PREVALENCE OF ANTIBODIES TO BOVINE VIRUS DIARRHEA VIRUS AND OTHER VIRUSES IN BULK TANK MILK IN ENGLAND AND WALES

Bulk tank milk samples from 1070 dairy herds in England and Wales were tested by ELISA for antibodies to bovine virus diarrhoea virus (BVDV) . A subset of 341 herds was tested by ELISA for antibodies to bovine h erpesvirus 1 (BHV-1), bovine respiratory syncytial virus (BRSV) and bo vine coronavirus (BCV), None of the herds had less than 40 dairy cows and none had been vaccinated against BVDV. The prevalence of BVDV anti body-positive herds in the national population was estimated at 95 per cent and approximately 65 per cent of the herds had a high level of b ulk tank antibody suggestive of recent infection with BVDV, Dairy herd s in East Anglia and the south-east of England had a significantly low er risk of being BVDV antibody-positive than herds in the rest of Engl and and Wales. However, these regional differences tended to diminish with increasing herd size. Around 69 per cent of the herds were BHV-1 antibody-positive and all the herds were antibody positive to BRSV and BCV. Comparison with earlier serological surveys revealed that there had been little change in the prevalence and distribution of BVDV anti body-positive herds in England and Wales over the last 20 years, but t hat there had been an increase in the prevalence of BHV-1 antibody-pos itive herds.