Control of reproductive function of cattle using cloprostenol.

Two intramuscular injections of cloprostenol were given 12 days apart to synchronise oestrus in a group of 47 heifers and following the second injection, 38 were found in oestrus in 2 to 6 days, 1 in 11 days and 8 in 22 to 27 days. The conception rate of the synchronised animals was 24 of 38 (63%). Twenty-nine heifers were given injections of cloprostenol in late pregnancy and parturition was induced with a latent period of 6 +/- 3 days when injected at 266 to 267 days. When injected at 254 to 262 days, 3 of 16 heifers (19%) were unresponsive and the remainder calved with a latent period of 12 +/- 6 days. The survival rate of calves from induced heifers was 71% with 80% survival from controls. Approximately 50% of the induced heifers, and none of the controls, retained their foetal membranes.