Successful Mycoplasma eradication

A guide for pig producers and veterinarians

Contents

Introduction 3

Planning 4

Farm suitability 5

Eradication options 6-8

Clean practices 9

Monitoring 10

Summary 11

Acknowledgements 12

Enzootic Pneumonia, the respiratory condition caused by M. hyopneumoniae is one the most prevalent diseases in theswine industry worldwide, affecting pigs of all ages and all typesof farm or production systems.

The economic loses associated with Mycoplasma infections in pigs are not onlyrelated to a decrease in production parameters, such as increases in the numberof days to reach slaughter weight, but are also due to the fact that mycoplasmalpneumonia becomes a chronic condition that predisposes pigs to other bacterialand viral respiratory infections. Mycoplasma are also considered to play acentral role in Porcine Respiratory Disease Complex (PRDC).

Freedom from Mycoplasma hyopneumoniae infection is highly desirable as it canreduce costs, minimise losses and improve productivity performance.

Mycoplasma eradication programmes, when correctly implemented, have beenproven to be highly successful, leading to sustained gains in herd health statusand farm profitability. These gains deliver producers a substantial return oninvestment (ROI) when evaluated against the total costs of implementing theeradication programme.

This ROI analysis considers not just the medication costs but it also takesaccount of the cost of lost (or reduced) production as well as the cost ofincreased labour and the requisite improvements to farm buildings, equipmentand bio-security systems. These related costs substantially exceed the simplecost of treatment. Thus, not only do producers benefit from sustainedproductivity improvement, but they also profit from an upgraded farm facility.

This Mycoplasma eradication guide is a testament to Novartis Animal Health’scontinued commitment to helping swine producers and vets, worldwide, toimprove the health status and profit performance of their herds.

The benefits of Mycoplasma eradication

Is complete eradication a realistic objective?

● What is the pig density in my area?

● Do nearby farms or pig truck routes representa risk to my farm if I eradicate Mycoplasma?

• Epidemiological studies from Europeancountries suggest the airborne transmissionof M. hyopneumoniae occurs between farmslocated within a radius of 2.5-3kms

● Are there any specific seasonal conditions thatrepresent a risk or an advantage if I choose toeradicate?

• Mycoplasma have been observed to survivebetter in cooler, wetter conditions such asare experienced in temperate climatesduring the winter months

Can the eradication programme befunded without placing undue pressureon the business?

● In addition to assessing the impact ofincremental costs (such as extra labour, repairs,cleaning, equipment and medicines) anyfinancial analysis must also make adjustmentsfor the significant reduction in income that willresult from the temporary loss of market pigs

● If total depopulation is proposed a source of‘clean’ pigs must be identified and secured tore-populate the farm

● Finally, the timing of the programme should beplanned to optimize the pig flow and minimizelosses due to lack of market pigs. Seasonal andmarket conditions such as weather conditionsand peaks and troughs in pork prices shouldbe assessed before deciding when to initiatethe programme

Plan carefully before committing to a programme

The first step is to thoroughly assess the financial and logistical impact of starting a Mycoplasmaeradication programme.

It is important to remember that each farm is unique and that the extrapolation the results fromeradication programmes implemented within other herds may not necessarily apply.

Prior to committing to an eradication programme key questions need to be asked, and answeredaffirmatively, to ensure the investment is money well spent.

Is the eradication programme practical?Can it be applied to my pig farm underthe given circumstances?

● A farm-specific program is required which ispractical, reliable and that can be successfullyapplied within the framework of the farmmanagement systems. It is important toremember that each farm is unique and whatcan be applied in one farm may not be validfor the conditions of other swine units

Do not consider an eradication programme unless all the following criteria are met:

● Clinical diagnosis of Mycoplasma is confirmed by demonstration of Mycoplasma hyopneumoniae (usually by PCR)

● The farm is situated a safe distance from the biological threat proffered by neighbouring pigfarms, pig truck routes and other sources of live pigs infected with Mycoplasma

● Adequate funds are secured to cover the full programme costs and the business cash flow requirements

● A comprehensive bio-security and hygiene programme can be established to avoid re-introduction of infection (eg via vehicle traffic, farm visitors or disease vectors)

● The farm buildings including slurry systems, roofing, flooring and ventilation systems are able tobe repaired and returned to good working order

● A supply of Mycoplasma–free replacement stock is available for the future

● All farm personnel are fully committed to the programme

Mycoplasma Eradication Plan Checklist

A plan of attack is needed - the entire farm site and adjacent farm sites should besurveyed before embarking on the eradication program. A farm map should beproduced noting the location of all buildings, roads, boundaries, feed stores, pigdisposal areas and other landmarks such as lagoons, neighbouring roads and nearbyfarm buildings (possibly housing or transporting pigs).

