Association of fecal volatiles and steroids with behavioral expression during estrous cycle of sheep (Ovis aries).

This study was investigated to determine the fecal volaties, steroid hormones and their correlation with behavioral signs during estrous cycle in sheep (Ovis aries). This experiment was monitored from pro-estrus to met-estrus phases for correlation of endocrine dependence biochemical constituents in feces and blood to detection of estrous biomarkers. Medroxyprogesterone acetate sponges were used for eight days to bring uniformity of estrous in sheep. Feces were collected during different phases of cycle and subjected to determination of fatty acids, minerals, estrogens and progesterone analysis. Likewise, blood samples were also obtained for enzymatic and no-enzymatic antioxidants. The results revealed that fecal progesterone and estrogen levels significantly increased during pro-estrus and estrus respectively (P < 0.05). The blood plasma enzymatic levels showed significant demarcation during the estrous phase than other peroids (P < 0.05). There were also reported marked variations in volatile fatty acids across different phases of the estrous cycle. Interestingly, methyl octanoate, methyl cis-10 pentadecenoate and methyl heptadecanoate volatiles were found to be specific to estrus period. In addition, methyl hexanoate, methyl palmitoleate and methyl cis-9 oleate were identified in met-estrus, indicating their possible role to be a estrous biomarker. It is concluded that the pattern of volatile compounds and fecal steroids, in association with behavioral patterns, could be measured as a non-invasive method of heat detection in sheep.