Wood-Chewing in Horses: Examine the Diet for Cause

Horse chewing on a wood post.
Horse chewing on a wood post. Jeffery Wright

Newsdate: Wed June 20, 2018, 10:39 am
Location: GUELPH, Ontario

Owners of wood-chewing horses generally cite boredom as the basis for the frustrating vice also referred to as a stereotypy. Is monotony the motive behind wood-chewing? Or has blame been misplaced?

Horse-chewed wood rail on gate.

Horse-chewed wood rail on gate

Is monotony the reason for wood-chewing in horses? Or has blame been misplaced?.
© 2017 by Lostinfog

“I’ve seen a lot of pastured horses with access to acre upon acre of lush grass sidle up to a fencepost or plank and begin nibbling at it, systematically shredding it,” said longtime nutritionist Kathleen Crandell, Ph.D., Kentucky Equine Research (KER).

Like many vices, wood-chewing poses certain risks to horses. Ingestion of splinters can cause health problems, including oral wounds, a puncture anywhere along the gastrointestinal tract, or impetus for enterolith formation. Old-timers list wood-chewing as a possible reason for recurrent colic.

“This question comes immediately to mind: how can a horse with succulent pasture grass at its heels be tempted by a dried-out, painted fence board?” asked Crandell.

The answer lies hidden in that question.

“Horses crave fiber, and green grass contains little fiber. In fact, growing grass is composed nearly entirely of water. When a horse desires fiber, it heads to the fenceline when no hay is available,” she said. “Horses possess digestive tracts designed to process lots of fiber, but fencing materials offer the wrong kind, because it is virtually indigestible.”

A dietary change might help alleviate the need to chew wood, according to Crandell. This can be as simple as offering hay in addition to pasture. “Horses have an evolutionary need to chew roughage, and growing grass doesn’t fulfill that need,” said Crandell.

Unfortunately, offering long-stemmed forage such as hay doesn’t always dissuade a horse from chewing wood. Other methods of discouraging wood-chewing involve covering surfaces with metal, wire, or taste deterrents. Confirmed chewers can be outfitted with a muzzle that prevents them from grasping wooden objects with their teeth but allows free-choice eating.

As a final note, wood-chewing might be aggravated by hindgut acidosis, a disturbance in the gastrointestinal tract pH that causes some horses to engage in stable vices

Dr. Kathleen Crandell instructs Equine Guelph’s online course: Advanced Equine Health through Nutrition. To view all Equine Guelph online courses including Nutrition offerings

Article courtesy of Kentucky Equine Research

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EquiMed Staff

EquiMed staff writers team up to provide articles that require periodic updates based on evolving methods of equine healthcare. Compendia articles, core healthcare topics and more are written and updated as a group effort. Our review process includes an important veterinarian review, helping to assure the content is consistent with the latest understanding from a medical professional.

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