Comparative aspects of steroid hormone metabolism and ovarian activity in felids, measured noninvasively in feces

This study validated and applied fecal steroid hormone assays to track ovarian activity in multiple felid species without restraint or blood sampling. The authors characterized how estrogen and progestin metabolites are excreted in feces and used these measures to follow estrous cycles, ovulation, and luteal phases across domestic and nondomestic cats. The approach revealed species differences in cycle length, the occurrence of spontaneous and induced ovulation, and the hormonal signature of pseudopregnancy. By establishing a noninvasive monitoring toolkit, the work transformed how zoos assess reproductive status, time artificial insemination, and diagnose ovarian dysfunction. It became a methodological cornerstone for felid conservation endocrinology and underpins many later breeding-management studies.