22 March 2002

Greater disease status knowledge cuts costs

Knowing the disease status of dairy cows is the first step

towards minimising the costs of poor herd health, which

can run into many pence/litre, as Jessica Buss finds out

INFECTIOUS disease costs can quickly destroy the profits of dairy farms, but awareness of which diseases are present in herds remains poor.

In a survey of 32 of the Leicester-based Park Vet Groups clients, most admitted to not knowing whether many of the diseases being surveyed were present (see graph).

Reporting the results to clients, group vet Peter Orpin said the survey focussed on common infectious disease not present on all farms, including leptospirosis, bovine viral diarrhoea, infectious bovine rhinotraceitis, husk, digital dermatitis, neospora and Johnes.

"These are diseases where neighbouring farms can differ in their status, so they require different courses of action. Foot-and-mouth has shown how quickly viruses can move between herds. Many other diseases move in a similar way.

"Other infectious diseases, such as mastitis and pasturella are equally economically important, but are common to most farms."

The initial stage of the survey asked producers what diseases were present or vaccinated against on their farms. On a sample of farms which didnt know whether a disease was present, milk tests were taken to find out whether a number of the diseases were present.

Mr Orpin stressed the aim was not to sell vaccine, but to help put suitable health plans in place for all herds.

"To reduce future disease costs, farms must have a health plan and be clear about what diseases are in the herd now, which ones you want to treat, get rid of or keep out. The biggest cost is just living with the disease. Costs of preventing diseases are often low.

"Where we had done technology transfer on a disease, including BVD, we found better awareness of it.

"But the opposite was true for diseases, such as IBR, which we hadnt previously made an effort to inform people about," he said.

However, he was mystified that despite frequent pestering and offers of free investigations, many clients were unaware of whether diseases were present. They appeared to be nervous about knowing what diseases their herds had. Many also proved to be lapsed vaccinators.

Without knowing disease status, it was impossible to plan for the future. "Herds that are negative to infections need to keep them out with a herd biosecurity plan, as part of a herd health plan." He uses the British Cattle Vet Association plan as a base, and offers a discount on medicines to clients with a plan in place.

"With no major cattle health scheme, each farm is responsible for sorting out its own. The cost of advice now is likely to be less than the cost of treatment later."

Preventing disease, which may include vaccination or improved biosecurity, will typically cost 10-20 times less than treatment, says Mr Orpin (see table).

Producers should be concerned about Johnes disease. The survey shows that 10% of the practices clients have identified it in the last three years and the national incidence is increasing, he adds.

"Buying in one cow carrying Johnes disease can saddle a typical 7000-litre herd with 0.3p-0.5p/litre of costs for 10 years, even though it appeared healthy."

Because the incubation period can be three or four years and these animals can then infect others for about six months, it takes a long time to eradicate.

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