Seroepidemiology and Risk Factors of Brucellosis in Dairy Cattle (Bos indicus) and Buffaloes (Bubalus bubalis) in Gujarat, India

Bovine brucellosis is an economically important zoonotic disease that adversely affects reproductive performance and productivity in dairy animals. The present study was undertaken to determine the seroprevalence of brucellosis in dairy cattle and buffaloes in Gujarat, compare the diagnostic performance of the Rose Bengal Plate Test (RBPT) and indirect enzyme-linked immunosorbent assay (ELISA), and assess the association of age, breed and reproductive disorders with seropositivity. A total of 740 serum samples (697 cattle and 43 buffaloes) collected from 42 villages across three districts were screened by both tests. Overall seroprevalence was 5.14% by RBPT and 12.03% by indirect ELISA, with ELISA detecting substantially more seropositive animals and showing only moderate agreement with RBPT. Seropositivity increased progressively with advancing age, being highest in animals older than 12 years, and varied among breeds, with Gir cattle and Mehsani buffaloes recording the highest prevalence. Animals with reproductive disorders, particularly abortion and repeat breeding, showed markedly higher seropositivity than clinically normal animals. The findings indicate that indirect ELISA is a more sensitive assay than RBPT for detecting bovine brucellosis and support its incorporation into routine surveillance programmes, with priority screening of older animals and animals with reproductive disorders.