British Cattle Veterinary Association

In a series of studies the roles of cattle exposure to bovine tuberculosis (bTB) from other cattle and from the farm and the impact of test and cull control are presented. One of the studies is of four counties in England, two with a long history of herd breakdown (HBD) with bTB and two with a history of HBD from the mid 1990s. We conclude that in an unstable situation bTB testing leads to a delay in detection of herds with cattle that are positive to the skin test. At least some of the HBD was most likely to be caused by purchase of infected cattle. In a second study, farms that were depopulated during FMD in 2001 and subsequently restocked were considered. Reformed herds that included cattle purchased from herds located in areas that were tested at less than 2-year test intervals for ten years before 2001 were at greater risk of HBD.