Effects of PMSG and the prostaglandin F-2 analogue, cloprostenol, on superovulation, fertilization and egg transport in the ewe

Abstract

Romney ewes were artificially inseminated at estrus after treatment with PMSG [pregnant mare serum gonadotropin] on day 12 of the cycle, cloprostenol on day 14, or both. PMSG resulted in increased ovulation numbers and large follicles but cloprostenol had no effect alone or with PMSG. PMSG and closprostenol alone led to reduced proportions of eggs fertilized and PMSG also reduced the proportion of ewes with fertilized eggs. Egg distribution in the reproductive tract indicated more rapid egg transport in ewes treated with PMSG. A greater proportion of eggs was recovered from the uterus in ewes in which estrus was first detected at night. Cloprostenol, as administered to PMSG-treated ewes in this trial, offered no advantage for the preparation of donor ewes for egg transfer.