Induction of Ovulation in Seasonally Anovular Ewes by the Introduction of Rams: Effects of Progesterone and Active Immunization Against Androstenedione

Abstract

The effects of progesterone priming and active immunization against androstenedione on ovulation, oestrus and premature luteal regression were observed in seasonally an ovular Merino ewes which had been induced to ovulate by the introduction of rams, Ovulation was induced in 27 out of 36 ewes, and the response was not affected by either immunization or progesterone priming, The ovulation rate (mean number of ovulations per ewe ovulating) was higher in ewes immune to androstenedione, but there was no significant effect of this treatment on oestrus or luteal maintenance