Virtual fencing systems: balancing production and welfare outcomes

There is rapid growth in precision livestock farming technologies for grazing livestock (Aquilani et al, 2022). Most wearable sensor systems are passive, providing data to livestock managers, with diagnostics for health, nutritional or reproductive states or events such as oestrus and calving. Animal location is often an important element of outdoor systems with Geographical Navigation Satellite Systems (GNSS, often referred to as GPS) creating map-based visualisations (Herlin et al, 2021).

Virtual fencing (VF) or virtual herding (VH) systems are a step up from passive sensors with active livestock management and precision livestock farming technology. VF systems use two-way digital communication between livestock managers and each animal via its wearable device. Stock managers can then actively, but remotely, manage boundaries for the herd, opening up or restricting movement in near real-time. One current commercial system goes a step further with signals prompting directional movement, to automate moves to and from pasture to milking parlour. Increasing quality of data and automation creates opportunities to reduce farm hardware such as fences and gates, reduce labour for moving stock and increase efficiencies around surveillance of livestock. However, there are undoubted welfare costs and risks to animals, leading to opposition by some commentators, e.g. RSPCA (2022), because they give electric shocks for crossing the virtual fence line.