p-cresol and oleic acid as reliable biomarkers of estrus: evidence from synchronized Murrah buffaloes

Successful reproductive management in buffaloes depends on effective estrus detection. Urinary pheromones identified from natural estrous cycle have been reported to decipher estrus phase. However, its presence has not been analyzed in the urine after synchronization. Thus, our present investigation was to investigate the influence of synchronized estrus urine in bulls and to examine the presence of estrus-specific compounds ascertained in natural estrus in synchronized buffaloes. Mid-stream urine was collected from six synchronized buffaloes during various phases of estrous cycle and volatiles were examined using GC-MS. Sexual provocation in bulls was established by displaying persistent flehmen and frequent mounting towards estrus urine from synchronized animals. Totally forty-two volatile compounds were identified from three phases of estrous cycle, more specifically 4-methyl phenol (p-cresol) and 9-octadecenoic acid (oleic acid) in estrus urine of synchronized animal as similar to natural estrus. Hence, these chemical cues in buffalo urine might be employed as potential marker candidates for the development of an estrus detection aid.