Evaluating virtual fencing as a tool to manage beef cattle for rotational grazing across multiple years

Virtual fencing (VF) is a technology drawing attention for the management of grazing livestock under open-range conditions. This study investigated the use of VF collars to facilitate summer rotational grazing of beef cattle heifers and cow-calf pairs. Specifically, we evaluated the ability of cattle to initially learn and adapt to VF technology, and thereafter control their temporal and spatial use of pastures during the grazing season. Two years of rotational grazing were conducted using Nofence VF collars, with cattle also fitted with leg-mounted activity sensors. The first year involved yearling heifers naïve to VF, with the second year using the same animals as first-calf cows with calves. Heifers adapted to VF boundaries in 5-7 days, with an electrical pulse to audio cue ratio (E:A) of 17.9 % (±18.4) during training, decreasing to 5.2 % (±11.2) while rotational grazing. One year later, cows with prior VF experience had an E:A ratio of 1.6 % (±1.1 %) and 2.2 % (±1.6 %) during re-training and grazing, respectively. Cattle remained within VF boundaries more than 99 % of the time, though learning patterns varied by animal cohorts (age/reproductive groups), and among individuals. No associations were found between the number of VF stimuli and animal characteristics or performance. Animals with greater movement, as exhibited by step counts, experienced greater audio cues (r_s ≥ +0.087), and as heifers, greater electrical pulses (r_s = +0.21). Stocking rate had a direct positive association with the frequency of audio cues (r_s = +0.36) and electrical pulses (r_s = +0.25) for cows, but not heifers. We conclude that cattle can readily learn and be compliant with VF boundaries, and that VF technology can be used to facilitate rotational grazing through the remote movement of cattle among virtual paddocks. Overall, these findings support VF's potential to enhance cattle management flexibility and control forage use, thereby providing an innovative 'fenceless' tool to balance ongoing pasture use with grassland sustainability.