The serological BHV1 status of dams determines the precolostral status of their calves

Precolostral calves and their dams were serologically investigated for the presence of antibodies against Bovine Herpesvirus 1 in diagnostic tests wit h a very high sensitivity and specificity. Although the syndesmo-chorial ty pe of placenta of ruminants does not transfer gamma globulins, a large numb er of calves had antibodies, in most cases in a very low concentration, Sig nificant correlations were found between the serological status of the dam, the status of the calf, and the titre of antibodies. Oral intake of matern al blood by the calf at birth or transmission or leakage of maternal antibo dies during pregnancy might be possible causes of precolostrally positive c alves. From the results it is concluded that to reduce the risk of obtainin g BHV1-positive calves, BHV1-negative dams should be selected for breeding purposes.