Virtual Fencing without Long-Term Stress for Cows
Agroscope researchers tested a virtual fencing system that delimits the pastures without a physical barrier, using acoustic and electrical signals only. The cows quickly learned the system without longer-term negative effects on animal welfare.
Virtual fencing systems are commercially available for cattle, sheep and goats, but are not allowed in Switzerland due to animal welfare concerns. Negative stress for the animals, usability and reliability are open questions.
Agroscope tested a virtual fencing system for lactating dairy cows in the lowlands as well as for heifers in the mountain region. Findings were positive: The cows learned to appropriately react to the virtual boundary after receiving an average of eight electrical pulses. This is comparable to previous studies under the respective test conditions. Most of the acoustic signals and electrical pulses occurred in the first three days. After this, the number of electrical pulses remained low and eventually dropped to zero, even when the cows were moved to a different pasture with a new virtual boundary.
How it works
Each cow wears a GPS collar linked via mobile network to a smartphone app. The information transmitted to the smartphone allows a herd to be monitored remotely. The virtual boundary is set via app. An acoustic signal is emitted as soon as the cow reaches the virtual boundary, followed by a mild electrical pulse when crossing it. The acoustic signal is in a rising pitch that makes the electrical pulse predictable for the animals. The paired sequence of acoustic signal and electric pulse is repeated up to three times at the virtual boundary. If the cow crosses all three warning zones, the stimuli are automatically deactivated and the animal owner is notified via smartphone. The current location of the escaped cow can be viewed at any time via the app.
In the Agroscope trial, the outer boundaries of the pastures were additionally secured with conventional fencing; however, there were no recordings of cows escaping from their virtually defined grazing area.
Weaker pulse than conventional fences
The electrical pulse of the collar is approx. twenty-five times weaker than that from a conventional electric fence. In addition, the neck is a part of the body that is less sensitive to pain than the nose, which is usually hit on first contact with an electric fence.
The system also reduces the number of fence collisions for both wildlife and livestock. Wildlife is able to move in its habitat without obstacles.
Animal welfare is comparable between electric and virtual fencing
To assess the stress responses of the animals during the learning process, the Agroscope researchers recorded various indicators such as activity and lying behaviour, feed intake, body weight and milk yield. There were no significant differences between traditionally and virtually fenced cows. Levels of the stress hormone “cortisol” measured in milk were comparable in both groups. As expected, there were short-term stress responses to the electrical pulse at the beginning of the learning process, such as rushing to leave the virtual fence. However, this behaviour was no longer observed once the animals had learned.
Easy to operate with numerous benefits
Fences can be moved with just a few clicks – saving a lot of time compared to traditional fencing.
Pasture management is straightforward; cows are precisely directed to pastures with ideal plant growth stage, and grazed according to their needs. It is just as easy to exclude waterlogged areas or patches containing toxic plants. This reduces the risk of grazing parasites or liver damage to the animals. Depending on the weather conditions, steep and erosion-prone spots can be fenced off. Thereby, sensitive areas can be protected from soil compaction. Moreover, weeds could also be suppressed by grazing management.
In addition, the virtual fencing system worked reliably in the mountain region with its small-scale, changing topography. Here, however, a careful placement of the virtual boundary is especially important due to the challenging conditions for both animals and technology.
The studies were conducted in the summers of 2021, 2022 and 2023. The project was subsidised by the Schweizerischer Landmaschinen-Verband [= Swiss Farm Machinery Association] (SLV).
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