Abstract
Virtual fencing contains and controls grazing cattle using sensory cues rather than physical fences. The technology comprises a neckband-mounted device that delivers an audio cue when the animal nears a virtual boundary that has been set via global positioning system, followed by an electrical stimulus if it walks beyond the boundary. Virtual fencing has successfully been used to intensively graze cattle using a simple virtual front-fence, but a more complex intensive grazing system comprising moving virtual front and back-fences has not been assessed. We studied the effectiveness of virtual fencing technology to contain groups of Angus heifers within grazing cells defined by semi-permanent electric side-fences and virtual front and back-fences, compared to groups of heifers contained in cells defined only by electric fencing. Four groups of 10 Angus heifers were randomly allocated to a “control” (grazed with a conventional electric front and back-fence, n = 2 groups) or “virtual fence” treatment (grazed with a virtual front and back-fence, n = 2 groups). The groups of heifers grazed four adjacent experimental paddocks that were established using TechnoGrazing™ infrastructure. An estimated 9.5 kg pasture DM/heifer.day was offered in each of three 3 day allocations (9 day study period). Data collected include cues delivered by the neckbands, time beyond the virtual boundaries, pasture consumption for each allocation and heifer live weight changes over the study period. The virtual front and back-fences successfully contained one group of heifers in their grazing cell, but the second group of heifers spent an increasing amount of time in the exclusion zone during the second and third allocations and consequently received an increasing number of audio and electrical stimuli. There were no effects of electric or virtual-fence treatment on live weight change or pasture utilization. By grazing heifers in adjacent paddocks our experimental design may have produced a motivation for some heifers to cross the virtual boundary to regain close contact with familiar conspecifics. Despite this, valuable learnings were gained from this study. Most notably, virtual fencing should not be used to manage cattle that have close visual contact to other mobs. We conclude that the successful application of virtual fencing technology needs to accommodate the natural behaviors of cattle.
Highlights
Virtual fencing is an emerging technology that contains and controls grazing cattle using sensory cues rather than physical fences
All but one heifer interacted with the virtual fence in this time, during which animals took an average (±sd) of 1.2 ± 0.6 interactions with the virtual fence to respond to the audio cue alone
This means that most animals responded appropriately to their first audio cue despite it never having been paired with an electrical pulse
Summary
Virtual fencing is an emerging technology that contains and controls grazing cattle using sensory cues rather than physical fences. An electrical stimulus is delivered by the device if, following the audio cue, the animal walks beyond the virtual boundary, but not if it stops walking or turns back. This type of training is termed positive punishment and is the same as that used to train cattle to electric fences. In both cases, administration of the aversive electrical stimulus following the undesired behavior (i.e., physical interaction with the electric fence or progressing beyond the virtual boundary after an audio cue) results in the behavior becoming less likely in the future. Virtual fencing affords a flexibility to grazing management that has the potential to revolutionize pastoral livestock production
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