Unlike humans, horses are able to extract energy from the fiber in their diet. The fiber is converted to volatile fatty acids (VFAs) by a bacterial fermentation process in the hindgut; the VFAs are then used to synthesize glucose (sugar) for immediate energy or are converted to fat for storage.

Horses need to eat a large amount of fiber each day to keep their gut active and free of problems, such as colic. A strong urge to chew on fibrous material also means horses may develop vices such as wood-chewing and stall-walking if they become bored without hay or pasture to consume. Since horses can handle only small amounts of concentrated energy in the form of grain, the bulk of the diet should be free-choice forage (hay or pasture), preferably with a lot of natural long-stem matter as opposed to pelleted hay or small cubes.

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This article originally appeared in the 2010 issue of Horses USA. Click here to purchase a copy.

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Holly Caccamise has been with Horse Illustrated and Young Rider since 2007, and in August 2019, she took over as head editor. She’s been instrumental in the production of both magazines and helped Horse Illustrated win a 2018 American Horse Publications Media Award in the General Excellence Self-Supported Publication (circulation 15,000 and over) category. Before getting involved in the editorial side of print media, she worked as an award-winning ad copywriter for Thoroughbred Times magazine. Caccamise has her MS in Animal Science from the University of Kentucky, where she studied equine nutrition and exercise physiology, and her Bachelor’s from UCLA in Biology. Caccamise has also worked as a research assistant, horse camp counselor teaching riding and vaulting, and as a top-level show groom in the eventing world, where she continues to compete her horse, Artie, at the lower levels.


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