| Abstract: | In Rajasthan, India megastrol acetate and progesterone were administered to ewes (25 Chokla, 25 Malpura, aged between 3 and 4) in November 1968. Each ewe received 50 mg of either megastrol acetate or progesterone. Administration was intravaginal or intramuscular. During treatment only 3 ewes (2 megastrol acetate-injected and 1 progesterone-injected ewes) came into heat; thus, the progestogens exerted an inhibiting effect. 76% and 88% of the megastrol acetate and progesterone ewes, respectively, exhibited heat within 96 hours of therapy's end. Breed showed no significant effect on occurrence of estrus after therapy. Release of estrus within 96 hours occurred in 91.3% and 74.0% of intravaginally and intramuscularly treated ewes, respectively. 17 (41.5%) of the 41 ewes inseminated at their synchronized estrus lambed as a result of breeding in that first cycle. Thus, questions arise as to efficiency of ovulation, fertilization, nidation, and lambing in the case of synchronized estrus by use of different progestogens. 75% of ewes showing typical fern pattern at insemination lambed. An antiseptic vaginal douche applied after withdrawal of the sponge used in iv administration might be responsible for increased posttreatment fertility in this group. |
