Detecting Heat Stress in Dairy Cattle Using Neck-Mounted Activity Collars

Collar-based activity sensors are in common use as a means of detecting oestrus to optimise farm fertility and, hence, productivity. Recently, the same acceleration-derived signals have been processed to detect the time spent ruminating and eating, which, together, give an insight into animal welfare. Here, the use of neck-mounted accelerometers to provide a quantifiable measure of the time period that an individual animal exhibits signs of heat stress is reported. Heat stress has a significant impact on both animal welfare and productivity. Cattle studied during elevated temperatures were found to exhibit signs of exaggerated breathing motions, an indicator of heat stress, for 8 h on average per day, exceeding the time that cattle spend feeding and is similar to daily rumination times. No similar cases were recorded in the cooler conditions of a Scottish winter. The approach offers a cost-effective measure of heat stress and a potential tool to quantify its impact more generally.