Daily behavioral grazing patterns of beef cattle: continuous stocking grazing

Virtual fencing is an innovative technology for managing grazing cattle using GNSS collars. Animals were contained through a paired stimulus: when they approach a virtual boundary, the collar emits audio warnings, followed, if ignored, by an electrical pulse as aversive stimuli. This study evaluated whether different grazing management systems and the use of virtual fencing affect the daily activity behavior of Limousine cows under seasonal grazing. Two groups of 13 cows each were managed for 36 days respectively under: i) continuous stocking on a 15-ha pasture (CSG), and ii) by strip grazing (SG) using Nofence® collars to gradually expand areas according to forage availability (five boundary shifts, P1-P5). Each cow wore Allflex® smart ear-tags recording time spent grazing, ruminating, and resting. Data were analyzed with a generalized linear mixed effect model, including group (CSG, SG), period (P1-P5), and time slot (00:00-04:00, 04:00-08:00, 08:00-12:00, 12:00-16:00, 16:00-20:00, 20:00-00:00) as fixed effects, and distance traveled, temperature, and gestation day as covariates. Animal and day were random effects. Hair cortisol content was also analyzed as chronic stress indicator. SG managed with virtual fencing did not affect the overall time spent grazing, ruminating, or resting, which was similar between groups. However, a significant triple interaction indicated behavioral shifts: SG cows ruminated more during the night and early afternoon, grazing mainly in the late afternoon and evening, while CSG cows showed the opposite pattern. SG managed with virtual fencing could optimize pasture management without altering physiological behaviors or increasing chronic stress measured by hair cortisol content.