Milk or blood (serum) can be used to test for the presence of antibodies to BVD. BVD antibodies only indicate that an animal has been infected with BVD virus at sometime in its life. In most cases animals which are positive for the presence of antibodies are not persistently infected with the disease.
Demonstration of BVD antibodies in milk indicates that cows have been have previously been vaccinated or been exposed to animals which were carrying BVD.
BVD Antibody detection (BVD Ab) in serum is most useful for monitoring exposure of juvenile animals to persistently infected BVD animals. Calves less than 6 months of age should not be checked for BVD antibodies as they are likely to have maternally derived antibodies from the mother’s colostrum.