When put on a restricted diet, overweight ponies have been shown to snack on stall bedding according to research from the Liverpool University Veterinary School in Great Britain.
A group of 12 overweight ponies was divided into two groups, each given a different restricted diet of 1.25% of their body weight. They were weighed weekly and their diets adjusted accordingly. The ponies were turned out for 30 minutes daily with muzzles to prevent them from grazing.
By analyzing the manure produced, researchers determined that at least half of the animals had been eating the wood shavings in their stalls. Some had consumed more than 3 kg (about 6.6 pounds) of bedding, and five out of the 12 ponies had apparently consumed more than 1 kg (2.2 pounds) daily.
The researchers concluded that horses and ponies put on a restricted diet should be carefully monitored to ensure they are not supplementing their own diet from non-food sources.
Keeping horses turned out in a dry lot or outfitting them with a grazing muzzle may help keep them at a healthy weight without the health risks associated with consuming wood shavings. If they must be stabled, using bare rubber mats and providing stable toys to keep them occupied may be practical solutions.
Voluntary ingestion of wood shavings by obese horses under dietary restriction. GC Curtis, CF Barfoot, AHA Dugdale, PA Harris,CMcG Argo. British Journal of Nutrition (2011) 106, S178-S182