Virtual Fencing for Livestock: What Works Best and Where?
As the Southeast Regional Manager for the National Grazing Lands Coalition, I often get questions from producers looking to adopt new technologies for better grazing management. One of the most talked about innovations is virtual fencing. Instead of stringing miles of wire or moving physical fences, producers can now manage livestock through GPS or radio signals. It sounds futuristic, but the reality is here and it's not one size fits all. If you have ever used GPS collars or training collars for your hunting dogs, then you have already dipped a toe in this pond and understand some of the limitations.
Let's break down the two main types of virtual fencing: GPS based and radio based systems.
In this blog, I am not discussing any particular brand of virtual fence. That gets into the territory of the old Ford vs. Chevy debate and I figure that Google is our friend when researching brands and looking at reviews. Moreover, I am taking a 50,000 foot approach. Honestly, we could really get into the weeds on this topic but my goal is to introduce this technology to those who have no prior experience with it.
GPS Based Virtual Fencing
GPS based systems rely on satellite signals. Each animal wears a collar equipped with GPS tracking. A digital map boundary is created using software, and the collar delivers auditory cues (like a beep) followed by a mild electric stimulus if the animal crosses the virtual fence.
Cons: Dense tree cover, steep terrain, or deep hollows can weaken or block the GPS signal.
GPS collars can be more expensive and require frequent charging or solar assistance.
Pros: Highly flexible boundaries that can be redrawn from your phone or computer.
Useful in rotational or grazing systems where paddocks change frequently.
Works well across large, rugged landscapes.
Radio Based Virtual Fencing
Radio based systems (and this does include the cellular frequencies) use a centralized base station that transmits signals to a set boundary. As livestock approach the perimeter, the collar emits a warning, then a correction. These work best with clear line of sight between the base unit and animals.
Cons:
Radio signals struggle in hilly, forested, or brushy environments where signal bounce and blockage occur.
Less flexibility, you have to physically relocate the base unit to change boundaries (unless you run multiples and set it up as a repeater system).
Pros:
Lower power needs and often longer battery life.
Real-time control with no internet or satellite dependency.
More cost effective for small operations or flat terrain.
Terrain and Foliage: The Deciding Factor
The effectiveness of each system hinges on your land. For open fields, flat pastures, and minimal obstructions, radio-based systems are economical and reliable. But once you get into hardwoods, ravines, or mixed-use land, GPS-based fencing often provides better consistency despite its connectivity challenges. I have dealt with this exact scenario on more than one occasion while doing GPS mapping (I was caught between 2 mountains). Unless there were satellites directly overhead, you had no signal.
Signal Behavior and Line of Sight
To visualize the difference:
1. GPS signal comes from satellites above, bouncing down to the collar. It can pass through light tree cover but loses accuracy under heavy canopy or terrain breaks.
2. Radio signal travels directly from the base unit to collars. If there's a hill, dense stand of trees, or even a metal structure in the way, the signal gets distorted or blocked.
Having been an Amateur radio operator for years, understanding line of sight and how different frequencies are affected by different materials and how it all interacts has been a part of the fun (granted, many of these frequencies are outside the scope of this blog). The easiest way to explain it is how cell phone signals become degraded the further you are from the source (in this case, a tower), or when you are going into low areas and the call drops out. Same thought process with how the signal works with virtual fencing.
