Congenital brucellosis in cattle associated with localisation in a hygroma.

A heifer born to a cow experimentally infected with Brucella abortus strain 544 and reared in isolation from its birth was found infected. Antibodies appeared when it was 10 months old. The heifer calved normally. Brucella abortus of the same characteristics as strain 544 was recovered from a hygroma and from lymph nodes and udder. Five heifers out of 55 (about 10 per cent) born to infected dams and reared in isolation from their birth were found to be infected.