Analysis of ovarian and adrenal activity in Namibian cheetahs

Captive breeding of cheetahs (Acinonyx jubatus) has had limited success because a high percentage of captive females exhibit a lack of ovarian activity. This study examined concentrations of ovarian and adrenal hormones in wild-caught cheetahs (n = 3) housed in large outdoor enclosures on private game ranches in Namibia. Cheetahs were monitored for a 16-month period to investigate the effect of season on ovarian and adrenal function. Secretory profiles of oestradiol, progestagen, and cortisol metabolites were quantified non-invasively using faecal steroid analysis. All three cheetahs exhibited ovarian activity; however, none cycled continuously. Periods of anoestrus occurred during overlapping periods between August and December 1994, but not during the same time period in 1995. Mean duration of the oestrous cycle, oestrus period and baseline concentrations of reproductive hormones were consistent with those observed in other captive cheetah populations. Concentrations of faecal corticoids were lower than those from captive cheetahs in North America. There was no correlation between adrenal activity and ovarian function. Spontaneous ovulation was documented in one cheetah. These findings support those of earlier studies that even under natural and, therefore, presumably ideal environmental conditions, reproductive activity in captive cheetahs is not continuous.