Longitudinal Analysis of Reproductive and Adrenal Hormones in Bontebok (Damaliscus pygargus pygargus)

The bontebok (Damaliscus pygargus pygargus) is one of conservation’s most promising success stories, yet its reproductive and adrenal physiology has not been described, limiting evidence-based care of animals held under human management. We validated enzyme immunoassays for fecal progestagen, testosterone, and glucocorticoid metabolites and applied them to a longitudinal data set from six zoo-housed bontebok (three males, three females) sampled two to three times weekly over more than seven years. Assays were biochemically and biologically validated, with glucocorticoid metabolites rising markedly within 24 h of translocations and veterinary procedures. Progestagen monitoring characterized estrous cycles as 21 to 25 days and four pregnancies with a range of 223 to 236 days. Reproductive activity in this Northern Hemisphere population was displaced roughly six months relative to wild Southern Hemisphere populations. Males showed peak testosterone metabolites from June to October, and females cycled from September to January, implicating photoperiod as the possible driver of seasonality. Both sexes displayed seasonal glucocorticoid peaks in late spring and early summer despite constant nutrition, water, and social conditions. These findings provide the first endocrine reference base for the bontebok, are consistent with the theory that this subspecies is seasonally polyestrous with spontaneous ovulation, and support improved welfare monitoring and reproductive management.