The influence of selected herd factors and a badger-intervention tuberculosis-control programme on the risk of a herd-level trade restriction to a bovine population in Ireland.

The risk of a trade restriction to cattle herds between 1990-1994, as a result of failing the tuberculin skin test or disclosure of visible lesions in the abattoir, was compared in two areas in East Offaly, Ireland. Cattle herds from the Project area where badgers were systematically removed over a 7-year period (1989-1995) were compared to herds from a Control area where no wildlife-intervention programme had taken place. A Cox proportional hazard model indicated, for example, that the risk of a herd-level trade restriction to herds with 30 animals in the Control area was 1.4 times the risk to similar-sized herds in the Project area. The study provides evidence that a badger-control programme is effective in reducing the risk of a trade restriction to cattle herds as the badger represents an important reservoir of Mycobacterium bovis infection for cattle.