Is virtual fencing technology at your fingertips?

As Albertans, and Canadians, we eat a lot of beef and consume a lot of cow products such as milk, cheese, and butter. The cattle industry is a big part of our lives, even if we don't realize it. One of the most common methods of feeding cows is grazing them on rangeland. Grazing management is important to protect the environment and to ensure cattle productivity. Unfortunately, current grazing management practices are time consuming, labour intensive, and expensive. Virtual Fencing is a new technology that could provide increased control over cattle and grazing, while minimizing labour and cost.

The objective of this study was to investigate whether virtual fencing will work at all in Alberta, whether it might be a viable option for cattle producers to pursue, and to discover factors that might affect the success of the system.

In this study I used 51 Bos taurus cattle(2 bulls and 49 females) and 6 different virtual pastures. I grazed the animals rotationally through all of the 6 pastures. One rotation was approximately 7 days long, and the trial was 8 rotations, for a total of 56 grazing days. The virtual fence was used to control their access to grass and water. The collars tracked all of the virtual fence interactions, which I used to characterize virtual fence success or failure. Stratified random forage biomass samples were taken during three grazing phases per rotation (early, mid, and late grazing). These samples were used to estimate forage supply throughout grazing. The animals were weighed before and after the trial, and every two weeks during. The weights were used to track welfare and to calculate the amount of forage consumed by the herd (forage demand).

The collars recorded every audio warning and electric shock, and every fifteen minutes recorded location and environmental data, such as temperature and humidity. I used a linear regression model to determine if the number of virtual fence interactions changed over time. I concluded that there may be a weak positive relationship where audio warnings increase over time (r=0.267, p=0.0265), and that there is a strong negative relationship where electrical shocks decrease over time (r=-0.489, p=1.34^-5). I believe this means that cattle were not highly motivated to avoid audio warnings, but that they learned to avoid electrical shocks by listening to the warnings.

The amount of forage that was available in the pasture (forage supply) and the amount of forage needed by the herd of cattle (forage demand) were used to determine grazing pressure, or the ratio of forage supply to forage demand. A higher grazing pressure ratio means that there was more forage supply, and therefore less grazing pressure placed on the system. As the grazing pressure ratio gets smaller, there is more pressure placed on the system. Every grazing rotation was divided into three phases: beginning, middle, and end. The average grazing pressure ratios for each grazing phase were: beginning: 2.90 (SE=0.650); middle: 1.95 (SE=0.578); and end: 1.35 (SE=0.403).

I used a linear regression model to determine if grazing pressure affected how many warnings and shocks cattle were experiencing. There was a moderately strong relationship showing that audio warnings increased when forage supply decreased (r=-0.343, p=3.97^-3), but there was no significant relationship between electrical shocks and grazing pressure (r=0.081, p=0.51). This is very interesting, as it implies that even though cattle experience more audio warnings under greater grazing pressure, that does not increase the number of shocks. This supports my conclusion that the cattle learned to use the audio warning to avoid electric shocks.

Based on the above preliminary results, I propose that virtual fencing has the potential to be a new tool that will change how cattle farmers in Alberta manage their animals. I also conclude that the grazing pressure values I observed caused an increase in audio warnings but no increase in electrical shocks. More research is needed to explore more intensive systems and more factors that may impact the success of virtual fencing systems.