Can you afford £20,000 cost of a BVD outbreak?

3 October 1997

Can you afford £20,000 cost of a BVD outbreak?

High costs of BVD disease,

poor control of sheep scab,

and economics of heat

synchronisation were to the

fore at last weeks British

Veterinary Association

congress, in Edinburgh. Jessica Buss reports

CATTLE producers fail to appreciate the devastating effects of bovine viral diarrhoea, despite it being widespread in the UK with 95% of herds being infected.

So said Prof Joe Brownlie of the Royal Vet College, at the annual BVA congress in Edinburgh.

The disease has a major effect on animal health, causing infertility, abortion, stillbirths and mucosal disease in calves which is fatal. It is estimated to cost the UK cattle industry £70m a year and is thought to be present in cattle populations worldwide.

"It is important to try and get rid of it. It would cost a 150-cow BVD free dairy herd that brings in an infected animal £20,000 for a single outbreak," said Prof Brownlie.

"The main reservoir was a persistently-infected animal in the herd." It would transmit the infection to cows or heifers in early pregnancy when it either causes abortions or infected calves are born. Acutely infected animals can suffer a 20 to 40% drop in fertility, he added.

Infected animals make antibodies to depress the virus in the bloodstream. But the antibodies are slow to build up and can diminish, allowing reinfection to occur, he warned.

"Other countries will shut borders to avoid bringing in BVD," said Prof Brownlie. Eradication schemes for BVD have begun in Sweden, Denmark, Norway and Finland.

Sweden has a voluntary eradication scheme with 55% of dairy herds in the scheme of which 86% are now disease-free. Denmark has also started slaughtering persistently-infected animals and has separate sales for BVD-free cattle.

Identifying the disease is cheap and simple, and there is a vaccine. He suggested a control strategy of eliminating persistently-infected animals and vaccinating heifers to ensure they have immunity in early pregnancy.

Calves would then need testing, either before giving colostrum or after four-months-old, to ensure they are not persistently infected. Bulls must also be tested for BVD as it is transmitted via semen.

But once a herd is free from the disease it is susceptible to infection, warned Prof Brownlie. Careful management would then be needed to ensure no infection is brought in on cattle, sheep or goats, or vaccination and testing would need to continue.

"The advantages of eradicating BVD are well worth the effort." He claimed that there had been reports of pregnancy rates increasing from 50 to 80% after vaccination with two doses of Bovidec. Other herds were said to have seen dramatic improvements in herd health.

How healthy are your calves? BVD disease costs the industry £70m a year but largely goes unnoticed.

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