Johne’s disease in goat

Press, 12 July 1985, Page 22

Johne’s disease in goat

It is unlikely the source of caprine Johne’s disease, discovered recently in a six-year-old dairy goat in Central Canterbury, will be pinpointed.

The infected animal was one of 20 bred on a property which has no history of Johne’s disease after years of producing milking goats.

A M.A.F. veterinary investigation officer at Lincoln, Mr Bob Gumbrell, said it is not known why one goat became infected on that farm. He said the animal lost condition and had intermittent diarrhoea for six months before developing submandibular oedema. Typical gut lesions of Johne’s disease were found during a post-mortem. Mr Gumbrell said the goat was the third found in the region with the disease. An infected goat was found in the Golden Bay area and is known to have been, bought from Canter-

bury. The other was discovered at a M.A.F. research unit. Mr Gumbrell said Johne’s disease is thought to be present on 80 per cent of sheep farms on the Canterbury plains and foothills and has been recorded in deer, cattle and now goats.

The cost to dairy farmers of the mysterious and incurable disease is the focus of a M.A.F. research programme at Wallaceville Research Station, in Wellington.

Johne’s disease is related to tuberculosis and it causes cattle to waste away. Scientists\believe it affects milk yield and butter fat production.

An animal health scientist, Dr Geoff DeLisle, said the research is being carried out on six North Island farms which are known to carry Johne’s disease.

The programme will compare the total milk yield

and butter fat production of a diseased group of cows with a control group free of the problem. Cattle do not show any signs of having contracted the disease until at least two years old, but more commonly three or four years old.

Lesions caused by the disease are found in the animals’ gastro-intestinal tract and the baccillus is passed out in the faeces to other animals. “There is no treatment,

but there is a vaccine. It is not used in New Zealand with the exception of one farm where it is being used as an experiment,” Dr DeLisle said.

Problems are created by the Vaccine, which if used widely would have to be stringently controlled. “Vaccination sensitises the animal to the tubercolon skin test which becomes an added complication when testing for TB.” /