Faculty of Veterinary Science
Department of Veterinary Anatomy and Physiology
Selected Highlights from Research Findings
In many animals odourless chemicals called pheromones communicate an individual's identity and state of sexual readiness. The chemical message is received by pheromone receptors that have only been found in a special organ called the vomeronasal organ (VNO) which consists of paired blind-ending tubes on either side of the nasal septum. In contrast to the olfactory receptors, which pick up odours and do not connect to the hypothalamus, these receptors are linked to the hypothalamus. In goats, when a ram or buck is introduced to a group of females, their reproductive cycles tend to synchronize and they may even express oestrus and ovulate during the non-breeding season – a phenomenon known as the 'buck effect'. In order to investigate the role of the VNO in this process the organ was rendered non-functional by cauterization of the nasopalantine canal in half of a group of does before the introduction of bucks, and sexual activity measured in both groups in terms of sexual behaviour, by measuring estradiol concentrations in the blood and by determining conception rates. While 56% of does with functional VNOs became pregnant, only 20% of those without it conceived. Lower oestradiol values were also found in treated does, indicating that the VNO plays an important role in mediating the 'buck effect' through the reception of male pheromone signals. Further work is in progress to determine the importance of the VNO for neonatal offspring recognition in goats.
Contact person: Prof KK Booth.
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