Assessment of pregnancy in Kiang mares (Equus hemionus holdereri ) using estrogen determination in feces.

Analysis of fecal estrogens was used to diagnose pregnancy in 6 Kiang mares (Equus hemionus holdereri ) that were kept at Tierpark Berlin. Three extraction methods were compared and were followed by an established RIA for total estrogen. Extraction of desiccated feces with chloroform/n-hexane and KOH, with and without enzyme hydrolysis showed better results than extraction with diethylether without hydrolysis. Pregnancy was confirmed by observation of foaling in 2 mares that showed estrogen concentrations between 800 and 1800 ng/g and in 1 mare that showed widely fluctuating values between 500 and 1300 ng/g of feces. Two mares with estrogen concentrations below 500 ng/g were not seen to foal. The method using chloroform/n-hexane and KOH without enzyme hydrolysis seems practical for non-invasive evaluation of the endocrine status in this endangered Equidae species.