● Record the routes taken by feed trucks andother delivery vehicles and devise new cleanroutes and boundaries

● Weekly task check-lists, with staff and team requirements for each task, need to be compiled

● A detailed list of, and budget for, requiredrepairs, maintenance and replacement workshould be made

● Cost, and availability, of all new equipmentand supplies required to upgrade the farmshould be reviewed

● A large rubbish skip capable of gathering oldand replaced debris from around the farmshould be placed in an area away from thepigs near the farm boundary

● The existing pig disposal unit must be moth-balled and a new, clean one prepared

Ensuring the farm is fit for eradication

Eradication options and pig treatment

1) Total depopulation and restocking

This requires the elimination of all animals fromthe farm followed by thorough cleaning, drying,and disinfection of the entire farm site. Oncedisinfection and a further drying out is completethen the farm is repopulated with animalscertified free of Mycoplasma hyopneumoniae.

This method also provides the opportunity toimprove the genetic stock of the herd and/or to eradicate other pathogens (such as PRRSV and APP) by careful selection of replacementstock with appropriate genetic and pathogen-free status.

Total depopulation eradication programmes do notrequire the use of vaccines and can, in theory, beapplied to virtually any type of pig production unit.

However total depopulation has a major impacton the supply of market pigs. Even if replacementsows are pregnant, there will still be a minimumof 20 weeks without finished pigs for sale.

This economical loss should be fully assessed,along with the cost of buying in replacementstock, before committing to the programme.

BoarShed FarrowingHouse Dry

Sow

Boar

Shed

Farrowing

HouseDrySow

BoarShed

FarrowingHouse

DrySow

Boar

Shed

Farrowing

House

DrySow

Dead PigChiller

Workshop

Laneway

Effluent Ponds

Car Park

CLEAN AREA DIRTY AREA

Office

Water

Ramp

Gas

AI Storage

EmergencyEvacuation Point

MedicationStorage

2) Partial depopulation and medical eradication

Pig producers often choose a partialdepopulation method because it is less financiallypunitive. Partial depopulation significantlyreduces the loss of market pigs for sale, removesthe cost of restocking altogether and conservesthe genetic profile of the herd. This methodrequires the depopulation of weaners, growersand finisher premises.

Mycoplasma shedding has never been shown to occur beyond 36 weeks after a pig becomesinfected. Therefore the most reliable results areachieved when all pigs under 10 months of ageare removed from the farm. All remaining pigsmust then receive a suitable treatmentprogramme to rid them of any lingeringMycoplasma hyopneumoniae.

Extensive experience shows that Denagard is thedrug of choice which, coupled with cleaning anddisinfection, can eradicate Mycoplasma in morethan 90% of farms at the first attempt.

Pre-planning

There must be a 15 day gap in mating some 100 days before week 1 of the programme. This isdesigned to achieve a corresponding cessation of farrowing during weeks 4-6 of the eradicationprogramme. This is the period when the depopulated area is being cleaned and the pigs transferred.

Weeks 1-4: Preparation

● Remove all pigs up to 100kg from the farm leaving only adult pigsover 10 months of age

● Empty, clean and disinfect weaner, grower and finisher facilities

● Carefully select and cull pigs to enhance the future farm breeding programme

● Cull or remove all pigs with any sign of respiratory or other disease

● Do not introduce new animals

Weeks 4-8: Transfer

● Denagard medication of breeding animals, lactating sows, suckling piglets according to Novartisprogramme. Cull all pigs that refuse to eat their fully medicated diet

● Do not introduce new animals. Stop all farrowing and subsequent pig flow for a period of 15 days

● During this central period, pigs are housed in a specific ‘dirty’ area of the farm for 2 weeks (weeks 4 to 6), while the remainder of the farm is being intensively cleaned, disinfected andrepaired as required

● At week 6, pigs are declared ‘clean’ and moved to the ‘clean’ area. At this time, pigs are injectedwith Denagard, and thoroughly washed and disinfected in a deep bath.

