USDA-Colorado State trial: virtual fences kept steers in place 94–99% of the time but cut weight gain 9%

September 2025 — Virtual fencing kept yearling steers inside their assigned grazing areas 94–99% of the time in a USDA and Colorado State University trial, but the managed steers gained 9% less weight, ending the season 7.3 kg lighter than cattle left to roam. Here's what happened, what it cost, and what went wrong.

Cost and outcome (as of Sept. 10, 2025)

Outcome: 94–99% containment; growth down 9%, or 7.3 kg per steer. (Raynor et al., Frontiers in Veterinary Science, Sept. 10, 2025)
Methane: no consistent reduction: 216 vs 221 g per head per day overall. (Raynor et al., Frontiers in Veterinary Science, Sept. 10, 2025)
Cost: the authors cite the "current high costs" of virtual fencing and lost revenue from lower gains; no dollar figure. (Raynor et al., Frontiers in Veterinary Science, Sept. 10, 2025)
Weather: April–August rain was 78% of normal; forage was 61% of average. (Raynor et al., Frontiers in Veterinary Science, Sept. 10, 2025)

How the trial worked

Researchers split 120 British-breed stocker steers, about 12 months old and averaging 382 kg, across two pairs of roughly 130-hectare pastures that were physically fenced. In each pair, one herd was rotated among sub-pastures with active virtual-fence collars, and the control herd wore inactive collars and roamed the whole pasture. (Raynor et al., Frontiers in Veterinary Science, Sept. 10, 2025)

The collars were Vence units from Merck Animal Health, set to log locations every five minutes. Methane was measured with automated head-chamber systems (GreenFeed) placed in all four pastures. (Raynor et al., Frontiers in Veterinary Science, Sept. 10, 2025)

One pasture pair had a diverse mosaic of soils and plant communities; the other was a Sandy Plains site with western wheatgrass, needle-and-thread and blue grama. (Raynor et al., Frontiers in Veterinary Science, Sept. 10, 2025)

Results

Virtual fencing kept 94–99% of steer locations in the desired areas, though five of the 60 managed steers made short daily excursions over the boundary every day. (Raynor et al., Frontiers in Veterinary Science, Sept. 10, 2025)

Managed steers grew more slowly in both pasture pairs. (Raynor et al., Frontiers in Veterinary Science, Sept. 10, 2025) The authors said it's unclear whether that came from more selective foraging, extra energy spent, or the plant communities they chose. (Raynor et al., Frontiers in Veterinary Science, Sept. 10, 2025)

For the 54 steers that met visit criteria for the methane system, the Sandy Plains virtual-fence herd emitted 187 g a day against 223 g for controls, while in the mosaic pair it emitted 241 g against 223 g. (Raynor et al., Frontiers in Veterinary Science, Sept. 10, 2025) In the mosaic pair, methane per kilogram of daily gain was 431 g for managed steers and 324 g for controls; by our arithmetic, that's about 33% higher. (Raynor et al., Frontiers in Veterinary Science, Sept. 10, 2025)

In the Sandy Plains pair, lower methane came "at the cost of a 12% decrease in kg gained per day," so emissions per kilogram didn't differ over the season. (Raynor et al., Frontiers in Veterinary Science, Sept. 10, 2025)

What the authors conclude

Virtual fencing "is not a straightforward solution" for managing the links between forage, growth and methane in stocker steers on extensive rangeland, the authors wrote. Programs that pay for adoption to cut methane "should address these practical tradeoffs." (Raynor et al., Frontiers in Veterinary Science, Sept. 10, 2025)

They said costs depend on the technology, topography, cellular coverage and pasture size. (Raynor et al., Frontiers in Veterinary Science, Sept. 10, 2025)

Who did it

The 12 authors, led by Edward J. Raynor, are from Colorado State University, USDA's Agricultural Research Service and the Thunder Basin Grasslands Prairie Ecosystem Association. A USDA Conservation Innovation Grant and a Western SARE grant partly funded the work, and the authors declared no commercial conflicts. (Raynor et al., Frontiers in Veterinary Science, Sept. 10, 2025)

What went wrong

Lighter cattle. The managed steers gained 9% less, which the authors tie to foregone revenue. (Raynor et al., Frontiers in Veterinary Science, Sept. 10, 2025)
Mixed methane. Emissions fell in one pasture pair and rose in the other; per kilogram, they rose in the mosaic pair. (Raynor et al., Frontiers in Veterinary Science, Sept. 10, 2025)
Drought year. Rain was 78% of normal and forage 61%, which may not generalize. (Raynor et al., Frontiers in Veterinary Science, Sept. 10, 2025)
Small methane sample. Only 54 of 120 steers met the measurement criteria. (Raynor et al., Frontiers in Veterinary Science, Sept. 10, 2025)
What we don't know yet: whether a different rotation plan or a wetter year would avoid the weight penalty.

Our follow-up question for Colorado State University and USDA-ARS

Is the trial being repeated in 2025 with different rotations, and what did the collars cost per head?

Sources

Raynor E.J. et al., “Incorporating virtual fencing to manage yearling steers on extensive rangelands: spatial behavior, growth performance, and enteric methane emissions,” Frontiers in Veterinary Science 12:1637190, Sept. 10, 2025, doi:10.3389/fvets.2025.1637190. frontiersin.org

Disclosure: [not in copy] Editor placeholder