Restricting a horse’s dietary intake to encourage weight loss might result in behavioral changes, including aggression, stereotypies, or increased food consumption when it becomes available. To combat these behavioral changes while still encouraging weight loss, researchers evaluated the effects of strip-grazing and track-grazing systems on equine weight loss and behavior.
Strip vs. Track Grazing Systems
The strip system limits grazing to a rectangular portion of a field—an area property managers can modify by moving the fencing. As horses graze, digestible energy intake decreases until the fencing is moved to a new area. The track system involves fencing a track around the perimeter of a grazing area and gradually increasing its size to encourage movement.
Study Population
In this study, Kirton et al. divided 35 ponies on full-time pasture into four groups of seven to 10 ponies. Each group spent four weeks on a strip system and four weeks on a track system over eight fields. The horses lived together for three months prior to the experiment, so social relationships were stable. They did not receive any supplemental feed. The study was conducted during July and August, allowing the ponies to meet their nutrient requirements from pasture grass alone.
Study Results
Despite using these systems for weight reduction, the ponies’ body weight, body condition scores, and cresty neck scores did not change during the four-week periods, probably due to the experiment’s short duration. The ponies grazed about 68% of the time in either system. However, the researchers observed notable differences between the two systems:
- The ponies traveled further distances on the track system, and movement increased each week. (It’s worth noting that free-roaming horses move about 11 miles/day, and these ponies only roamed about 4.3 miles/day.)
- Ponies on the track system exhibited less aggression than ponies on the strip system, possibly due to their closer proximity in the rectangle.
- Only one pony exhibited crib-biting and only on the strip system.
- Ponies grazed more in the morning, with no differences between grazing systems.
Final Thoughts
The authors concluded, “This study supports the hypothesis that more restrictive management practices like strip grazing can have a negative impact on behavior and welfare of ponies. The track system may promote more movement and positive welfare compared with strip systems.” Increased movement might provide other physical health benefits. More studies are necessary for longer periods to determine if these systems are useful for weight control.
Reference
Kirton R, Sandford I, Raffan E, et al. The impact of restricted grazing systems on the behavior and welfare of ponies. Equine Veterinary Journal August 2024; DOI: 10.1111/evj.14411.
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