DIAGNOSTIC STUDIES OF ABORTION IN DANISH DAIRY HERDS

Diagnostic findings in 218 aborted bovine foetuses are reported. The m aterials were examined in a matched case-control study of 69 Danish da iry herds with a sudden increase in the number of abortions and a corr esponding 69 control herds. Foetuses aborted during the subsequent 6-m onth period were examined to identify the cause of abortion if possibl e. A total of 186 specimens were submitted from case herds and 32 from control herds. A likely cause of abortion was diagnosed in 73 foetuse s. The most common cause was bovine viral diarrhoea virus (BVDV: 13%) followed by Neospora caninum infection (10%), mycosis (5%) and Bacillu s licheniformis infection (4%). Foetal and/or placental lesions were f ound in a further 27 cases. Only BVDV infection and neosporosis were d iagnosed in more than one foetus per herd and only protozoal associate d abortions occurred significantly more frequently in the case, rather than in the control, herds.