Characterization of the estrous cycle and reproductive traits of the aoudad (Ammotragus lervia) in captivity

Abstract

In this study the estrous cycle of the aoudad has been analyzed and characterized for the first time, using non-invasive methods for tracking reproductive cyclicity. The duration of the estrous cycle is 23 days (range 16-32 days), with a luteal phase of 17 days (range 12-27 days) and an interluteal phase of 6 days (range 3-14 days). The estrous cycle did not differ between females, but it was affected by the time of the year. Intraindividual variation of the cycle was observed in one out of the nine individuals. The average hormone concentration values, the estrogen:progestogen ratio, as well as their minimum and maximum values for each interluteal and luteal phases of the estrous cycle, are shown. Interindividual differences found in these values were basically associated with age. Females tended to start their cycle when in the presence of an adult male. Anestrus was observed in study females except for the oldest (14 years old). Age and anestrus onset were correlated, with younger females starting earlier than the older ones. This study reveals that Ammotragus reproductive biology is more similar to that of Capra than Ovis, except for some endocrinological features.