Detection of Male Olfactory Information by Female Goats: A Calcium Imaging Approach

In mammals, reproductive function can be modulated by sociosexual factors. In small ruminants such as goats, phenomena such as puberty acceleration and the “male effect” have been hypothesized to depend on male olfactory information, but the source of these odorants and how they are detected is currently unclear. Calcium (Ca2+) imaging is a widely developed approach in rodents to assess the activity of olfactory sensory neurons (OSNs) and vomeronasal neurons (VSNs), originating from the main olfactory epithelium (MOE) and the vomeronasal organ (VNO), respectively. Our study aimed to adapt this approach to primary cultures of dissociated goat OSNs and VSNs. MOE and VNO cells were stimulated with urine and fur extracts from castrated or sexually active bucks. Ca2+ responses were observed in cells from the two olfactory systems for each stimuli. These results indi- cate that (1) both MOE and VNO are involved in male chemosignal detection by females during the breeding season, and (2) VSNs and OSNs from ovulatory goats are activated by male olfactory information, independently of male sexual activity. The development of this approach will be of high interest in the search for potential chemosignals involved in the regulation of sociosexual behavior in goats and associ- ated physiological regulations.