The aims of the present study were to determine presence of immunoreactive progestins in feces, correlate fecal progestins with plasma progesterone (P₄) concentrations and subsequently assess the role of fecal progestins in monitoring estrous cycle in Kedah Kelantan (KK) beef cows. A total of 12 cycling cows were subjected to blood and matched fecal sampling twice a week for 9 weeks. The concentrations of plasma P₄ and fecal progestins extracted using a modified technique, were determined by a P₄ radioimmunoassay (RIA) kit. There was a significant positive correlation between the concentrations of fecal progestins and plasma P₄ (r = 0.6, P<0.01), as tested for the whole group except one animal. High performance liquid chromatographic separation of fecal extracts and subsequent radioimmunoassay revealed presence of four immunoreactive progestins against the P₄ antibody. These results imply that the non-invasive measure of fecal progestins using a DSL-3900 RIA kit can be used to monitor the ovarian activity of beef cows.

Key words: Feces, KK cows, Ovarian cycle, Progesterone, Progestin, Plasma