Reproductive studies of the Oryx

The genus Oryx comprises one species already extinct in the wild and others that are rapidly disappearing. It is important to understand the reproductive physiology of these species in order to ensure their successful captive propagation. It was determined behaviorally and hormonally that the scimitar‐horned oryx's 21–22 d estrous cycle very closely resembled that of the domestic cow. Four females of three species (Arabian, scimitar‐horned, and fringe‐eared oryx) were treated with prostaglandin (PG) and pregnant mares serum gonadotropin (PMSG) or follicle‐stimulating hormone (FSH). All animals responded to prostaglandin treatment with shortened cycles and behavioral estrus. Ovulation occurred in all females but only one responded to gonadotrophin treatment with a mild superovulation. An embryo recovered from an Arabian oryx was frozen in liquid nitrogen for 6 months. Upon thawing, the normal‐appearing morula was surgically transferred to a scimitar‐horned oryx. The recipient failed to carry the embryo and returned to estrus within three weeks of the transfer. It was demonstrated that induction of ovulation and synchronization of estrus can be achieved in the three Oryx species with PMSG or FSH combined with prostaglandin treatment.