Date of this Version
2016 Nebraska Beef Cattle Reports
A study compared the effect of melengestrol acetate (MGA)-prostaglandin (PG) and 14- day controlled internal drug release (CIDR)- PG estrus synchronization protocols on estrus response and pregnancy rates of 311 d old heifers (n = 153). Pre-breeding BW was 50.1% of predicted mature BW. Percentage of heifers demonstrating signs of estrus was similar between synchronization treatments (CIDR vs MGA, 71.5 vs 77.4 ± 1.0%). Pregnancy rates to AI of heifers expressing estrus (n = 115) and final pregnancy rate were similar between CIDR and MGA synchronization treatments. Approximately half of these 311 d old heifers exposed to AI and bulls became pregnant.