A two-stage method to approach weaning stress in horses using a physical barrier to prevent nursing

⿢Two-stage weaning temporally separates nutritional from physical separation.⿢Two-stage weaning had minimal impact on indicators of stress.⿢Physical separation increased vocalizations, aggression, and running in foals.⿢Physical separation increased fecal cortisol in mares and foals. Many domestic horses are weaned through abrupt physical separation of the foal and mare. Deviations from normal behaviours testify that this abrupt method has an adverse effect on the well-being of both mares and foals. To reduce negative changes in behaviour and physiology induced by weaning, a two-stage approach was tested: the first stage achieved nutritional separation by means of an udder cover to prevent nursing, and the second stage of physical separation occurred four days later. Behaviours (standing, walking, running, eating, drinking, nursing, aggressing, vocalizing) of mares and foals weaned either by abrupt physical separation (control; n=8), or two-stage (TS; n=7) were recorded in real time for 8h/d, and triaxial accelerometers recorded lying time of mares and foals 24h/d. Heart rates and global position were recorded on foals during live observations, and fecal samples from mares and foals were collected for cortisol analysis. Behavioural and physiological data were analyzed using a mixed model for repeated measures. No treatment effect was observed in foals, however physical separation induced an increase in vocalizations (0.3±0.13 versus 56.9±39.3 vocalizations/foal/d±SEM; p