| Abstract: | Ovarian function was evaluated in mature female llamas (n = 2) during seven ovulations in 2 conceptive and 5 nonconceptive ovarian cycles by measuring urinary and plasma hormone concentrations. Ovulation was induced by three different methods; administration of gonadotropin-releasing hormone (GnRH), copulation with a vasectomized male and copulation with an intact male. Plasma estradiol and progesterone concentrations, and urinary concentrations of estrogen conjugates and two progesterone metabolites, pregnanediol-3-glucuronide (PdG), and immunoreactive (iPdG), concentrations were compared to determine their value in monitoring ovarian function. Estrogen concentrations in urine corresponded to estradiol levels in plasma and accurately reflected changes in follicular activity when evaluated over several daily samples. Plasma progesterone and urinary iPdG were reliable indicators of luteal function. These data represent the first comparison of blood and urinary hormone measurements for monitoring the complete ovarian cycle of an ungulate, and demonstrates that either can be used to assess changes in ovarian activity in this species. |
