%)

S. agalactiae 23 (3.55%) 23 (100.0%) 11 (1.70%)

S. dysgalactiae 10 (1.54%) 10 (100.0%) 3 (0.46%)

S. uberis 0 0 1 (0.16%)

CNS 137 (21.14%) 107 (78.1%) 80 (12.34%)

E. faecalis 2 (0.31%) 2 (100.0%) 2 (0.31%)

E. coli 1 (0.15%) 1 (100.0%) 0

Other 2 (0.31%) 2 (100.0%) 2 (0.31%)

Total 193 (29.78%) 162 (83.9%) 113 (17.44%)_______________Petzer et al., 2009

Prevalence, cure rates, and new IMI of quarters treated atdrying off with various penicillin & cephalosporin products

Avg: 70-90% 40%↓ (Avg: 50-80%)

DCT: Cures IMI at drying off & prevents new IMI

Multiple antibiotic infusions? Improve cure rates?

• Treating twice at drying off, or

• At dry off & at some later time(s)

• Not demonstrated to be beneficial

• Subsequent treatments after dry-off may pose additional risks:

– Introducing bacteria into the gland via the syringe cannula

– Increasing risk of residues in bulk tank milk after freshening

• Single infusion/qtr. recommended

– Antimicrobial activity persists 2-4 weeks

Selective Dry Cow Therapy (DCT)

External→ Internal→

X• Selecting only the infected or potentially

infected quarters or cows to treat

• To reduce expense, drug use, & development of antibiotic–resistant bacterial strains

• Selection based on culture, SCC (Electronic, CMT)

– Reasonable threshold: 200,000/ml (treat >this level)

• For cows/qtrs assumed uninfected (<200,000/ml):

– Teat sealants may prevent new infections:

Effects of Blanket vs. Selective DCT on

the prevention of new infections

• 729 low SCC cows (<200,000); 16 herds

– 1. Blanket: All 4 qtrs received DCT + Teat seal

– 2. Selective: Only infected cows received DCT + Teat

seal based on + bacterial culture results

• Culture-negative cows received teat seal only

Conclusion: Selectively treating culture+ cows = blanket therapy at dry off

*When SCC at dry-off are <200,000/ml

% Quarters

infected

at calving

_________________

Cameron et al., 2014

Effects of Systemic vs. Intramammary

therapy on Gram+ cure rate after DCT

• 278 cows in 1 herd assigned to 4 tmts:

– 1. DCT + Teat seal (Tomorrow®, Orbeseal®)

– 2. DCT + Teat seal + Tylosin (12 g, IM)

– 3. Teat seal + Tylosin

– 4. Tylosin

Contreras et al., 2012

% Cows cured

ab

ab

a

b

ab P < 0.05)

Use of Internal Teat Sealants at Dry-off

Physical barrier

to Bacteria

• Bismuth/paraffin based

• Infused at drying-off

• + after dry cow therapy

• Removed at 1st milking

Orbeseal™Bismuth subnitrate/mineral oil

Teatseal®

Bismuth subnitrate/paraffin oil

Teat seals: Initial studies - United Kingdom

(Huxley et al., 2002)

• 505 cows with SCC at dry-off of <200,000/ml

• 2 treatment groups:

– 1. Orbeseal (65% bismuth subnitrate in mineral oil)

– 2. Cepravin (250 mg of cephalonium)

• Measured:

– New infections during dry period

– Clinical mastitis in 1st 100 DIM

• Objective: Orbeseal = DCT?

Teat seals: Initial studies - United Kingdom

(Huxley et al., 2002)

*

New infection rate with various mastitis pathogens

*Orbeseal use: 70% fewer E. coli IMI (P<0.01)

Orbeseal = DCT, but better in preventing coliform IMI

25 24

42

15

3521

183

162

Efficacy of Orbeseal™ + DCT

in 437 cows (1748 qtrs)

1. All 4 qtrs infused with DCT

2. 2 contralateral qtrs: Orbeseal

RF

LFLR

RR

Compared with DCT alone, DCT + Orbeseal →

• 30% fewer new infections during dry period

• 33% less likely to develop clinical mastitis

• Lower SCC in early lactation

• Combination superior to DCT alone

________________

Godden et al., 2003

Efficacy of Orbeseal™ + DCT

in 949 cows (multi-herd)

1. 2 qtrs infused with DCT alone

2. 2 contralateral qtrs: DCT + Orbeseal

RF

LFLR

RR

Compared with DCT alone, quarters treated with DCT + Orbeseal:

• 27% less likely to acquire new IMI (all pathogens) during dry period

• 38% less likely to acquire new IMI (environmentals) during dry period

• 58% less likely to acquire new IMI (coliforms) during dry period

________________

Sanford et al., 2006

Combination superior to DCT alone, vs. *environmentals, **coliforms

Summary: Teat sealants + DCT

_____________________

Rabiee & Lean, 2013 (Meta-analysis of 12 trials)

↓new IMI at calving & Clinical mastitis

Addition of DCT lowers SCC (cures IMI)

+ or

Equally

effective

Proper teat seal infusion:

1. Compress area at base

of teat with hand.

2. Insert cannula using the

partial insertion method

3. Slowly infuse contents

so seal remains in teat

1.

2.

If teat cistern is open to gland

cistern, and seal is jetted into

teat, it may be placed high in

the quarter and milk out for

days or weeks after calving.

←Teat cistern

←Gland cistern

• Cooling during warm season (H2O/sprinklers)

– ↑ comfort, DMI, immune function (↓mastitis)

• Daily bedding maintenance/clean pasture

– ↓ pathogen load at teat end (↓mastitis)

• Provide proper nutrition & supplements

– Se, Cu, Zn; Vit. A, D, E; additives (Omnigen)• Improve leukocyte function vs. mastitis pathogens

• Length of the non-lactating or dry period– 1ST lactation cows: 50-60 d; Multiparous cows: 35-45 d

• By milking high-producing cows longer (45- vs. 60-day dry period), yield will be lower when it is time to dry them off

• Vaccination against environmental mastitis…

Other management factors to consider

Vaccination during the dry periodto reduce incidence of coliforms

• Coliform vaccines at dry-off & after calving

– ↓ Clinical mastitis postpartum (2.6% vs. 12.8%)

– Returns $57/cow and profitable when >1% of herd

has clinical coliform mastitis

– 30-40% of all US cows are currently immunized

– Vaccination does not overcome poor environmental

conditions or housing over the dry period

(Gonzalez et al., 1989)

(DeGraves & Fetrow, 1991)

(Hoards Dairyman, 2013)

Coliform vaccination schedule

Endovac bovi

2X , 2-3 weeks

apart

Up to 80% effective in preventing

new cases of clinical coliform IMI

J-VAC

2X, 2-4 wk

later

Envirocore

3X, 7 & 8 mo,

<2 wk calving

Summary• Proper dry-off methods DO promote udder health

• Decrease dietary energy last 1-2 weeks; increase fiber

• Abrupt cessation = Intermittent milking/diet change

– Intermittent: High producers (↓production, ↓leakage at DO)

• Dry period length- Heifers: 50-60 d; Multi: 35-45 d

– Milk high producers longer to decrease yield (↓volume)

• Selective = Blanket for low SCC cows <200,000/ml

– DCT + Teat seal recommended to maximize benefits

– Use Blanket DCT for high SCC cows/herds >200,000/ml

• Use recommended infusion techniques (keratin, sphincter)

• Coliform vaccines: ↑Immunity ↓CM in early lactation

?Questions??The End

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