The virtual-fence technology employed GPS, special collars and audio to keep cattle on the right grazing lands. Farmers set the fence boundaries, and the collars generated brief, 8,000-volt “electrical stimulus” shocks to cows that stray past the fence. The collars also issued a brief “sound stimulus” after the shocks.

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Researchers looking for ways to manage wildfires before they start used the collars on 39 cows on Oregon State University’s experimental pasture in southeastern Oregon. The state has been plagued by wildfires in recent years, fueled in part by sagebrush habitats that burn and subsequently are invaded by nonnative grasses that outcompete native species, dry quickly and provide even more tinder for future fires.

In the trial, the virtually fenced cows grazed on a fuel break within a roughly 1,000-acre pasture for a month. Twenty-three calves also grazed, although they were not collared. During that time, the cows ate 48.5 percent of the grass inside the fuel break area. The vast majority stayed within the perimeter, although cows with calves were more likely to stray as they followed their non-collared calves.

Cattle grazing “is perhaps the only tool that can realistically be deployed at spatial scales large enough to manage herbaceous fuels within fuel breaks,” the researchers write. Fire breaks created by the grazing herds can be used as staging areas by firefighting crews and help stop fire from spreading, they say.

But cattle alone cannot stop sagebrush fires, Chad Boyd, a U.S. Department of Agriculture research leader who led the study, said in a news release. “Grazing shouldn’t be seen in absolutes,” he said. “It’s one tool that can be used along with everything else.”

Those tools cannot be developed too soon: So far this year, there have been some 54,000 wildfires in the United States, and they have burned nearly 7 million acres of land, according to the National Interagency Fire Center.