Abstract
In this study, blood serum and leucocyte samples were collected from 400 Holstein heifers, all of which appeared healthy. Antibodies (Ab) against bovine viral diarrhoea virus (BVDV) were detected in 57 serum samples, and BVDV antigen (Ag) was detected in 38 leucocyte samples. There were statistically important differences between the average first insemination ages (FIT) of the BVDV (Ag‒/Ab+) heifers (P<0.0001) (pregnant P<0.05, non-pregnant P<0.0001) and BVDV (Ag‒/Ab‒) heifers. The average conception rates (CR) of BVDV (Ag‒/Ab+) heifers and BVDV (Ag‒/Ab‒) heifers were not significant statistically. There were statistically important differences of average FIT between persistent infected (PI) BVDV (Ag+/Ab‒) heifers (P<0.0001) (PI pregnant P<0.05, PI non-pregnant P<0.0001) and BVDV (Ag‒/Ab‒) heifers. No significant differences of average CR between PI BVDV (Ag+/Ab‒) heifers and BVDV (Ag‒/Ab‒) heifers were found. The differences of average FIT between BVDV (Ag+/Ab+) (P<0.0001) (non-pregnant P<0.0001) and BVDV (Ag‒/Ab‒) heifers were important statistically. But while there were no BVDV (Ag+/Ab+) pregnant heifers, the differences of average CR between BVDV (Ag+/Ab+) pregnant heifers and BVDV (Ag‒/Ab‒) heifers were found statistically important (P<0.0001). We conclude that fertility is affected in heifers with BVDV (Ag‒/Ab+), BVDV (Ag+/Ab‒) and BVDV (Ag+/Ab+).
