Journal of the American Veterinary Medical Association · 1973 · 25 citations · 0 references
Veterinary MedicineAnimal SciencesEndocrinologyArtificial InseminationReproductive EndocrinologyReproductive PhysiologyEstrous SynchronizationEstrus SynchronizationHeifer ManagementPregnancy BiologyRuminant ReproductionRuminant Reproductive MedicineCow Reproductive PhysiologyDairy Cattle Estrus SynchronizationHeifer Reproductive ManagementPregnancy Rate Assessment
SUMMARY Six experiments involving 677 heifers were conducted to evaluate the effect of 1,500 i.u. of a beeswax and oil standardized formulation of human chorionic gonadotropin ( hcg ) on pregnancy rate. Heifers in 4 of these experiments were treated with 6-chloroΔ 6 -17 acetoxy-progesterone ( cap ) to synchronize estrus. A single subcutaneous injection of 1,500 i.u. of hcg at the time of insemination increased pregnancy rates in 5 of 6 experiments (P < 0.05) with synchronized and with nonsynchronized heifers.