Virtual Fence
In Arizona and other western states, ranchers and land managers rely on thousands of miles of permanent wire fencing to manage livestock on extensive rangelands (Hayter 1939; Netz 2004). This type of fencing has improved rangeland conditions in many places by aiding in the application of grazing systems (Holecheck et al. 2011). However, wire fencing can fragment landscape connectivity, pose a risk to wildlife, and is a major financial investment. Moreover, it offers limited flexibility in adjusting pasture size, actively manipulating grazing distribution, or avoiding high-use areas or sensitive habitats within a pasture (Jakes et al. 2018). As a result, there are constraints on the use of permanent fences as a tool for managing riparian health, post-fire vegetation recovery, or improving livestock distribution. Virtual fencing is an emerging precision livestock management technology used to address these limitations and increase management flexibility and adaptive capacity to respond to changing environmental conditions as part of a larger grazing management system (di Virgilio et al. 2018; Lima et al. 2018; Trotter 2010). As a management tool, a virtual fence (VF) system uses invisible barriers, established by Global Positioning System (GPS) coordinates, that influence livestock movement with a combination of auditory and electrical cues (Ehlert et al. 2024; Antaya et al. 2024). Primary elements are shown in Figure 1 and include: (1) a software interface to draw virtual fence lines and the boundary zone on a digital map, which defines the grazing area and exclusion zone; (2) a GPS-enabled collar fitted around the circumference of an animal’s neck or other wearable device that contains technology to track livestock movement and deliver auditory and electrical cues to influence livestock distribution; and (3) base stations and/or cellular towers to transmit and receive communication between the software and collars (for more information please see Rangelands Gateway:https://rangelandsgateway.org/virtual-fence). A VFsystem relies on livestock successfully recognizing anassociation between two cues – an auditory cue (beepingsound) and an electrical cue (electrical pulse) – originating from the GPS enabled collars when the animal enters a boundary zone. Recognition of these cues is learned
through training with classical conditioning and negative reinforcement. After training, livestock should respond to the auditory cue by changing direction away from the exclusion zone (Figure 1). If the association between cues is continuous, predictable, and controllable, a collar can influence livestock movement. Understanding how livestock recognize and interpret this association can limit potential risks for animal health and welfare. This factsheet provides an overview of the underlying learning methods (i.e., classical conditioning and negative reinforcement) used to train livestock.