Assessing Behavioral Responses and Adaptation of Cattle to Uncrewed Aerial Vehicle Presence

Uncrewed aerial vehicles (UAV) are increasingly used for livestock monitoring, but their presence may alter animal behavior and therefore compromise both welfare and data validity. This study evaluated the effects of UAV flight altitude, speed, repeated exposure, sex, age and breed on behavioral responses in cattle. Thirty-six cattle in three groups were exposed to 81 standardized flights conducted at 10, 20, 30, and 40 m above ground level (AGL) and at speeds of 3 and 6 m/s. Each group underwent three exposure sessions at different time intervals. Behavioral responses were scored on a four-point ordinal scale and analyzed using CLMM and GLMM. Flight altitude was the strongest determinant of response. Compared with 40 m, the odds of a higher response score increased at 30 m (OR = 5.30; p < 0.0335), 20 m (OR = 53.81; p < 0.0001), and 10 m (OR = 97.65; p < 0.0001). Flight speed, sex, age and breed had no significant effect. Behavioral responsiveness tended to decrease across repeated UAV exposures, although sensitivity analyses indicated that exposure-related trajectories differed among cattle groups. Because each exposure-interval schedule was represented by a single cattle group, the independent effect of exposure interval could not be separated from group-level differences.