Faecal steroid metabolites assay as a non-invasive monitoring of reproductive status in animals

Measurement of faecal steroids as a non-invasive technique is widely used to monitor reproductive hormones in captive and free-ranging wild animals. This method offers a great advantage over invasive techniques like blood collection and deserves to be used in domestic animals. Repeated blood sampling is stressful, having animal welfare issues, difficult to obtain in field condition. In the faeces of cow, estradiol 17-α predominated, whereas in mares and sows, estradiol 17-β and estrone are main estrogens. Steroids are metabolized in liver, excreted in faeces and extraction is done by using a variety of methods such as ethanol, methanol etc. Faecal estrogen and progesterone metabolites evaluations are wel1 established approaches for monitoring of reproductive functions in a variety of mammalian species. So in future this method may be the most suitable for monitoring of reproductive status in farm animals particularly under field conditions.