Immune response of buffaloes to vaccination with Brucella abortus strain 19.

The immune response of buffalo calves and heifers to a full or half dose of Brucella abortus strain 19 vaccine was studied. Buffalo calves developed high serum agglutination test (SAT) titres following full dose vaccination. These titres declined more rapidly in calves of six months of age than in calves of eleven to twelve months of age. Specific immunoglobulin G titres, as measured by 2-mercaptoethanol-treated serum agglutination, declined much earlier than SAT titres. Buffalo heifers vaccinated with a full or half dose developed high SAT titres. The rate of decline of SAT titres in heifers was much slower than in calves. Vaccination with a half dose did not appear to offer any advantage in terms of disappearance of SAT titres.