Evaluation of single shot prostaglandin F2α analog (dinoprost tromethamine) for estrus synchronization in cattle with corpus luteum

An experiment was conducted from June 2022 to April 2023 at Debrezeit Agricultural Research Center to evaluate the effectiveness of single shot prostaglandin based estrus synchronization protocol in Boran, Boran*Holstein-Friesian crosses, and Holstein-Friesian cattle upon manual detection of mature corpus luteum (CL). A total of 120 animals (80 cows and 40 heifers) with detected CL from different age, body condition (BC), parity, days in milk, and lactation status were included in the experiment. A single injection of 5 ml LUTALYSE® Injection (dinoprost tromethamine, a prostaglandin F2α analog) was used to synchronize the animals. The observed estrus response and conception rate were 83.3% and 73.0%, respectively. Among the predictor factors considered, BC score significantly influenced both estrus response and conception rates, while days in milk (DIM) had significant effect on conception (p <0.05). Estrus response and pregnancy rates were higher in animals with better BC, and cattle with >60 DIM had significantly higher conception rate compared to those with less DIM. Both estrus response and pregnancy rates were not significantly different between cows and heifers, as parity had no significant association (p >0.05) with both outcomes. The result showed that manual per rectal detection of CL and injection of a prostaglandin analog were effective in inducing heat. Therefore, synchronization with a single injection of LUTALYSE in heifers and cows after manual detection of mature CL could minimize drug cost and can achieve optimal results.