Black Walnut Shavings and Horses

Horsemen may use sundry materials to bed horse stalls—peat moss, shredded newspapers, straw, old but clean hay, and any number of wood-milling byproducts, including shavings and sawdust. Whatever the bedding choice, safety remains a priority, so any material that contains potentially harmful bits—including glass or fiberglass shards from mills, or toxic weeds in straw or hay—should be rejected wholesale. One danger occasionally hides inconspicuously among the fluffy, bouncy curls of wood shavings: black walnut remnants.

Horses that come into contact with black walnut byproducts usually fall victim to laminitis. Repeat: usually, not may or could; the likelihood of laminitis is profound. Horses are extremely sensitive to black walnut shavings or sawdust, and though researchers aren’t sure of the exact mechanism that links cause and effect, there’s no question a connection exists.

Once bedded with black walnut byproducts, horses begin to shows signs of laminitis in as little as 10-12 hours. Signs include reluctance to move, shifting weight from limb to limb, increased digital pulse and hoof temperature, and positive response to hoof testers. Unlike typical cases of laminitis, leg edema, at times significant, might be present.

Remember, ingestion of black walnut shavings is not necessary to result in laminitis, warned Kathleen Crandell, Ph.D., a nutritionist with Kentucky Equine Research (KER).

“This is not classic nutrition-induced laminitis. Horses must only stand on black walnut shavings or sawdust to be susceptible to life-altering founder; they don’t necessarily have to eat them. That’s reason enough to be especially vigilant in selecting bedding,” Crandell said.

If horses are removed from the black walnut bedding quickly enough and veterinary intervention sought straightaway, recovery may be possible.

Black walnut shavings should not be used as bedding for horses, no matter how diluted they might be among byproducts of other woods.