Loudoun farm pilots invisible fencing in Virginia push for rotational grazing

As technology has advanced over the years, invisible fences are being used for more than stopping dogs from chasing down roaming squirrels. 

At Georges Mill goat farm in Loudoun County, Molly and Sam Kroiz are using GPS collars and invisible fencing for rotational grazing, a practice that can have numerous environmental benefits, such as preventing pollution from entering the Chesapeake Bay.

While still in its pilot stage, the technology is seen as a way to encourage farmers to install more fences in order to keep cattle and other livestock out of streams while offering more flexibility to set and reset exclusion areas.

“I think it was like mid-April probably when we put them on,” said Molly Kroiz during an Oct. 11 demonstration of the approach organized by the Chesapeake Bay Foundation. “And since then it’s been a game changer.”

Rotational grazing is a farming practice that regularly moves animals who feed on ground cover to different acres of a property. As a result, livestock trample down the earth less, meaning less sediment is washed into waterways to pollute them. The vegetation becomes healthier too because waste can be more widely dispersed. 

In Virginia, officials are hoping farmers use prescribed grazing on 347,363 acres statewide as part of their 2025 Bay cleanup plan.

Prescribed grazing “will provide and ensure adequate surface cover protection to minimize soil erosion,” a Virginia Department of Conservation and Recreation document states. “The system will reduce sediment, nutrients, and pathogen loads in runoff.” 

How invisible fencing works

The collars and fencing being used by the Kroizes are from the Norwegian company Nofence and are being piloted on about 50 farms around the country. They’re anticipated to become commercially available in 2024.

The system works by attaching a collar to the goat that links with an app on a phone via cell phone service. A farmer can then use the app to draw the area where they want the collars, and thereby the goats wearing them, to stay. 

Out in the field, the collars of goats that get near the boundaries beep. If the goat doesn’t retreat from the boundary, or crosses it, the collar will send out a shock wave and a high-pitched noise. The collars don’t shock the goats when they cross back over the boundary.

“With the audio cue, the whole herd hears it,” said Molly Kroiz during the Oct. 11 demonstration. “And because they’re herd animals, they all react to similar cues. Oftentimes, they’ll react to collars that are not their own making noise, and the whole herd will turn.”

The boundaries can be saved in the app so the goats can be returned to an area they were previously in. Individual collars can be assigned to different fields, so animals can be sent to different areas of pasture at different times. There’s also an option for the collars to fit around the necks of cows.

There’s a monthly subscription fee for the app service, which comes with technical support and solar recharging capabilities that allow them to last for a couple weeks before needing to be plugged in for a recharge. Each collar costs about $200, with cattle collars going for roughly $300.

Alston Horn, a specialist with the Chesapeake Bay Foundation, which is encouraging the use of the technology, said those costs are far less than the average $8 per linear foot that farmers pay for a traditional fence, amounting to an overall price of at least $3,500 per acre.

“Do the math. We have 90 acres here, and that’s just for a perimeter,” said Molly Kroiz. “That’s not breaking it up into paddocks. It’s very expensive.”

Environmental benefits 

For farmers who want to keep animals in confined areas for practices such as rotational grazing, the ability to set boundaries with a few taps on a screen creates more options to limit livestock’s movement without as much effort as traditional fencing.

At Georges Mill Farm, Molly and Sam Kroiz will move their roughly 70 goats to different fields every day or two in the spring when the grass is growing. In warmer weather, the goats will move every two or three weeks.

Moving the livestock around prevents pastures from being overgrazed, which allows vegetation to grow deeper roots that hold on to soil better and reduce erosion. Bigger roots can also absorb nutrients from fertilizer, such as nitrogen, better than fields that have animals constantly eating the groundcover. 

“A small paddock that’s probably overgrazed, the plants can’t use it and the soil can’t hold it as much,” said Sam Kroiz.

As animals eat the plants in a pasture, they then produce waste that can help plant growth.

“What they’re doing here is taking nutrients from a field that the plants have really deep roots in, and they’re able to pull some of those nutrients up from the minerals and then redistribute them by putting them into another field, where it needs it,” said Matt Kowalski, watershed restoration specialist with the Bay Foundation.

Preventing nutrient runoff from agricultural operations into waterways has been a challenge for local, state and federal officials attempting to meet Bay cleanup goals. Among the key strategies policymakers are using are installing forested buffers and fencing animals out of streams.

“Well-managed pastures is good for water quality,” said Horn. “If our local creeks and streams are cleaner, ultimately the rivers as we go east, the Bay and everything else will have better water quality too.”

Practical benefits 

Supporters say the invisible fencing system offers more than environmental benefits: It can also provide practical benefits by letting farmers more cheaply and quickly move fences.

Some farmers who rent land may be hesitant to install fences around waterways because it requires a major investment on property where they may not always stay. The GPS system offers more flexibility.

“That frees up [Sam] to do a lot of other things that he’s doing around here,” said Molly Kroiz.

The practical benefits extend to farmers who may want to install permanent fences in flood-prone areas that are frequently damaged by high waters. An invisible boundary can be set by the pin-drops without placing a post in the ground.

Similarly, the technology lets farmers more easily move livestock away from vegetation that has attracted funguses.

“You can have a lot of issues with parasites, which will then, you know, give you vet bills,” Molly Kroiz said. “They’re not producing, they’re not growing the way they should for meat animals and aren’t producing milk the way they should for dairy animals. By rotational grazing you can break that parasite cycle by breaking that up.”

One drawback of the technology: the lack of protection for animals from predators. Dogs can provide extra security, but the absence of physical barriers leaves some vulnerable livestock more exposed.

Martha Moore, vice president of governmental relations at the Virginia Farm Bureau, said she would like to see more research into the technology’s effectiveness. Vetting will be required to ensure the state can assign pollution reduction credit to use of the technology, she added.

“I would want to see some of the testing and research to better understand how a farmer would incorporate this into their farming operation in Virginia — the reliability of these collars, the cost effectiveness and what other considerations a farmer would need to consider to implement this as a management tool,” said Moore.