Eye-catching theory that BVD infection linked to increased bTB vulnerability, but many farmers missing out

A majority of dairy and beef farmers are missing out on a buy-one-get-four-free disease prevention deal and, as a result, will be losing significant sums of money. That's according to veterinary surgeon Ben Pedley from the Willows practice in Cheshire, speaking at a professional development meeting of farm animal vets.

He said the primary disease in question, Bovine Viral Diarrhoea virus (BVD), was known to be present in 95% of dairy and 87% of suckler beef herds. But according to another speaker, William Sherrard MRCVS of Pfizer Animal Health, a major concern given the high percentage of herds known to have the disease was that only about one-in-three cows nationally was vaccinated against the disease.

For farmers, what made the BVD threat difficult to assess were the varied and sometimes vague nature of the symptoms, explained Ben Pedley. "When you train as a vet, impaired cow fertility together with deformed or still-born calves are the main signs you're told to look for," he said.

"But when you practice as a vet, many farms find that vaccinating against BVD reduces digestive infections and pneumonia in calves. Others see cow fertility improve while some enjoy reduced mastitis infections. And in bovine TB hot-spot areas, the most eye-catching theory currently is that BVD-infected herds are more susceptible to bTB infection."

He cited a paper presented to a British Cattle Veterinary Association Congress by Chris Watson of the Wood Veterinary Group in Stroud, Gloucestershire, which set out a possible link between BVD and increased bTB-susceptibility[3]. Mr Pedley explained that the factor linking all these diseases was that BVD infection impaired the immune system of cows and their calves.

To identify whether a herd was infected with BVD, milk or blood or tissue samples could be tested and Ben Pedley said his practice actively encouraged clients to screen their herds. He reckoned BVD vaccination in a dairy herd was worth more than two pence per litre from improved productivity and reduced disease treatment costs. In a suckler herd, he cited SAC figures of £40 per cow per year gained. He advised farmers wanting to check their herd's BVD status to ask their veterinary surgeon as a matter of urgency. The meeting was sponsored by Pregsure BVD vaccine.