Does Virtual Fencing Work for Grazing Dairy Cattle?

Simple Summary Fences are used to prevent the over and under grazing of forages by herbivores. These fences can either be permanent, temporary or virtual. Virtual fencing uses collar-mounted GPS devices to contain animals within an area. The collars emit an audio tone as the animal approaches the virtual fence line. If the animal continues forward, an electrical pulse is applied. However, if the animal stops or turns around, they do not receive a pulse. We evaluated the application of virtual fencing for grazing dairy cows, to gain an understanding of how individuals learn virtual fence simuli. The virtual fence contained cattle within predetermined areas for most of the time (99%). However, there was significant variation between individuals for the number and type of interactions with the virtual fence, and animal location within the paddock varied. The success of maintaining animals within a grazing area may have costs for both individual animal welfare and efficient pasture utilization. Pasture management in Australia's dairy industry requires the manual shifiting of temporary electric fences to maintain pasture quality and growth. Virtual fencing presents an alternative to save time and labour costs. We used automated virtual fence (VF) collars to determine the variation in learning of the virtual fence stimuli, and evaluated the success of the technology to contain cows in a predetermined area of pasture. Twelve Holstein-Friesian non-lactating multiparous dairy cows were fitted with the collars, and a VF was used to restrict cows to two grazing allocations (G1 and G2) across six days. Cows received an audio tone (AT) when they approached the virtual fence, and a paired electrical pulse (EP) if they continued forward. The VF contained cows within predetermined areas for 99% of time, but cows spent the least time near the fence (p < 0.01). The number of stimuli reduced through time, demonstrating the ability of cows to learn the VF (p = 0.01). However, the mean number of EP per day ranged from 1 to 6.5 between individuals (p < 0.01). Therefore, successful containment may have a welfare cost for some individuals. Further work should focus on this individual variation, including measures of welfare.