A recent study from Oklahoma State University shows that compared to physical fence boundaries on cattle range land, virtual fences can lead to greater vegetation variety, which would benefit grassland birds and pollinators. (Courtesy of Oklahoma State University)
Barbed wire, wooden planks, electric wire—for centuries, ranchers have used various fencing materials to constrain cattle into a specific grazing area.
But for some, this time-honored practice needs a 21st century update. Fencing requires upkeep and management to corral animals safely and efficiently, which can be time consuming for ranchers. Cattle can sustain injuries from broken or loose wire and boards. Physical boundaries also impact the land itself since cattle graze right up to a fence line, creating sharp differences between grazed pasture and the vegetation on the other side of the fence.
A recent study from Oklahoma State University shows that compared to physical fence boundaries on cattle range land, virtual fences can lead to greater vegetation variety, which would benefit grassland birds and pollinators. (Courtesy of Oklahoma State University)
New research from Oklahoma State University, presented in December at the 2024 annual meeting of the American Geophysicists Union, examines the benefits for pollinators, birds and native grasslands when ranchers adopt virtual fencing technology instead of relying on traditional materials. The future of fencing might be remote-controlled, invisible and safer for birds and pollinators—helping protect biodiversity and reduce damage on grassland ecosystems.
Tim Olsen, a graduate research assistant at Oklahoma State University’s department of Natural Resource Ecology and Management is one of the authors of the new study. This virtual fencing project checked off a lot of boxes for his grad school interests, especially getting to use GIS—the graphic information system that uses an algorithm based on GPS and other data to determine an animal’s location—and drones to conduct ecological research. “I hadn’t really ever heard of virtual fencing before. I was just kind of interested to see what it would be about,” says Olsen, whose main research interest is using remote sensing and geographic information systems for natural resource management.
The authors of the study used this drone to monitor the effects of virtual fence boundaries on the structure and health of grassland vegetation. (Bryan Murray)
Virtual fencing for cattle employs different technology than the invisible fences used to contain wandering dogs inside their yards. That technology relies on a buried underground wire that sends electric shocks to a dog’s collar when it crosses the boundary. In virtual fencing, the boundaries are controlled by GPS. Pasture is divided into three zones—the grazing zone, an auditory boundary zone, and an exclusion zone. Cattle wear GPS-controlled collars and receive increasing sound and electrical warnings when they cross from the grazing zone into the auditory boundary zone. The electric jolts are around 800 watts, similar to the shock from a hot wire fence. Ranchers can change the coordinates of their pastures with ease, making for an efficient way to swap out one grazing area for the next.
“Livestock keep further away from virtual fences than they do from physical fences. Oftentimes, with a physical fence, they’ll go right up to that boundary which they can see and know is there for sure,” says Olsen. “With virtual fencing, it’s a little bit more complicated because they can’t see the boundary. And then there’s a buffer zone where auditory alarms go off.”
Screenshot of the virtual fence boundaries used by the study’s authors. (Tim Olsen)
For the study, Olsen and colleagues wanted to compare the vegetation structure, or the density and height of plants, along both virtual and physical fencelines to determine what value virtual fencing might provide to protecting certain habitats. They set up six 50-meter by 20-meter paddocks, with 50-meter transects per plot to collect vegetation height data every two meters via high-resolution imaging by drone. Combining the measurements with the imagery, researchers built 3-D models to examine the changes in vegetation height.
Their findings showed that physical fences created a sharp contrast between grazed and non-grazed vegetation height. On the non-grazed size, grasses reached 35.8 centimeters high, and on the grazed side, grasses were a chewed-down 16.2 centimeters. Cows will graze right up to a physical fence, explains Olsen.
Semivariogram models for one physical fence plot (left) and one virtual fence plot (right), used to measure the difference in vegetation density and height. (Oklahoma State University)Distribution of vegetation height (left) and the coefficients of variation (right), used to describe the variation among the data collected. (Oklahoma State University)
But with a virtual fence, “We’re thinking that there’’ probably going to be a lot of variation in the grazing because you have different responses from the livestock themselves. You’ll have some that don’t care when they hear that alarm. Some turn around immediately.”
The results were what Olsen and colleagues had hoped to see—virtual fencing provided a much smoother transition between the tallest grasses and the more heavily-grazed sections. The mean of grass height was 46.5 centimeters in the exclusion zone, where there was no grazing; 34.7 centimeters in the boundary zone, with limited grazing; and 22.4 centimeters in the grazing zone.
