Endocrine correlates of female reproductive activity in the roan antelope (Hippotragus equinus)

Abstract

AbstractAlthough ovarian endocrine activity has been described in most members of the tribe Hippotragini, little is known about the reproductive endocrine correlates of the roan antelope (Hippotragus equinus), an endangered antelope species of southern Africa. This study characterised the endocrine pattern of the reproductive activity (oestrous cycle, pregnancy and post‐partum period) in the female roan antelope by monitoring faecal progestogen metabolite (fPM) concentrations and oestrogen metabolite (fEM) concentrations for cyclicity and observing reproductive behaviours. The study was carried out over the course of 12 months. At the beginning of this study, all 18 focal females (nulliparous, primiparous and multiparous) were monitored for cyclicity (for between 3 and 4 months). Following observed copulation, pregnancy in multiparous females (n = 10) was subsequently monitored until parturition and 21 days post‐partum. Individual faecal samples were collected three times per week during the presumed period of cyclicity, twice per week during pregnancy and daily for 21 days post‐partum. Mating births, courtship events, and copulations were recorded when observed. In eight of the 18 females monitored, the patterns of fPM and fEM concentrations indicated oestrous cycle lengths (n = 10) of approximately 30.8 ± 2.1 days. The determined lengths of luteal and follicular phases were approximately 15.8 ± 1.5 days and 14.6 ± 2.1 respectively. Pregnancy was marked by a pronounced increase in fPM concentrations until parturition, and lasted approximately 280.4 ± 4.8 days; whereas the intercalving period ranged between 306 and 380 days (n = 9; mean: 333.2 ± 7.4 days). Twenty‐one day after parturition, 78% of the focal females (n = 5) did not show a resumption of the ovarian activity. This study demonstrated that monitoring faecal reproductive hormone metabolite patterns is a valuable approach for estimating ovarian activity in roan antelope and may be used to assist respective conservation breeding programmes by improving management practices.