The effect of subclinical bovine herpesvirus 1 infection on fertility of cows and heifers

The aim of this study was to determine the serological prevalence of bovine herpesvirus 1 (BHV-1), and describe whether natural subclinical infections will lead to fertility losses in dairy cows and heifers in Burdur, Turkey. BHV-1 prevalence was 11.94% (201/24) and 14.60% (89/13) in cows and heifers, respectively. Conception rate (CR) was higher in BHV-1 serologically negative cows (38.98%) than BHV-1 positive cows (33.33%) but the difference was statistically insignificant (P>0.05). However, CR was higher (P>0.05) in BHV-1 serologically positive heifers (84.61%) than BHV-1 negative heifers (56.57%). Average open days period (OD) of BHV-1 serologically positive cows (99.3 ± 16 d) was different from BHV-1 negative cows (82.0 ± 3.8 d) (P < 0.05). Average for the first service (FSA) of BHV-1 serologically positive heifers (18.01 ± 1.1 mo) did not differ from BHV-1 negative heifers (18.0 ± 0.3 mo) (P > 0.05). Results of the current study showed that BHV-1 serologically positive cows have required for successful conception about 17 days more than negative cows.