THE EFFECTS OF CORTISONE ACETATE ON THE LENGTH OF THE GESTATION PERIOD AND THE SURVIVAL OF FOETAL SCOTTISH BLACKFACE LAMBS

Abstract

Van Rensburg (1967) injected cortisol acetate in doses of up to 50 mg. into foetal Merino lambs. Two lambs which received an injection at 79 and 120 days respectively aborted within a week after the operation. Gestation periods of surviving lambs in other ewes seemed to be increased by an injection before the 110th day, but shortened by an injection after the 120th day. We obtained similar results in experiments designed to investigate the effects of cortisone acetate on the ability of newborn Scottish Blackface lambs to absorb colostral proteins. Laparotomies were performed on five ewes and 50 mg. of cortisone acetate (Cortistab injection, Boots Ltd.) were injected i.m. into a hind leg of one foetus in each ewe, through the foetal membranes. All ten lambs carried by the ewes were born alive about a week after the operations. Identification of the experimental lambs was difficult. Of the lambs tentatively