Red Maple trees grow all across North America and are one of the top 10 most poisonous plants in the US to horses. Toxicity typically (but not always) occurs in the fall during leaf drop season and when pastures tend to have less available forage. Other factors such as frost, tree trimming and storm damage may also contribute to wilted leaves.
Eating as little as 1.5 to 3 lbs (even less for smaller equines) of wilted or dried leaves from a Red Maple will cause serious illness or death. Unidentified toxins damage red blood cells causing acute anemia, weakness, depression, pale to yellow mucous membranes, dark brown to red urine from the hemoglobin being released and increased respiratory and heart rate. Signs can occur from 18 hours up to five days after ingestion.
If your horse exhibits these clinical symptoms or you suspect it may have ingested Red Maple leaves call your Equine Veterinarian immediately. Your horse will require immediate medical attention.
There is no reliable treatment for horses with red maple poisoning. Prognosis is generally guarded to poor. Supportive care comes in the form of intravenous fluid therapy and blood transfusions. Horses with the best care sometimes develop complications during recovery, including acute renal failure, laminitis and colic.
The best treatment is prevention. Remove all Red Maple trees where horses are kept. Your local Extension agent can help you identify trees in or around your paddocks. Even horses with access to abundant forage will often gnaw on tree bark, exhibiting natural investigative behavior. If sufficient tree bark is consumed, it can be as fatal as wilted leaves. Horses at greatest risk for poisoning are those who are kept in dry lots with limited hay or grass. Carefully manage trees outside but near paddocks or pastures by removing all fallen limbs and branches, raking up and discarding all fallen leaves before they can end up in the pasture. Any leaves in any hay should be carefully inspected. If Red Maple leaves are discovered in the hay, discard the hay.
The Red Maple is a hardwood tree (Acer Rubrum). Its leaves are characterized by three large points, five prominent veins, a bright red stem, green topside and silver-white underside. Leaves will turn yellow and red in the fall. They may also be known as Scarlet Maples, Swamp Maples, Soft Maples, and Caroline Maples. Fresh, green leaves, like those plucked from a healthy tree, pose little risk to horses, though consumption should not be encouraged.
Once your horse is through the crisis and been cleared by the vet for the next stage of recovery, you may want to consider Massage therapy as a unique way to improve your horse’s overall health and well-being. Massage stimulates circulation to bring nourishment to tissues and speed healing, boosts the immune system, improves digestion, reduces physical and mental tension, and releases endorphins that reduce pain and leave your horse with a sense of well-being.