Horses are highly social animals and can benefit substantially from interactions with other horses. However, group turnout can be associated with an increased injury risk from negative behavioural interactions between individuals. This can be especially problematic when restricted turnout space limits the ability to retreat from such encounters. To examine the impact of paddock space on stress responses in turned out horses, a recent study explored the effect of providing different minimum amounts of space per horse on stress levels and agonistic behaviours.
- 12 horses (6 mares, 6 geldings) from a single herd were divided into 3 groups of 4.
- Horses were stalled for 24 hours and then turned out in their groups for 1 hour.
- Three different pens sizes were available, offering either 184 m2, 263 m2 or 342 m2 of space per horse and the groups were rotated through the turnout pens over three days.
- Blood samples were taken each morning, then at 15 and 60 minutes into the turnout sessions and 60 minutes after being returned to their stalls.
- Plasma cortisol levels were measured to assess stress responses.
- Agonistic behaviours demonstrated by horses during turnout, including threatening behaviour, chasing, biting, and kicking were recorded.
- Where horses had 342 m2 each, their plasma cortisol levels were reduced after 15 minutes of turnout and 1 hour after return to their stall (P<0.05).
- No impact on plasma cortisol levels was seen when horses had either 263 m2 or 184 m2 turnout space each.
- Increased numbers of agonistic behaviours such as chasing, and kicking were observed in horses in pens providing 184 m2 per horse (P<0.001) than when in larger pens.
- There was a reduction in negative behavioural interactions between horses in turnout pens that provided 342 m2 per horse.
What does this mean?
Results for this study suggest that providing increased turnout space per horse results in lower levels of stress indicators and reduced levels of negative behaviours occurring between the horses. This suggests that maximising the turnout space available to horses can benefit their stress levels and reduce potential injury risk due to negative interactions between individuals. This study has helped in understanding of what could be considered as a minimum turnout space provision per horse during group turnout. Providing at least 342 m2 per horse may help to reduce potential injury risk and stress levels during group turnout.
Suagee-Bedore, JK., Linden, DR. and Bennett-Wimbush, K. (2021) Effect of Pen Size on Stress Responses of Stall-Housed Horses Receiving One Hour of Daily Turnout. Journal of Equine Veterinary Science, 98, 103366. https://doi.org/10.1016/j.jevs.2020.103366