Synchronization of estrus in virgin beef heifers using melengestrol acetate and PGF2α: an efficacy comparison of cloprostenol and dinoprost tromethamine

摘要: Abstract This study compared the efficacy of two sources PGF 2α on reproductive performance virgin beef heifers, after synchronization estrus using melengestrol acetate (MGA) and . Angus-based heifers ( n =1002) in five herds were fed 0.5mg per head day MGA for 14 days. Nineteen days last feeding, randomly assigned to receive (i.m.) either cloprostenol =504; Estrumate ® , E) or 25mg dinoprost tromethamine =498; Lutalyse L) as a source exogenous Heifers observed twice daily 5 signs artificially inseminated 8–12h later, except herd A, wherein animals not detected by 80h mass-mated no longer monitored estrus. equally P >0.1) effective among all response variables evaluated, including (E, 89% L, 86%), conception rate 67% 67%), synchronized pregnancy 61% 57%). Synchrony was affected source, peak occurred 60h post-PGF both treatments. Conception timed insemination different Estrumate- Lutalyse-treated within A (14%, 4/28 7%, 2/29, respectively). Herd had significant