Reproductive Outcomes in High-Yielding Holstein Cows Following Administration of GnRH on Day 5 After Artificial Insemination

The objectives of this study was to assess the impact of a reproductive approach in high-yielding nulliparous and parous Holstein cows on the interestrus interval, estrus detection rates, conception rates, and pregnancy rates. The strategy involved giving GnRH on day 5 following artificial insemination (AI). For nulliparous cows, there appears to be no noticeable effect of GnRH therapy on the interestrus interval. In both groups, nearly all of the cows exhibited an 18–25-day cycle interval (P < 0.05). In the 18–25 day cycle period, the untreated multiparous cows exhibited the highest proportion (P < 0.05), while the treated group demonstrated the highest proportion (P < 0.05) in the 26–35 day cycle interval. The study found that the conception rate was higher in repeat breeder nulliparous and 3+ lactation treated Holstein cows compared with untreated ones. However, the cumulative heat detection rate, pregnancy rate and conception rates were similar in both groups (P > 0.05). Also, this study found that in the hottest months of the year, this therapeutic approach can't counteract the negative effect of heat stress in high-yielding dairy cows. Thus, it is not advised of using the hormonal method to create supplementary corpus luteum across the herd.