Comparative Efficacy of Ovsynch and Presynch-Ovsynch Protocols on Estrous Expression and Pregnancy Outcome in Holstein Friesian Cattle

Abstract

Efficient reproductive management is essential for improving fertility and maintaining productivity in dairy cattle, as delayed conception can prolong the calving interval and reduce reproductive efficiency. The present study evaluated and compared the effectiveness of Ovsynch and Presynch-Ovsynch protocols in Holstein Friesian cattle, with particular emphasis on estrous response, onset and duration of estrus, estrous intensity, total estrous score, and pregnancy outcome. Fourty healthy Holstein Friesian cattle were randomly divided into two equal groups of 20 animals. Group A received the Ovsynch protocol, whereas Group B was subjected to the Presynch-Ovsynch protocol. Estrous behavior was monitored through visual observation, and the onset, duration, intensity, and total estrous score were recorded. Pregnancy was subsequently confirmed using the established reproductive diagnostic procedure. Detectable estrus was observed in 60% of cows in the Ovsynch group and 80% in the Presynch-Ovsynch group. The mean onset of estrus was 50.40 ± 0.75 h in Ovsynch-treated cows compared with 63.04 ± 1.21 h in Presynch-Ovsynch-treated cows, while the corresponding estrous duration was 16.10 ± 1.13 h and 21.81 ± 0.53 h, respectively. Strong estrus was expressed by 45% of Ovsynch cows compared with 70% of Presynch-Ovsynch cows, whereas weak estrus was observed in 35% and 10%, respectively. The total estrous score was considerably higher in the Presynch-Ovsynch group (132.3 ± 15.123) than in the Ovsynch group (66.2 ± 10.870). Pregnancy was confirmed in 45% of cows receiving Ovsynch and 70% of those receiving Presynch-Ovsynch. The Presynch-Ovsynch protocol resulted in stronger and more sustained estrous expression, a higher total estrous score, and numerically improved estrous response and pregnancy rate compared with Ovsynch. It was concluded that Presynch-Ovsynch may provide a more effective reproductive management approach for enhancing estrous expression and potentially improving fertility in Holstein Friesian cattle.