Influence of Human Chorionic Gonadotropin on Pregnancy Rates in Lactating Dairy and Beef Cows

Abstract
Single s.c. injections of 1500 IU human chorionic gonadotropin or placebo injections were given at insemination in lactating dairy and beef cows to determine their effects on rates of pregnancy. Pregnancy rates at 1st service in 161 control and 145 treated dairy cows were 52.8% and 44.8%, respectively. Similar rates for 136 control and 145 treated beef cows were 54.4% and 54.5%. Injections of human chorionic gonadotropin were not effective in stimulating conception rates in lactating dairy or beef cows under field conditions.