The Use of the Antiglobulin Test in the Diagnosis of Bovine Brucellosis

Abstract

Summary The levels of agglutinating and non-agglutinating Brucella antibody in the serum of 6 calves and 5 cows following vaccination with Brucella abortus strain 19 were measured by the standard tube agglutination test and the antiglobulin procedure using polyvalent and mono-specific antiscra. The titres and antiglobulin specificity of antibody observed in these animals were compared with those from cows in a Bruccella-infected herd. In the vaccinated cows and calves peak levels of agglutinating antibody occurred earlier than those of non-agglutinating antibody. Most of the non-agglutinating antibody was associated with IgG1; IgG2 antibody appeared transiently and had disappeared by 188 days after vaccination. Only low levels of antibody were detected in whey from the vaccinated cows. Serologically positive cows from the infected herd generally showed much higher levels of nonagglutinating antibody in their serum. Most of this antibody was associated with IgG1, but significant amounts of IgG2 antibody were also present. IgG1 antibody predominated in whey from infected cows. It is considered that the antiglobulin test using specific antiglobulin reagents is potentially useful for the classification of cattle of unknown vaccination status.