Characterization of Activity Budgets by Beef Cattle on Pasture

Abstract

Much of the cattle production cycle in western Canada occurs while grazing on open-range pasture, in which cattle exhibit complex behavior. Among these behaviors is how cattle spend their time grazing, walking, and resting. While these metrics may help explain behavioral responses and associated production, few studies have examined these attributes in cattle. This study examined cattle activity budgets using leg-mounted pedometers while grazing during summer and fall within a typical native Parkland rangeland of central Alberta, Canada. Moreover, these behaviors were evaluated relative to differences in environmental conditions (e.g., weather) and inherent animal attributes (age, RFI-fat and breed composition), and also related these behaviors to heifer and cow/calf production during the grazing season. The first study evaluated activity budgets during an unusually warm summer and fall (2021) to evaluate the impact of heat stress on behavior. Cattle were found to have greater movement, as exhibited by daily step counts, during times of elevated heat stress, as characterized by the thermal heat index (THI). Additionally, heifers had higher movement rates than cows with calves, particularly in summer. Heat stress conditions not only altered daily movement rates and lying/resting times, but also altered diurnal patterns of activity, with increased movement overnight and at midday during heat stress conditions, and reduced activity in the morning and afternoon. Fewer impacts of heat stress were found in fall as compared to summer, despite the continued occurrence of short periods of heat stress (less than a day). In a subsequent study using data from five cattle herds tested over 3 years, cow age was found to alter activity, with higher movement rates (and greater lying times) in heifers than cows, with movement further declining in older cows (up to 9 yr of age). In contrast, cattle activity on pasture had little association with either breed composition or RFI-fat (tested as a yearling in drylot). Cattle production metrics were found to depend on animal activity, with cows and heifers having greater weight gain in animals having greater daily movement rates (step counts) and reduced lying times. Additionally, several complex interactions were found between activity (step counts) and cattle age, particularly on the weight gain of calves, suggesting a need for further studies to better understand the role of beef cattle behavior (activity) on pasture, its underlying causes, and subsequent impact on cattle productivity.