● The area previously used for the ‘dirty’ pigs can be now cleaned, disinfected and repaired (as required)

Weeks 8-12: Production normalisation

● The whole farm site now clean, populated, and working. New litters may be born now and processed

● Pigs remain on Denagard treatment for a further 4 weeks as insurance against any re-infection

● After the 12th week, Denagard treatment may be removed and new Mycoplasma-free pigs can beintroduced onto the farm

Model for partial depopulation and treatment eradication

3) Modified partial depopulation

For some large multi-site farms a modified partial depopulation method has beensuccessfully deployed.

This programme combines the design of thepartial depopulation method with someadditional disease eradication strategies such asherd closure, stabilization of the sow herdimmunological status, and off-site early weaning.

Breeder units

Overstock your sow inventory. Ensure 100%seroconversion of the entire breeding herd. Keeponly animals older than 10 months of age.

All pregnant and lactating breeder pigs should befed Denagard-medicated diets at high doses priorto, and during, the commencement of earlyweaning transfer programme.

Early weaning transfer

A large group of pigs are weaned at the earliestage possible, and moved onto the separate, andclean weaner-nursery sites. This must be done onan all-in, all-out basis. All piglets should beinjected with Denagard at the time of transfer.

Biosecure all-in, all-out practices

The new clean pigs at the weaner sites, and attheir subsequent grower-finisher sites, must bekept in strict bio-secure, separate and isolated all-in, all-out sites to ensure that re-infections withMycoplasma do not occur.

This modified approach offers the mostadvantages from the pig production flow point ofview. However, as there is a lack of depopulationin grower and finishing sites, the risk ofMycoplasma re-infection is greater.

What is the best Denagard dose foryour farm?

The principle of eradication is the removal of100% of Mycoplasma hyopneumoniae from 100% of pigs remaining on the farm. Denagarddosage and treatment duration can vary,depending on the farm conditions and results of susceptibility tests.

Example of Denagard standardmedication programme (eradication)

Application Dosage

* thf – tiamulin hydrogen fumarate (Denagard)

Breeding oral 6-8 mg thf */ kg bw, animals 14 days

Half the dose for longer periods (depending on specific farm conditions)

Suckling parenteral 10 mg thf */ kg bw,animals 3 – 4 times during

treatment period ofbreeding animals

Eradication options continued

The epidemiology of Mycoplasma hyopneumoniae is not fully understood. Airborne disease transmission has not been scientifically proved for distancesexceeding 6 metres, neither has vector-borne transmission been proven. However, field observations suggest that both these routes, especially airborne transmission, are possible up to a distance of 3 km.

Mycoplasma hyopneumoniae is generally considered a ‘pig-associated’ bacterium, which only lives a shorttime outside the host pig, and requires certain climatic conditions (fresh and humid weather) in order toremain viable. So cleaning of the farm should be thorough but not necessarily exhaustive. This minimumlevel of cleaning is usually not sufficient to eradicate swine dysentery or ileitis at the same time.

Correct cleaning consists of:

● washing all surfaces with soapy detergent andwater to ensure the removal of all organic matter

● drying the washed surfaces completely

● applying a disinfectant capable of killingMycoplasma (eg quarternary ammonia)

When cleaning and disinfecting, the hotter and drierthe weather, the better as this will assist drying.Shed panels may be removed to aid drying.

The role of vectors in the transmission of M. hyopneumoniae has not been evaluated. However,any mechanical vector should be considered as arisk for uninfected farms. To this end, expertassistance should be sought to make sure allrodents and birds are killed.

In the central phase of the eradication program(around week 6 of the 12 week program) pigdisposal should be switched to the new ‘clean’ site.At this time, the new ‘clean’ staff and equipmentshould take over in the ‘clean’ area of the farm nowholding the clean pigs. They should not have contactwith the remaining ‘dirty’ staff and farm areas.

Clean, disinfect, and adopt new ‘clean’ practices

● Remove all bedding materials, such asstraw, during the eradication

● Remove garbage from inside and outsidethe premises

● Empty, clean, disinfect and dry holdingtanks and slurry canals

● Shift, clean and disinfect slats, slurrygates and other heavy parts of the slurry system

● Wash all surfaces, inside and outside thepig sheds, with soapy detergent toensure removal of all organic matter

● Clean and disinfect tools, footwear andother ‘vehicles’

● Dry the washed surfaces completely

● Disinfect the farm site (includingvehicles and equipment) withappropriate disinfectant

Although Mycoplasma transmission byrodents, flies, birds, or any vectors has notbeen established, it would be wise to adoptpest control programmes to enhance thebio-security status of the site. This isespecially important for the eradication ofother pathogens as well as improving theoverall herd health status.

