5 - Effects of Virtual Fencing on Cortisol Concentrations and Behavior of Beef Cattle

Two experiments were conducted to evaluate the effects of virtual fencing on stress in beef cattle. In both experiments, cattle were contained by either physical, 2-strand electric fencing or by use of a proprietary, GPS-based virtual fencing collar, with no physical interior fencing. In both studies, hair from the tail switch was collected at the end of the experiment, and analyzed for cortisol concentration to measure the accumulated stress experienced by the cattle. Additionally, a subset of cattle were fitted with pedometers to measure behavior responses. In the initial pilot experiment, 55 heifers were grazed for 28 d in either 1 physically-fenced pasture or 1 virtually-fenced pasture. In the second experiment, 59 mature cows and heifers were grazed for 56 d in 1 of 2 physically-fenced or 1 of 2 virtually-fenced pastures (4 pastures total). In the second experiment, blood samples were also collected and NEFA and lactate were quantified in plasma. Only descriptive statistics were summarized for the pilot experiment, which indicated that hair cortisol concentrations were within published ranges for both fence types (0.39 ± 0.32 and 0.37 ± 0.15 pg/mg for physically- or virtually-fenced animals, respectively), and step count and motion index appeared elevated in the first few days of adaptation to virtual fence. The second experiment was analyzed with analysis of variance as a completely random design with pasture as the experimental unit. No effect of fence type was found for behavior (number of steps, standing time, lying bouts, or motion index; P > 0.16). Further, no difference was observed in cortisol, lactate nor NEFA (P > 0.14) concentrations due to fence type. None of this data suggests that virtual fencing is different from physical fencing in the effects on cattle stress and behavior, indicating further research and development of virtual fencing technology are warranted.