Communications of the ACM
Cattle Rangers Trade the Open Range For Virtual Fencing
Credit: Laramie River Ranch
The world of electronic conveniences has reached the cow pasture. In the not-so-distant future, landscapes may be dotted only with virtual fences and cattle will be herded with global positioning system (GPS) technology. As with most electronics, battery life is an issue. In this case, the amount of battery power a bovine can carry on the collar around its neck limits the use of the technology.
This future is brought closer by a study published in the May 2011 issue (Vol. 64, No. 3) of Rangeland Ecology & Management, a peer-reviewed journal of the Society for Range Management. As described in "Automated Animal Control: Can Discontinuous Monitoring and Aversive Stimulation Modify Cattle Grazing Behavior?," the study employed GPS and automated animal control (AAC) systems as an alternative to physical fences. The study tested a discontinuous use of AAC — the devices were activated only 25% of the time — to reduce power consumption.
The goal of this project was to modify grazing behaviors of cattle. Livestock and rangeland management includes ensuring a stocking rate that the land can support, protecting areas from overgrazing, and targeting grazing to reduce fuel that can create wildfires. This is usually accomplished with physical fencing.
The study, conducted in Queensland, Australia, tested the effectiveness of virtual fencing on four groups of Brahman steers. Each steer was fitted with a collar containing a GPS receiver, a sensory stimulus device that created a buzzing sound, and another stimulus device that produced a 1-second electrical pulse.
Each group of cattle was placed in a paddock that featured a supplemental feeder at one end. At first, the animals were given unlimited access to the entire enclosure. Then a restricted zone around the desirable food source was delimited and discontinuous AAC — a 5-minute usage of stimuli followed by a random 0-30-minute interval of no stimuli — was applied to control the cattle's behavior. It was expected that through negative reinforcement the animals would progressively learn to avoid the area.
Overall, the study showed a 97% reduction in the use of the restricted zone by the cattle. This finding provides evidence that discontinuous use of AAC is sufficient to effectively modify the grazing behavior of cattle. The success of the discontinuous method of reinforcement will help to overcome energy supply limitations and make AAC applications for cattle a commercially viable option.
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