The Maintenance of Early Pregnancy in the Ovariectomized Ewe by Injection of Ovarian Hormones

Abstract

Studies were made on the maintenance of early pregnancy in the ewe by means of hormone injections; a total of 67 treated and control ewes were autopsied 25 days after breeding. Treated ewes were ovariectomized 84 hours after breeding and given daily hormone injections until autopsy. Progesterone and estradiol in the ratio of 100 to 1 were administered to 14 ewes but pregnancy was maintained in none. Fourteen other ewes were given the same dosages of progesterone only and pregnancy was maintained in four. Fourteen of 21 ewes given 1 mg. progesterone and 0.25 meg. estrone daily per 5 lb. body weight were pregnant at autopsy as compared to 14 of 18 untreated and unoperated ewes. Embryos from ewes receiving progesterone and estrone were significantly heavier than those from untreated ewes (166 mg. av. as compared to 126 mg.).