An investigation of early prenatal loss in a commercial sheep flock

Abstract

The extent of prenatal losses of ova was studied in one hundred 5½-year-old Peppin Merino ewes mated with two rams for five weeks in November-December. Of a potential of 157 ova, the minimum losses due to ewes mating but losing all ova, and to ewes losing one ovum out of two or three shed, were 9.5 and 12.7%, respectively.There was a significant effect of pre-joining liveweight on ovulation rate, and evidence of a difference between sires in the proportion of ova lost by ewes with multiple ovulations.