Association of faecal volatiles and steroids with behavioural expression during oestrous cycle of sheep (Ovis aries).

This study was investigated to determine the faecal volatiles, steroid hormones and their correlation with behavioural signs during oestrous cycle in sheep (Ovis aries). This experiment was monitored from pro-oestrous to met-oestrous phases for correlation of endocrine dependence biochemical constituents in faeces and blood to detection of oestrous biomarkers. Medroxyprogesterone acetate sponges were used for 8 days to bring uniformity of oestrus in sheep. Faeces were collected during different phases of cycle and subjected to determination of fatty acids, minerals, oestrogens and progesterone analysis. Likewise, blood samples were also obtained for enzymatic and no-enzymatic antioxidants. The results revealed that faecal progesterone and oestrogen levels significantly increased during pro-oestrous and oestrous phase, respectively (p < .05). The blood plasma enzymatic levels showed significant demarcation during the oestrous phase than other periods (p < .05). There were also reported marked variations in volatile fatty acids across different phases of the oestrous cycle. Interestingly, methyl octanoate, methyl cis-10 pentadecenoate and methyl heptadecanoate volatiles were found to be specific to oestrus period. In addition, methyl hexanoate, methyl palmitoleate and methyl cis-9 oleate were identified in met-oestrus, indicating their possible role to be an oestrous biomarker. It is concluded that the pattern of volatile compounds and faecal steroids, in association with behavioural patterns, could be measured as a non-invasive method of heat detection in sheep.