Bovine herpesvirus type 4 (BHV-4) infection in relation to fertility in repeat breeder dairy cows

Abstract

In this study, blood serum was collected from 162 repeat breeder (RB) dairy cows and tested by enzyme linked immunosorbent assay (ELISA). Of these samples, 87 were bovine herpesvirus type-4 (BHV-4) seropositive and 75 were BHV-4 seronegative. The prevalence of BHV-4 was determined as 53.70% amongst RB dairy cows. In the current study the seroprevalence was high. The average days open (DO) of pregnant BHV-4 seropositive RB cows was significantly longer (p<0.01) than that of pregnant BHV-4 seronegative RB cows, but was not significant for age of animals (p=0.186) or conception rate (CR) (p=0.14). The averages calving to the fourth insemination date (CFIDI) and age of nonpregnant BHV-4 seropositive RB cows was significantly higher (p< 0.05) than non-pregnant BHV-4 seronegative RB cows. In conclusion, a close fertility negative relationship existed between BHV-4 infections and fertility in RB dairy cows.