Evaluation of a melengestrol acetate and prostaglandin F2α system for the synchronization of estrus in beef heifers

摘要: This study was conducted to determine the efficacy of feeding melengestrol acetate (MGA) for 14 days and administering prostaglandin F2α (PGF) 17 after MGA synchronize or induce estrus in yearling beef heifers. The involved 56 Angus (n = 19), Hereford 15) Simmental 22) heifers that were assigned by breed pubertal status either MGA+PGF control groups. Heifers synchronized group fed 0.5 mg per head day from a grain carrier injected with 25 mg, i.m. PGF last daily MGA. Control without not treated PGF. classified as when concentrations progesterono serum exceeded 1 ng/ml 2 samples collected prior initiation treatments. Blood 7 before on treatment began administered. Progesterone elevated ( > ng/ml) 61% (1728) MGA+PGF-treated However, progesterone at time administered differed (P<0.05) between Concentrations 100% (2828) 71% (2028) (P<0.05). All inseminated 12 hours first detected estrus. Twenty-two 28 (79%) exhibited within 6 compared 9 (32%) conception rate service did differ groups (64% 67%, respectively). Synchronized pregnancy rates higher than (1428, 50% vs 628, 21%). Increased during period among demonstrate this use synchronization. Moreover, may have potential effect inducing puberty breeding age