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Fighting TB on another front

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01 December 2010, at 12:00am

RICHARD GARD reports on the latest meeting of the Goat Veterinary Society

THE Goat Veterinary Society meeting at Taunton Racecourse brought together more than 60 veterinary surgeons and goat enthusiasts to share their knowledge and expertise.

Important aspects of disease were presented and discussed, with the chairman, Dr Tony Andrews, keeping the presentations and observations moving along with plenty of opportunities for those important enquiries over coffee and lunch.

The TB policy officer for the Welsh Assembly Government, Daffyd Glyn, outlined the intended programme under the banner, “Leading the fight against TB”. The concern about TB in goats and the earlier outbreak in Wales has led to a testing programme on 40 goat herds with local veterinary surgeons carrying out the tests. Deer are also being sampled post mortem.

Where there is a cattle TB breakdown, the opportunity is taken to test goats, presumably on the same or close contact farms. Currently there is no compensation for goats slaughtered on suspicion of having TB but a consultation is on-going about compensation for camelids, deer and goats.

Eradication plan

An eradication plan for 2011 has been submitted to the Government, adopting a risk-based approach and changes in terminology. A comprehensive programme for reducing the disease in cattle is being developed and full details are available at www.wales.gov.uk/bovinetb. Simon Rolf (veterinary adviser) joined in with the discussion, which raised some challenging aspects.

The impact on goat testing, where herds have been vaccinated against Johne’s disease, was a concern with no definitive solution, although the topic is being looked into. It was agreed that there was “a healthy debate” about the justification for the costs of M. bovis control with consideration of the human health risks.

It would appear that the expenditure to date justifies continuing efforts to control the disease. The occupational health risk to farmers and others in close contact with diseased stock was considered to be low but it was observed that there has not been a detailed assessment.

Vomiting

Members of the society really enjoy a good clinical puzzle and Ed Powell Jackson (Kingfisher Veterinary Practice) detailed an outbreak of vomiting in four goat kids. The smallholding involved borders a housing estate. The goatkeepers live elsewhere and the goats have access to “rough grazing”, including unmown grass, thistles, nettles and brambles with shelters constructed mainly from pallets.

In August 2010 the pygmy goat kids were in good health when seen by the owners the night before but were observed the next day to be salivating profusely, reluctant to move, with sudden projectile vomiting, no diarrhoea or blood in the normal looking droppings, no straining with mild dehydration. The owners and the kids were in distress.

The vomit was foul smelling and brown. Rehydration therapy was administered with relief for abdominal discomfort and in case of inhalation, antibiotics, as well as multivitamins. All drinking water and feed was replaced and the kids were taken back to the house for tender loving care and close observation. The kids made an uneventful recovery with no further vomiting.

In the field there was no evidence of access to poisonous plants or fly tipping. The owners had cleaned troughs with bleach and left them in the sun to dry. Later, deadly nightshade was found that was not evident at the time of the incident. At this time the cause of the incident is unknown and further discussion failed to yield a definitive answer.

Q fever

The details of a Q fever abortion outbreak in an expanding 1,000 diary goat herd was presented by Fin Twomey (VLA Starcross). The goats were permanently housed in large, clean, well-bedded pens. The pens were not washed and disinfected between batches of goats but this may not be a relevant observation.

In February 2007 an abortion outbreak of mainly first parity goats took place 4-6 weeks before the due parturition date. Bacteriology indicated acid fast bacilli from placentas, with PCR confirming Coxiella burnetti. Advice was given to dispose of any infected materials and bedding.

Prophylactic antibiotics for other pregnant goats was not thought to be of value and no human ill health was reported. Thirty three goats were blood sampled and 23 showed high titres, indicating a high prevalence for Q fever within the herd.

In October 2008 further samples from aborting goats showed mixed infections but Coxiella burnetti was not considered to be the likely cause. Blood samples from 23 abortions in 2009 indicated C. abortus exclusively. Because the herd was expanding, the introduction of replacement goat kids raised questions about seroconversion despite a vaccination programme and over two years placenta samples were collected and stored: 62 samples (not all from abortions) yielded 57 positives, indicating a high secretion rate to the placenta.

Over 500 abortions have been recorded over the past five years. A severe Q fever abortion outbreak leads to a loss of breeding stock and the purchase of more stock compromises biosecurity.

Johne’s disease

Some thoughts were outlined by Benjamin Dustan (Westmorland Veterinary Group) on eradicating Johne’s disease from a goat herd. Giving the example of a farm producing Boer goats for meat and pygmy goats for the pet market, with the owners wanting a high-health status, the question was raised whether a Johne’s control programme can be delivered for goats.

Three sudden deaths on the farm followed a history of unexplained ill thrift. The whole herd (100 goats) was blood sampled and one positive was isolated, the test repeated and then the animal culled.

Diagnostic tests for goats are considered to be poor with ELISA showing negative until the disease is clinical. There are variable clinical signs due to the gut being unable to absorb nutrition and there is no treatment or cure.

Preventing faecal contamination for kids is an important practical measure and snatch kidding immediately after birth was discussed. Milk powder, to replace suckling, was used by some goat keepers but the use of artificial colostrum was considered to be “very risky”. More information is required about how to eradicate Johne’s from goat herds.

Free programme

The SAC Goat Health Scheme is requesting volunteers to take part in a free pilot programme of faecal sampling. Contact Nick Clayton (hon. secretary of the GVS) for details: nickclayton2@mac.com.

Dr Mike Coffey (SAC) updated delegates on progress towards a sire referencing scheme. Preliminary analysis of 2,405 whole lactation records from 829 dams and over 350,000 individual day milk records from 7,272 dams have indicated that goats have a genetic basis for milk yield. It will be possible to determine families and individuals that outperform counterparts. A substantial improvement in milk yield is possible: this may mean more milk produced or the same volume from smaller herds.

It is proposed to form a goat improvement group and to create a genetic improvement plan with an organised and planned movement of genetic improvement between herds. Traits that are of economic significance would be incorporated.

An in-depth appraisal of copper was presented by Nick Perkins (Delaware Veterinary Group) and Chris Livesey (VLA). A deficiency of copper can lead to weak kids at birth and initially bright kids can be affected later up to 28 weeks of age. It is important to have the correct level in the diet of the doe. Effects on the immune system increase the susceptibility to disease. Good liver function is important with copper toxicity and young kids are more susceptible than adults.

Extensively grazed animals are more at risk than concentrate fed and breed differences in cattle and sheep are recognised. Liver parasites and outwintering stress are known to reduce copper metabolism. Teart pastures are an issue in Somerset and it is recognised that the uptake of copper is variable from field to field. Cull animals can be an important resource for monitoring copper status and when investigating clinical problems.

“Don’t waste cull animals and check trace elements,” was one useful message.

Nodules

A whole range of experiences including goat warble (Asia), wattle cysts, and storing wine in goat scrotum bags (Germany) were amusingly detailed by Graham Duncanson. His title was “Nodules in goats with specific reference to the Norfolk Wenn”.

He explained that a Wenn referred to actinobacillus lesions in sheep on the marshes that respond to streptomycin injections. In general, the point was made that nodules may look insignificant but every lesion should be taken seriously.

Graham indicated that for diagnosis of nodules, go to the VLA. His serious approach to medicine is tinged with humour. He is impressed by a free sample of a product, the name of which escaped him, that was very good for sunburn on the noses of goats.

  • Full details of the papers will be published in the Goat Veterinary Society Journal