14 November 1997

BVD virus on the increase

DAIRY producers are advised to watch out for symptoms of bovine viral diarrhoea following breakdowns in natural immunity and increased incidence of the disease.

So warns Nantwich-based vet Denis Leonard of Wilson McWilliams and Partners, who has seen more BVD breakdowns over the past few months than in previous years.

Increased incidence may result from new BVD strains entering the UK, to which our national herd has no immunity, he says. Alternatively, breakdowns in immunity can occur when carriers in the herd, leaving younger animals without immunity and more susceptible to the disease.

BVD symptoms include scouring, weight loss and pneumonia in cows and calves, abortions in cows, and mucosal disease in calves.

Vaccination will control BVD strains, including those from Europe, he says. It will also eliminate the risks of challenge on pregnant animals with no immunity from carriers in the herd. Although vaccination seems expensive, it is cheap compared with BVD losses.n