Stability of equine hierarchies and the prevention of dominance related aggression.

This research article investigates the stability of dominance hierarchies in herds of Thoroughbred horses and explores methods of minimizing aggression related to such hierarchies. The researchers used a series of feeding tests to gauge the equines’ dominance and found that hierarchy among adult horses rarely changed over time. They also concluded that management tactics, such as separating pairs by a fence during feeding, resulted in reduced aggression and increased food consumption among subordinate horses.

Methods Used

• The researchers observed a herd of 10 Thoroughbred mares over a period of 18 months to determine any changes in the mares’ dominance hierarchy. Paired feeding tests were conducted twice to analyze each mare’s rank within the herd hierarchy over time.
• They also examined the offspring of both dominant and subordinate mares to determine their dominance status within their own age groups.
• In addition to the mares study, a feeding test was conducted on 8 ponies. These ponies were either kept in the same paddock or separated by a rail fence during feeding. While conducting these tests, observations were made on the time each pony spent eating and any aggressive interactions that occurred.

Findings

• The researchers noted a significant correlation between the ranks of the mares in the first and second feeding tests, indicating stable dominance hierarchies over time.
• In examining the offspring of the mares, it was observed that the progeny of dominant mares tend to be dominant in their own age groups. However, the offspring of middle and low ranking mares did not consistently occupy the same ranks within their own age group hierarchies.
• The feeding tests with the ponies showed that when pony pairs were separated by a rail fence, the subordinate pony spent more time eating and the dominant one showed less aggression. This was significantly different compared to when they fed together in one paddock.

Conclusion

• The outcomes of this study demonstrate that the dominance hierarchies of adult horse groups remain largely consistent over time.
• Offspring of dominants mares are likely to be dominant within their own age groups, although this pattern is less clear for offspring of middle and low ranking mares.
• Management practices that involve spatial separation during feeding seemed to mitigate aggressive behavior and improve feeding times, particularly for subordinate ponies.
• Such practices could be useful for minimizing aggression and potential injury risk in group feeding situations.