Effect of Human Chorionic Gonadotropin on Pregnancy Rate of Heifers, When Used Under Field Conditions

Abstract

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.