Behavioural and Physiological Changes in a Herd of Arabian Mares after the Separation of Individuals Differently Ranked within the Dominance Hierarchy.
Authors: Stachurska Anna, Wiśniewska Anna, Kędzierski Witold, Różańska-Boczula Monika, Janczarek Iwona
Journal: Animals : an open access journal from MDPI
Summary
# Editorial Summary Researchers from the University of Life Sciences in Warsaw investigated how the temporary removal of individual mares affects the behaviour and physiology of those remaining in the group, specifically testing whether the social rank of separated individuals influences herd stress responses. Using twelve Arabian mares with established dominance hierarchies, the team removed either high-ranking, low-ranking, or mixed-rank three-mare subgroups for ten-minute periods and measured behavioural changes, locomotor activity and heart rate variables in the remaining animals. Separation triggered clear signs of emotional arousal—elevated heart rates and altered movement patterns—in the residual herd regardless of whether dominant or submissive mares had been removed, suggesting that horses respond to social disruption itself rather than the specific rank of absent companions. This finding has practical implications for handlers managing group separations in yards and breeding facilities: the stress response cannot be reliably predicted from dominance rank, meaning all temporary separations warrant careful observation and management to minimise welfare impact. Clinicians and yard staff should recognise that even brief social fragmentation—a routine occurrence during veterinary treatment, farriery, or training—represents a genuine stressor for herd members, and consideration should be given to minimising separation duration and providing reassurance where possible.
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Practical Takeaways
- •When separating horses from a group for farrier work, veterinary treatment, or transport, expect increased anxiety and movement in remaining horses regardless of which individuals are removed—plan accordingly for handler and horse safety
- •Dominance rank of separated horses does not predict herd response intensity; all separations are stressful events for social groups, so minimize separation duration when possible
- •Monitor for signs of emotional arousal (elevated heart rate, increased locomotion) in remaining herd members during routine separations and allow time for horses to resettle before working with them
Key Findings
- •Separation of group members elicited evident changes toward emotional arousal in the remaining herd during a 10-minute separation period
- •Herd response included increased locomotor activity and changes in cardiac parameters following separation of conspecifics
- •Response of remaining herd did not strictly depend on the dominance rank (dominant, mixed, or submissive) of the separated mares
- •Artificially assembled herds maintain sensitivity to temporary loss of members despite human management