17 August 2001

Pooling colostrum may spread Johnes disease

POOLING colostrum from a number of cows in an attempt to prevent diseases, such as rotavirus, in calves could actually be spreading other diseases.

In a letter to Vet Record, midlands-based vets Steve Borsberry and Iain Piggot raise concerns about the potential spread of Johnes disease through colostrum, particularly when it has not yet been diagnosed in the herd.

Many producers mix colostrum from cows for ease of storage and to ensure protection against calf diseases for which all or some of a herd of cows are vaccinated, says Mr Borsberry. "But if just one cows milk is contaminated with Johnes she could infect up to a dozen calves.

"This disease follows an unusual pattern because it is picked up by cattle in their first few days of life, but does not develop until two or three years later." It also appears that only a small dose is needed to cause disease.

He advises checking a herds disease status before pooling colostrum to ensure the practice is the best option. This would require blood or milk tests and a knowledge of the farms disease history.

The vets also question whether pooling colostrum could risk spreading other diseases, such as neosporosis. &#42