Behaviour and Movement Activity of Stallions and Geldings in Group Housing

There has been little research on the social behaviour of stallions and geldings kept together in group housing systems. The aim of this study was to investigate differences in behaviour and movement activity between stallions and geldings kept together in group housing. Behavioural observations and GPS measurements were conducted in Germany from July to September 2024 in four mixed groups of horses in Germany. The groups comprised 35 animals, 18 stallions and 17 geldings. The horses were observed for three consecutive days over eight hours per day. No injuries or stereotypic behaviours were observed throughout the observation period. Stallions displayed significantly higher levels of affiliative, agonistic, dominance, ritualised, reproductive and play behaviours than geldings (all p < 0.05). However, attack, threat, comfort, avoidance, and resting behaviours, as well as movement activity did not differ significantly between stallions and geldings. Greater space availability per horse was associated with increased comfort, resting, reproductive and play behaviours, and dominance behaviour decreased and attacks tended to decrease with increasing space availability. The horses moved an average distance of 2.36 km during the observation periods.