Experiments on the use of chronic gonadotrophin (pregnancy urine extract) for the treatment of sterility in dairy cattle

Abstract

1. The fertility of three sterile bulls was restored by injections of human pregnancy urine extract (P.U.).2. Cows which failed to exhibit oestrus were treated by injections of P.U. Three out of five cows responded within 24 hours to intravenous injections of 5 c.c. P.U. (2500 rat units) and one out of four to an injection of 3 c.c. P.U.Two out of five cows responded immediately to a series of three intramuscular injections of 2 c.c. P.U. and one cow responded to a single intramuscular injection of 2 c.c. P.U. In addition four cows failed to respond immediately to four intramuscular injections of 2 c.c. P.U.3. Evidence was obtained which shows that treatment with P.U. at the time of service increases the fertility of cows which show regular oestrus but nevertheless fail to conceive. It is believed that this condition is often due (a) to failure to ovulate, and (b) to deficiency of progesterone following ovulation.We are grateful to Prof. R. Rae and Mr K. W. C. Campbell for their co-operation. Part of this work was carried out during the tenure by one of us (H.M.S.W.) of a Research Grant from the Ministry of Agriculture and Fisheries.