Autumn's Deadly Bounty
While many poisonous plants often give off an unpleasant odor, or perhaps have a texture that normally would repel a horse, in times of drought or if pasturage is poor, your horse might be tempted to eat anything available.
The drought tolerant, noxious weed, Johnson grass (sorghum halepense) can be a real problem in pastures and hayfields where drought conditions can cause many other grasses to die out while the Johnson grass is left to flourish. Any sudan grass or sorghum when grazed after a prolonged drought or heavy frost is bad for your horse. By providing supplemental hay, your horse will not be tempted to eat large amounts of Johnson grass growing in his field during drought conditions and you then can avoid the heartache of Neuropathy (nerve damage) and teratogenesis (damaging effects to a fetus)
That beautiful red maple tree in the pasture may be pleasing to the eye in early October, but if your horse consumes those fallen leaves it could spell death for your equine friend. The toxins produced by the red maple destroy red blood cells and the oxygen supply pumping through the horse’s arteries will be insufficient to sustain its body. Should your horse become lethargic, colic, or have difficulty breathing and show signs of an increased heart rate, call your veterinarian immediately; especially if you suspect red maple leaves to be the culprit.
Honey locust or black locust trees, while rarely fatal can cause depression, poor appetite, abdominal pain, diarrhea (sometimes a bloody stool), weakness or even paralysis, and abnormal heart rhythm if your horse ingests either the bark or leaves.
Horses foraging in heavily wooded areas may end up with a mouthful of white or red oak tree leaves, which can be highly poisonous since they contain tannins. Acorns, too, can be quite toxic. A few, ingested accidentally are usually harmless but some horses will develop a taste for them and gobble them like candy unless restrained by the humans in their lives. The tannic and galic acids in the acorn can cause severe damage to a horse’s gastrointestinal system, as well as its kidneys. Symptoms can include constipation, colic, blood in the urine, dehydration, anorexia, slow or irregular heatbeat, and swelling in the legs. This problem can sometimes be hard to diagnose unless your horse has a history of eating acorns or some evidence of acorn consumption can be found in its manure.
Even those wonderful fruit trees such as apricot, peach, plum, cherry, almond, and nectarine, can be problematic if they have been damaged by frost or drought. It takes only a small amount of the leaves to sicken an animal with cyanide poisoning. Symptoms of cyanide poisoning can include rapid breathing urinary or kidney infection, convulsions and even death.
We've only touched on a few of the fall poisonous plants lurking in your pasture or forested areas, but it can definitely be seen that it is a good idea to fence off any wooded areas that could pose a health threat to your equine family. You can thus avoid the expense and heartache that could result from ignoring the existence of such plants.