As the leaves turn orange, yellow and red in the fall, they make for beautiful scenery across pastures. However, there are some trees that you should be aware that are poisonous to your horse, especially in the fall. Such trees can cause sickness and in some cases even death in horses that consume the tree or the leaves.

Red Maple Leaves

Red Maples trees are seemingly harmless for most of the year; however, as the leaves wilt they become very toxic to horses. The wilted leaves of Red Maples produce cyanide. When consumed, cyanide blocks oxygen transport via blood cells causing the red bloods cell to die and, if high enough levels are consumed, the horse to suffocate. The toxins also cause damage to the kidneys, liver, and other organs.

How to Distinguish Red Maple Leaves

The distinctive features of Red Maple leaves with allow you to distinguish between other leaves falling that are harmless. Red Maple leaves have serrated edge, and turn red or yellow in the fall with a silvery underside.

Signs of Cyanide Poisoning in Your Horse

Curiosity and boredom can cause horses to consume the toxic leaves of Red Maples. As little as a pound consumed by your horse can be fatal. Depending on how many leaves are consumed, signs can become visible within a few hours or as long as five days after eating the leaves. A horse that has been poisoned will show signs of lethargy, food refusal, dehydration, discolored (dark red or black) urine, jaundice gums that eventually darken, increased heart rate, and increased respiration.  

Treating Your Horse For Cyanide Poisoning

The only treatment for cyanide poisoning is supportive therapy with IV fluids to dilute the toxins in the blood in less severe cases of cyanide poisoning. In some cases blood transfusions are also a possibly. If they make it through supportive therapy, cyanide-poisoned horses can then develop laminitis because blood flow has been compromised. The recovery process is then a long process with it taking more than three weeks for red blood cell counts to return to normal.

Other Plants and Trees that Contain Cyanide

Cherry, peach, and plum tree leaves also produce equally toxic levels of cyanide. Silver and Sugar Maple leaves produce slightly lower levels of cyanide when wilted, so your horse must consume to develop cyanide poisoning. When Johnsongrass or Sudan grass is injured from wilting, trampling, or frost both contain toxic levels of cyanide for your horse. In the early stages of growth Johnsongrass contains its highest levels of the toxin, which are toxic for your horse. When these grasses are cured for hay, the cyanide drops to levels that are safe for your horse to consume.

Avoiding Cyanide Poisoning

Typically, when your horse is fed high-quality hay with a good vitamin-mineral supplement they won't consume many leaves. However, they may eat them out of boredom or curiosity. Because the threshold to toxicity is so low to it best to avoid the situation all together. Relocate your horses to an area that leaves from these trees won't blow into their pen. Removing this hazard will give you one less thing to worry about with your horse and help ensure you have a happy, healthy horse.