Reproductive responses of primiparous and multiparous Holstein cows submitted to presynch-ovsynch protocol

Abstract The specific objective of this study was to determine the reproductive responses of primiparous (n = 446) and multiparous (n = 726) Holstein cows submitted to 12-day presynch-ovsynch protocol under the Egyptian circumstances. Distribution of inter-estrus intervals (IEI) and conception rate to first insemination (FICR) was compared between primiparous and multiparous cows. Furthermore, Seasonal variations of heat detection rate (HDR), conception rate (CR) and pregnancy rate (PR) were investigated. Short IEI tended to be higher in multiparous cows (23.8 vs 20.44%, P = 0.09) compared to primiparous cows. In addition, the incidence of prolonged IEI was decreased from 21.53% in multiparous cows to 16.77% in primiparous cows. On contrary, normal length IEI was 62.78% in primiparous cows, higher than that observed in multiparous cows (54.67%). Moreover, primiparous cows inseminated earlier postpartum (