Comparison of serological tests for detection of Brucella antibodies in cattle of an organized dairy farm

Brucellosis has long been recognized with high seroprevalence in Indian dairy herds. Serological surveillance followed regularly to monitor the status of the disease. Four serological methods viz., ELISA, RBPT, STAT and 2-ME tests were used to determine the seroprevalence of brucellosis in an organized dairy farm. Overall, 33.85%, 32.61% and 30.90% animals were diagnosed serologically positive, respectively by ELISA, RBPT and STAT. However, only 13.66% animals were diagnosed positive by 2-ME. Maximum numbers of seropositive cases were found in female animals, indigenous breed and in 6 to <9 yrs age group, respectively by all serological tests. ELISA diagnosed highest number of seropositive cases in different categories viz., females (36.41%), indigenous breed (21.13%) and 6 to <9 yrs (52.15%), respectively. Sex, breed and age of animals were found to influence the antibody titer (c2, p<0.05) of animals. Therefore, ELISA could be recommended as a screening test for cattle. However, at field level RBPT (k, 0.8597) and STAT (k, 0.8608) may be used for initial screening of the herd. In addition, 2-ME test must be used in parallel to other serological test to rule out the infection.