PREVENTING MAPLE POISONING
Eradicating all red and sugar maple trees that grow in or around horse properties is not practical or even advisable. But it is wise to consider the danger when choosing new trees. “When selecting trees to plant in or around horse pastures,” says Knight, “choose such trees as ash, fir, birch, hickory,
hackberry, magnolia, etc. Avoid maples, oaks, boxelder, walnut and chinaberry because of their potential toxicity.”
If there are existing maple trees on the property, take steps to reduce the risk for horses.
• Promptly remove fallen branches and leaves from turnout areas. Horses are most likely to encounter wilted red maple after a storm has dropped a tree branch or blown large numbers of green leaves into a pasture. Make it a habit to inspect turnout areas after any storms, especially one that brought high winds, and do not return horses to the area until any fallen leaves and branches have been cleared.
If you have many mature trees, consider having an arborist inspect them. He may be able to identify weaker branches, which can be pruned out safely before they fall. An arborist may also identify unhealthy trees, which can be either treated or removed before they develop significant damage.
• Rake and remove autumn leaves from pastures. As maple leaves change color and dry out each fall, their toxicity levels become high. If red or other dangerous maples are positioned where they consistently shed their leaves into turnout areas, rake and remove the leaves to keep them away from grazing horses. If maple leaf fall is especially heavy in some pastures, it may be
wisest to turn horses out in different areas for the season.
• Fence off large maple trees in pastures. Gallic acid is present in bark and branches as well as the leaves, but few horses are likely to eat enough woody material to be affected. However, if the horse is a cribber or habitually chews on trees, it is a good idea to fence off the maples. The lower branches of maple trees should be regularly pruned to keep them out of reach of horses.
• Monitor horses in dry lots. Horses who are on good pasture or have freechoice access to hay are less likely to eat enough maple leaves to do them harm. Those restricted to dry lots with limited forage may be more inclined to reach over the fence for nearby branches or eat what falls into their area. A hungry horse is more likely to eat dried maple leaves.
• Inspect hay. If your hay is grown in an area where maple trees are common, you may occasionally find fallen leaves incorporated in the bales. (This may be more likely to happen in fall cuttings.) Remove the leaves before offering the hay to horses.
• Remove maple trees when necessary. If there are a combination of circumstances that could place horses at risk, such as a horse who cribs living in a pasture with old red maple trees, it might be best to remove the trees. Double-check the identity of the trees before removing them by showing the leaves to an extension agent or horticulturalist at a local nursery. Make sure all debris, including stray twigs and leaves, are removed from the field before returning horses to the area. Better yet, have the trees cut while they are leafless, to simplify cleanup and reduce the risk of leaves being left in the field.
With these simple precautions, the chances of red maple poisoning can be greatly reduced or eliminated.