Grasslands are vital to birds and pollinators, previous research suggests. Continuous grassland—not broken up into small, overgrazed segments with sharp contrasts between grazed and non-grazed grasses—allows pollinators and birds a more natural habitat. In Oklahoma, Olsen says, this might mean a safe haven for grasshoppers, eastern meadowlarks, horned larks, blue orchard bees and other grassland species.
“There are a lot of species that benefit from more variation, more variety in their habitat,” says Olsen. “If you have a fence line and you have lots of grazing on one side and no grazing on the other side, it’s really just about increasing habitat and allowing more variety.”
Two years later, Olsen is nearing the end of his graduate program and realizes how vast a topic virtual fencing can be. Several other universities and organizations around the country are conducting related research, touting the benefits for cattle and rangeland grasses alike, though federal funding sources may be tenuous at the moment. Researchers at Oregon State University are looking at how virtual fencing might help ranchers create firebreaks and cordon off cows from sensitive areas that have experienced wildfire damage.
Modernizing ranching is crucial in a changing climate, where temperature extremes are already stressing native grasses and soil, not to mention the animals and insects that share the land and vegetation with ranchers and their livestock. Rotational grazing, where livestock is moved from one fenced paddock into another to allow pasture to rest and regrow, is a practice that offers protection to pasture grasses but is time consuming for ranchers.
“Rotational grazing has been around a very long time within the cattle industry,” says J. Clay Burtrum, a second-generation rancher who co-owns Burtrum Cattle, LLC in Stillwater, Oklahoma, along with his father, Mike Burtrum. Their ranch covers 6,000 acres over three counties. “Our predecessors, our ancestors, have used [rotational grazing to be] good stewards of the land. This is not a new concept, as far as doing rotational grazing. Now, take into account the cost of fence, t-posts and supplies. Labor. That’s where virtual fence can really play a role.”
Ranchers like Burtrum have been trying out virtual fencing technology, noting how it makes aspects of a demanding job much easier. “It allows me to be away from the farm, and I can move that fence with the click of a mouse,” says Burtrum. “I’m not having to leave work early. I’m not having to go move a hot wire fence. With a click of a mouse, I can keep those cattle off that pond dam or reseeding area. It’s like you’re drawing a circle with an ink pen.”
Critics of virtual fencing point out there are some humane issues to consider. For instance, whether the cattle are harmed by the electric shocks or noises, and if a rowdy herdmate pushes another cow through a virtual boundary that leads to unnecessary jolts. Out of Burtrum’s 500 cows and 1,000 stocker cattle, 80 are wearing the collars. He doesn’t put collars on calves or bulls. Wearing the collars, he explains, doesn’t affect the way the cows eat or drink.
“Much like that dog that sees the rabbit and runs down the road, we have the same thing with cattle. I have 8 or 10 head that maybe don’t respect that virtual fence. They don’t care what the shock is. Now the shock is set. I can’t turn it up on those certain cows, and say, ‘Daggummit, I’m going to make you stay in there,’ ” Burtrum says. “You got some new cattle in or something, you train them. It’s beep, beep, beep, shock. You set those boundaries to train the cattle.”
As with any kind of technology that needs to withstand extreme weather and thousand-pound animals, some issues can arise with the collars. Batteries need to be replaced twice a year. GPS locations might not be entirely accurate. “On a 103-degree day in the middle of July, that cow is going to go stand in the pond,” Burtrum says. “That cow’s submerged up to her belly. Now you’ve submerged that collar in there. Some of the technologies are not quite waterproof.”
Given the upsides to virtual fencing, Burtrum says he’s not ready to dismantle his property’s traditional boundary fences just yet. “You still need those perimeters. But the overall grand scheme of things, it’s been a great project. I’m excited for what we can do to enhance it.”
Rebecca Owen is an Oregon-based freelance writer, community college writing instructor and cellist. She obtained an M.F.A in Creative Writing from Minnesota State University Moorhead, and an M.A. in Science Writing from Johns Hopkins University. She was the recipient of the Frank Allen Field Reporting Award from the Institute for Journalism and Natural Resources and the Oregon Literary Arts Walt Morey Creative Nonfiction Fellowship. Her writing and reporting has been published in Eos, Temblor Earth News, Equus and National Geographic.
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