Scientists create a mechanical ‘bull's nose’ Researchers have successfully developed a novel and easy-to-use instrument to detect oestrus (sexual readiness) in dairy cows. The aim was to enable optimal timing of artificial insemination. Health © Thinkstock In nature, successful conception in cattle is dependent on the timing of insemination, which relies on detection of the cow's sex pheromones by the bull. But, as dairy farmers often rely on artificial insemination (AI) to maximise milk and offspring production in cattle, they can get the timing wrong. An EU-funded project called ‘Pheromone-based sensor system for detecting estrus in dairy cows’ (BOVINOSE) aimed at developing a tool that essentially acts as a bull's nose and thus successfully detects oestrus in cows. The project brought together individuals with expertise in pheromone research, sensor development and signal processing, and veterinary know-how. Research into the so-called volatile info-chemicals, which are components of the sex pheromones, revealed that faeces were the most suitable source of the pheromones. Specifically, researchers identified acetic and propionic acids as effective indicators of oestrus and found that they increased in amount at approximately 24 hours before ovulation. Prior to developing a functional prototype of the whole system, researchers investigated a set of sensors for detecting the pheromones. The team then assembled a final sensor array from eight metal oxide gas sensors, which were calibrated using acetic and propionic acids. The functional prototype consists of a probe, the array of sensors, and software for control and end-user interaction. Laboratory and field tests resulted in the construction of a second version of the device, which is smaller, portable, more integrated and automatic. Researchers found that the device provides a 70 % oestrus detection rate. An economic assessment of the device also revealed a great benefit in terms of annual returns to both the customer and the device manufacturer. The tool can potentially be applied in various other forestry and agriculture settings for rapid, sensitive and reliable detection of volatile chemical markers.
