Time-dose relationships of PMSG and map-intravaginal sponges and its effect on embryonic mortality in Karakul ewe

Abstract

Different dosage levels of pregnant mare serum gonadotrophin (PMSG) were applied in conjunction with medroxyprogesterone acetate impregnated intravaginal sponges at different times in relation to sponge removal the object of the study was to find the most economical dose level and the correct time of application which would result in the least variability as far as ovarian response and embryonic failure was concerned. The lower dosage levels of PMSG (300 I.U.) injected intramuscularly, two days prior to sponge removal for out of season and on removal for the breeding season treatments, gave the most consistent ovulatory response as well as the lowest incidence of wastage of ova. Losses due to fertilization failure and embryonic death were more or less equally proporttoned within the overall loss of potential ova of 50%and 53,7% recorded respectively for out of season and breeding season treatments.