A YEAR-LONG grazing trial in the United States has demonstrated high rates of compliance for cattle and sheep managed with virtual fencing technology.

Oklahoma State University student Megan Weil addressing the Champion Station field day at Blackall in Central Queensland last week.

Results from the Oklahoma State University study were presented at last week’s field day on Blackall’s Champion Station by masters student Megan Weil, who is currently on a research exchange to Australia, working at Gyranda Santa Gertrudis Stud near Cracow in Central Queensland.

Ms Weil said the Oklahoma trial evaluated three grazing scenarios: sheep and cattle grazing together within the same virtual paddock, each species grazing separate virtual paddocks within the same pasture, and one species confined by virtual fencing while the other had unrestricted access.

She said the study showed high rates of compliance, with sheep (99 percent) slightly exceeding cattle (96pc), which came as a surprise to the researchers.

“I would not have thought our levels would have been very high with our sheep, just based on previous experience of sheep, but they proved to learn virtual fence better than our cattle did, which was a big surprise for all of us,” she told the field day.

“Our cattle also learned the system very well, so we had overall very high compliance.”

The compliance figures were based on GPS location data recorded by each collar throughout the trial.

Collars reported every animal’s position at least every 15 minutes, with reporting frequency increasing as animals approached a virtual boundary.

On average, each collar generated about 96 GPS location points per day, which gave researchers with a substantial dataset to assess compliance with virtual fencing technology.

The trial used the “nofence” virtual fencing system, while the Vence and Halter systems were also used for another trial  exclusing cattle environmentally sensitive riparian areas, which also showed high 98pc plus compliance rates.

Animals quickly learn the boundaries

Researchers also looked at how quickly animals learned to respond appropriately to the virtual fence by comparing the number of audio warnings with electrical cues delivered by each collar.

As livestock approach a virtual boundary they first receive an audio cue to turn back toward the grazing break, but if they continue toward the boundary the number of audio cues ramps up, culminating in an electrical cue.

Both sheep and cattle showed strong learning over the course of the study, with the number of electrical cues declining as the trial progressed.

However, sheep consistently demonstrated a higher ratio of audio cues to electrical cues than cattle, suggesting they were less inclined to challenge the virtual boundary.

“Cattle were way more willing to push that boundary,” Ms Weil said.

“We saw that early on in the study, but we saw the overall number of electrical cues decrease over time in those species, so surprisingly high learning rates.”

She said the results demonstrated virtual fencing could provide a reliable management tool for multi-species grazing operations.

“Overall, having such a high level of compliance indicates to us that this is a really reliable and effective system for our multi-species grazing producers.”

Why are some non-compliant?

Asked for her thoughts on why some animals were non-compliant, she said it was likely to come down to individual animal variation.

“You’re never going to have 100 percent with any animals. That can just be a stubborn heifer that is more motivated by food than she is by the deterrent.”

A technology malfunction or operator error were also possible explanations.

“So we certainly had some trial and error when it came to putting some collars on animals and getting that fit just right,” she said.

“So if the collar is too loose they may not feel the electrical pulse like one that is fit a little tighter, so there is not a perfect system that exists just yet.”

She said some shortfalls in technology she had encountered in their technology trials included limitations in cellular service in some areas, while in another case lightning struck a tower.

“So that does present some logistical challenge,” she said.

But overall she believed those issues “are pretty minor compared to the overall benefits”.

Training remains essential

While compliance was high, Ms Weil stressed that producers should still expect an initial training period and recognise that individual animals vary.

She told producers that virtual fencing, like conventional fencing, should not be expected to deliver perfect compliance from every individual animal.

But she also noted that the technology complements the social behaviour of herd animals. Their research had shown that when one animal responded to an audio warning, others nearby often turned away before reaching the virtual boundary themselves.

“What we found is in a group scenario, if one cow’s collar went off, we would see cows five feet behind it turn around,” she said.

She recommended allowing between three days and one week for animals to become accustomed to the system, depending on the production system and management approach.

Practical opportunities for producers

Ms Weil said the research is attracting strong interest in the United States as ranchers look to diversify their enterprises and improve pasture utilisation.

Ms Weil said one of the strongest drivers had been producers integrating sheep with cattle to generate additional income while making better use of pasture and managing parasite burdens by grazing at different heights.

Sheep in the study successfully grazed brush-infested areas that machinery could not access.

The Oklahoma research is now being expanded to include goats in three-species grazing systems with sheep and cattle, and also investigating how heat, rain and high wind influence virtual fence performance.

She said future studies will also look at how uncollared calves affect compliance. While that data was yet to be formally analysed and further investigated, she said anecdotal observations suggest calves remain close to the herd and have little impact on the behaviour of collared cows.