Cleaning and disinfection checklist:

Because there is a lack of reliable diagnostic tools for the identification of Mycoplasmahyopneumoniae, clean status is usually monitoredat the slaughterhouse by examination of lungs forMycoplasma lesions.

The introduction of a small group of naive pigsand their subsequent evaluation is anothereffective means to monitor the herd for ongoingfreedom from infection.

Additionally there are effective vaccines forMycoplasma which can help to protect the herdfrom subsequent disease, but it is important toremain vigilant for emerging clinical signs soappropriate treatments can be rapidly deployed.

Monitor success and remain vigilant to disease threats

After the cessation of treatment (after the full 12 weeks) evaluate growth rates andthe financial return on investment by comparing the productivity parameters,veterinary costs and mortality with pre-eradication data.

To ensure the farm remains free fromMycoplasma hyopneumoniae it is essential to:

● lock gates at the farm entrance with appropriate signage to preventuninvited farm visitors. While manypeople will want to see the ‘new’ farm -don't let them!

● evaluate the growth rates and newfinancial returns on investment bycomparing the productivity parameters,veterinary costs and mortality with pre- eradication data

● rapidly assess any pig with possibleclinical signs of Mycoplasma so effective measures can be taken toprotect the herd

● regularly monitor the herd by checkinglung samples at the slaughter house

● buy only pigs from farms which are freefrom Mycoplasma hyopneumoniae

Maintaining ‘Mycoplasma-free’ status

Summary

Important questions to ask beforeembarking on eradication programmes:

● Is the eradication realistically achievable?

● Is everyone, including every single staffmember, 100% committed to achieving theobjective?

● Is the eradication programme economically viable?

Key benefits of a Mycoplasmaeradication programme:

● Long-term productivity gains due to improvedproduction performance and reduced

● Increased profitability due to reduced medicaland veterinary costs

● Long-term improvement in the overall herdhealth performance. This is due to a reduced risk of PRDC and other disease conditionsencouraged by the presence of Mycoplasmahyopneumoniae

● An upgraded pig production facility with lastingbio-security benefits

Choosing the right eradication approach

Every farm or production site has a unique set ofcircumstances that must be evaluated prior toselecting the best approach and the requiredtreatment protocol. Expert advice is thereforeadvised to ensure all, financial, veterinary and bio-security issues are professionally addressed.

There is a choice of eradication programmes, asoutlined on pages 6-8.

Total depopulation – this involves removing all the animals from the farm site, the cleaning anddisinfecting of the site and the subsequentintroduction of replacement breeding stock known to be free from Mycoplasma hyopneumoniae infection.

Partial depopulation (Swiss Method) – thisinvolves removing some of the animals from thesite, culling poor performing and diseased stock,and confining the remaining pigs to a ‘dirty’ partof the farm site while the rest of the farm iscleaned, disinfected and dried. Pigs undergoDenagard medication.

Modified partial depopulation – this method is a modification of the above Swiss Method thatmaximises pig flow and is more practical for largeproducers. This method does not requiredepopulation of the grower or finisher sites and requires strict all-in, all-out practices.

Ensuring success

Key to the success of the programme is planning,timing and the total commitment of all personnel.Effective planning and timing will ensure theprogramme is effectively deployed minimizing lost production and maximising income.

It is essential that the site infra-structure isupgraded to a level that sustains the programmeand which facilitates the adoption of the bestpossible bio-security practices going forward.

Minimising the threat of re-infection fromneighbouring, introduced or passing stock ismandatory.

Novartis Technical Support

Novartis is 100% committed to supporting pigproducers around the world. For more informationor assistance please view our website atwww.denagard.com for a full list of helpful contacts.

Novartis Animal Health Inc., PO Box CH-4002, Basel, Switzerland.Tel: +41 61 697 57 35 Fax: +41 61 697 67 88www.denagard.com

Acknowledgements

This eradication guide has been reviewed andaccepted by the Denagard Advisory Board and Dr Maria Pieters, the University of Minnesota.

Eradication is not guaranteed, but has beenachieved on many sites around the world whenthese guidelines have been strictly adhered to.

Novartis Animal Health is fully committed to helpingpig producers to enhance the health status, andproductivity, of their herds.