Containment

Each company’s VF system contain livestock differently, but they all function in a similar way. When an animal approaches the VF boundary, the collar enters an active mode and begins tracking the animal’s location more frequently. If the animal crosses the boundary, the collar first delivers an audio warning, allowing enough time for the animal to turn back into the designated area. If the animal doesn't respond, the collar will then emit a mild electric pulse through the chain around its neck. In some systems, the pulse is triggered based on the amount of time the animal has spent near the boundary, while in others, it’s triggered by crossing an additional outer boundary. If both the audio and pulse cues fail and the animal continues moving beyond the VF, the collar will eventually deactivate.

Over time, it does seem that the livestock learn to respond to the audio warnings alone, with less need for the pulse warnings. For example, a recent trial utilized 37 cattle with no previous exposure to virtual fencing to create fuel breaks while wearing Gallagher eShepherd collars. During the initial training period, the cattle required an electrical pulse 24% of the time to be contained, but this decreased to 4% by the end of the trial a month later.

It’s important to understand that VF boundaries function like a one-way gate. The collars use audio and electric pulses to keep livestock within the designated area, but they can enter the VF zone freely without receiving any warnings or corrections. This feature is useful when escaped animals want to rejoin the herd inside the VF or when moving livestock into a new area where the VF is already active.

While VF systems are designed to contain livestock without physical fencing, the containment isn’t perfect. As such, a VF system should be used with a sturdy perimeter fence. In our experience, the VF system contains livestock around 80 to 99% of the time, but this is influenced by many factors. In addition to the size and shape of a VF, several competing factors can influence how effectively livestock are contained within the designated area. These factors include the rest of the herd's location (including any livestock without VF collars), the quality and amount of feed, access to water and shade, the presence of predators, the location of calves, reproductive cycles, feed attractants like salt and protein, and even inclement weather. In general, the more these factors are controlled or mitigated to encourage animals to remain within the virtual boundary, the more successful the VF will be at containing the livestock.