The administration of hCG or GnRH induce the formation of accessory corpora lutea

Abstract

The aim of this study was to evaluate the effect of the administration of hCG or GnRH at day 4 post fixed-time artificial insemination (FTAI) on the formation of accessory corpora lutea (acc-CL) and the concentration of serum progesterone (P4) in sheep. Multiparous adult Merino ewes (n=36) were treated for estrus synchronization using two intramuscular (i.m.) injections of prostaglandins (PG, 125 μg Cloprostenol, Cyclase®, Syntex, Argentine) with an interval of 14 days. At 53-56 h after the second PG application, FTAI was performed vaginally with a dose of 100 million spermatozoa of fresh semen.