ANTIBODY DYNAMICS IN HOLSTEIN FRIESIAN HEIFERS VACCINATED WITH BRUCELLA ABORTUS STRAIN 19, USING SEVEN SEROLOGICAL TESTS

ABSTRACT The serological response induced by Brucella abortus strain 19 was evaluated in 52 Holstein females from a brucellosis-free herd using seven serological tests. Each calf was vaccinated at an age of 4 and 8 months old with 3 × 1010 CFU B. abortus S19 and the antibody response was determined as the proportion of positive results to each test. The antibody dynamics, measured with the buffered plate antigen (BPA) test and the rapid automated presumptive (RAP) test, were similar. The proportion of positive reactions in these tests reached 100% one week after vaccination and remained at this level for seven weeks, after which the proportion of positive samples slowly declined to 8% (BPA) and 2% (RAP) at week 50. The response in the indirect enzyme immunoassay (i-ELISA) was similar, but shorter than that observed with the BPA/RAP. The antibody dynamic, measured using the seroagglutination test (SAT) in parallel with the 2-mercaptoethanol (2-Me) test and the complement fixation test (CFT) were similar to...