British Cattle Veterinary Association

Coccidiosis had been known as a significant problem in cattle since at least the early 1940's. Initially it was considered to be a disease of limited clinical importance, mainly affecting calves kept indoors in unhygienic conditions. VIDA data for diagnoses from faecal samples showed a rapid rise in positive levels for coccidiosis from 1993 to 1997, so that levels found positive were double to those seen pre-1993. This suggests some factor changed rapidly in the mid 1990's and it is postulated that this was the result of the removal of antimicrobial growth promoters (AGPs) by most major feed manufacturers. Data show that numbers of positive diagnoses is high in the seven months May to November and low from December to April.