Red Maple Poisoning in Horses

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Fall is a wonderful time to enjoy being outdoors, but with fall comes the seasonal hazard of toxic poisoning from falling leaves. Red maples are particularly dangerous to horses. They are abundant in Burke County and whenever they are stressed by drought or change of season, chemical changes within the leaves create toxins that are fatal to horses.

An abscission layer forms on each leaf stem and seals off water from the roots. The trapped chemicals within the leaf become toxic and when eaten by a horse, cause the kidneys to hemorrhage and they essentially bleed to death.

In the buds on each twig are tiny leaves which may also be a threat during winter. Horses allowed access to red maples during winter can be poisoned from browsing on these buds. Canadian vets call red maple poisoning “red snow disease”, identifiable by the trail of bloody urine through the snow, from horses who have consumed the buds.

So, identify the red maples in and around your pastures and eliminate them whenever possible. Avoid feeding hay under or around red maple trees, and manage forage to provide adequate grazing, supplementing it with good quality hay when pastures are dormant, as most poisoning occurs from accidental ingestion.

white horse in a pasture in front of trees in autumn