Autumn Blaze Maples and horses

Asked November 14, 2013, 11:48 AM EST

We were already to plant 4 of these trees when the neighbor across the street informs us that the trees are harmful to horses and can cause horses to become anemic and can cause death is this true?

Whiteside County Illinois

1 Response

Hi -

Yes. Ingestion of dried or wilted, but not fresh, maple leaves is associated with toxicosis. Toxicosis normally occurs in the autumn when normal leaf fall occurs or after summer storms. Wilted leaves in a horse pasture are normally the result of fall leaf shed, trimming, frost, and/or wind or storm damage. Red cell damage has been reproduced in horses ingesting 1.5 to 3 pounds of dried leaves per 1,000 pounds of body weight. Horses are the only species for which maple leaf toxicity has been reported.

Symptoms include depression, lethargic behavior, and anorexia with dark red/brown urine after the first day of ingestion.

We do not recommend planting maples tress in or near horse pastures. In pastures with existing maple trees, branches should be kept out of reach of horses (i.e., trimmed above their reach). Horses should be fenced out of areas where wilted maple leaves are plentiful.

For more information, visit http://www1.extension.umn.edu/agriculture/horse/pasture/maple/