Rewilded Highland Cattle in conservation grazing may not groom more when horseflies are present and temperature is higher

Grooming behavior in domestic cattle serves various functions, including hygiene maintenance, social bonding, and stress alleviation. We examined the grooming patterns of rewilded Highland cattle, to describe their behavioral adaptations and responses to environmental factors in a conservation grazing system. We observed 21 Highland cattle in a French nature reserve from November 2020 to September 2021 using mixed focal and scan sampling methods, recording a total of 1225 grooming bouts. Grooming primarily consisted of self-grooming (83%), followed by tree-grooming (16%), and social-grooming (1%). The average grooming duration per bout was 48.2 seconds per 15-minute interval, indicating a stable and consistent grooming pattern across all observed cattle. We used linear and generalized mixed effect models to assess the effects of environmental factors such as the presence of horseflies, the Temperature-Humidity Index (THI), and habitat type. Our results showed that grooming behavior was influenced by habitat and group, while environmental stressors had only minor effects on grooming duration and frequency. This limited response may be attributed to the relatively low density of horseflies in our study area and the opportunity of adaptive behaviors, such as wallowing, to manage heat and ectoparasites. By examining grooming behavior under near-natural conditions, this study provides a baseline for understanding behavioral patterns and adaptations in rewilded cattle, while also serving as a potential reference for identifying behavioral changes in domestic cattle and informing future management practices.