Analysis of the linkage between viral, bacterial, and protozoal infections and the level of reproductive losses in dairy herds in the Ural region

Abstract

The analysis of the linkage between infection of dairy herds in the Ural region with BVDV, BHV-1, C. abortus and N. caninum with indices of reproductive function and reproductive losses was performed. The results of studies of 1453 samples of biological material by Elisa, PCR and Real-Time PCR were taken into account. The level of BVDV infection in animals of various physiological groups in the examined farms ranged from 15.6 to 66.7%, and the seroprevalence of the BHV-1 field strain was 31.8%. The amount of seroprevalent to C. abortus animals in dairy herds was 55.1 %, to N. caninum-43.3%. The lowest rates of fertilization were found in farms with simultaneous circulation of chlamydia and neosporosis pathogens and in mono-chlamydia infection. In these same herds, there was a longer post-partum interval. The highest mean rate of abortions in cows and heifers was in farms with N. caninum circulation, as well as in mixed infections, with increased action of infectious factors. In the analysis of viral infections, it was established that the highest level of perinatal losses was seen in the presence of BVDV.