Seroprevalence of infectious bovine rhinotracheitis and brucellosis and their effect on reproductive performance of dairy cattle

A total of 332 dairy cow’s sera samples were collected from Kombolcha and Dessie districts of North Ethiopia to determine the sero-prevalence of infectious bovine rhinotracheitis (IBR), and Brucellosis. Sera samples were split into equal portions and competitive ELISA was used for testing IBR in the first portion while Rose Bengal test (RBT) and Complement Fixation Test (CFT) were used for detection of Brucellosis in the second portion. Sero-positivity was 25.6% (85/332) for IBR and 5.4% (18/332) for brucellosis with RBT which was found to be 0 (0%) by CFT. The prevalence of IBR was significantly influenced (P<0.001; OR=2.880) by parity with higher occurrence in multiparous compared to primiparous cows. IBR sero-positivity was highly associated (P<0.001) with repeat breeding, abortion and retained fetal membrane at odds ratio (OR) 8.833; 13.913 and 12.770, respectively. Similarly, IBR sero-positive animals had significantly higher (P=0.001) average days open, number of service per conception and calving interval than sero-negative animals. Conception rate at first service was higher (P<0.05, 74.4%) in sero-negative cows than in sero-positive dairy cows (25.6%). As latent infections and venereal transmissions are very common in IBR, its impact on the newly emerging urban dairy system would be significant unless an urgent control mechanism is designed. The associations of these reproductive infections with repeat breeding implies that they can seriously undermine the effort toward breed improvement in Ethiopia. Further studies with more detailed evaluation into various reproductive performance parameters should be the next step.