Artificial induction of lactation in ewes: the importance of prolactin and growth hormone for initiation of lactation induced with prostaglandin F2α

Abstract

Abstract A single subcutaneous injection of prostaglandin F2α initiated secretion of substantial quantities of milk when given to non-pregnant ewes with mammary glands developed by prior treatment with ovarian steroids. A dramatic but transient increase in the levels of prolactin and growth hormone in plasma was observed. Ewes injected with ergocryptine 24 h before injection of prostaglandin F2α produced lower, but not significantly lower, yields of milk, even though the levels of prolactin in plasma were reduced to negligible values, whereas there was no effect on the increase in levels of growth hormone. Control ewes not injected with prostaglandin F2α, secreted only trivial volumes of milk, with levels of prolactin and growth hormone in plasma remaining low.