The Effectiveness of Virtual Fencing of Bull Calves in a Holistic Grazing System

SIMPLE SUMMARY: Virtual fencing is a new way of enclosing livestock without the use of physical barriers. The system relies on GPS technology and works by deterring escapes using auditory warnings and electric impulses. This study examines the effectiveness of one such system in a rotational strip grazing regime with 17 Angus bull calves. This study also aimed to determine which bull calves were more likely to receive electric impulses. The system proved effective at containing the bull calves within the designated enclosure. The bull calves learned to associate the auditory warning with the electric impulse, and as such, received increasingly fewer impulses as time went on. However, in accordance with previous studies, there were clear differences in the number of warnings and impulses received between individuals. The results regarding which bull calves received the most impulses did not show any clear trends. In conclusion, the virtual fencing system proved to be effective and the animals learnt how to interact with the system while receiving very few impulses. ABSTRACT: Large grazers are essential for nature conservation. In order to prevent grazers from moving to unintended areas, it may be necessary to keep them inside enclosures. Physical fences present a number of problems, such as fragmenting the landscape. Virtual fencing, however, is a possible replacement for physical fencing, making it possible to enclose grazers without physical boundaries. Virtual fencing systems utilise collars with GPS technology to track animals and deliver auditory warnings and electric impulses to keep animals within predefined boundaries. This study examines how effective the virtual fencing system Nofence© is at enclosing calves in a holistically managed setting. Holistic management is a rotational grazing technique where an enclosure is grazed in small strips at a time. It is investigated whether the calves become habituated to the virtual fence and whether there is a correlation between the number of warnings received by every two calves in order to explore potential herd behaviour. Finally, this study examines which calves interact the most with the virtual fence by investigating the relationship between physical activity and number of interactions. Seventeen calves were fitted with a GPS collar from the company Nofence© and placed in a holistically managed enclosure. Data were gathered from 4 July to 30 September 2022. The study found that virtual fence was able to contain calves inside the designated enclosure, and over time the calves received notably fewer electrical impulses compared to auditory warnings. The results of Pearson’s correlation between auditory warnings received by two random calves were inconclusive, but the use of a sliding window analysis should be further explored. Lastly, the most physically active animals were the ones who received the most auditory warnings, but they did not receive more impulses. No significant correlation was found between the number of electric impulses received and the physical activity of the animals.