EPIDEMIOLOGIC CHARACTERISTICS OF BOVINE HERPESVIRUS-1 INFECTIONS DETERMINED BY BULK MILK TESTING OF ALL DUTCH DAIRY HERDS

November 1994 and tested for the presence of bovine herpesvirus 1 (BHV -1) antibodies with a gB-blocking ELISA, Sixteen per cent of the herds had a negative BHV-1 status in the bulk milk, Farms with only dairy c ows were 1.9 times more likely to have a negative or weakly positive B HV-1 status than herds which also had beef/veal animals, Farms in area s containing less than one herd/km(2) were 1.5 times more likely to ha ve a negative or weakly positive BHV-1 status than herds in areas with more than three herds/km(2). Differences in numbers of animals per un it area were not significantly associated with BHV-1 status, The proba bility of herds having a negative or weakly positive BHV-1 status decr eased linearly with herd size by a factor of 1.2 per 10 animals, The p urchase of stock was significantly associated with a negative or weakl y positive BHV-1 status, but there was an interaction between farm typ e and purchase of stock, For farms with both dairy and beef/veal anima ls there was a weak association between the purchase of stock and BHV- 1 status. For pure dairy herds the probability of having a negative or weakly positive BHV-1 status decreased linearly with the numbers of p urchased stock by a factor of 1.3 per 10 animals purchased.