Horse are inherently very curious and can be exposed to toxic plants in a variety of ways. Some toxic plants are very tasty and your horse may eat them, even if good quality feed is available.
Other toxic plants are not appetizing, and horses eat them as a last resort only if they have no access to other food sources.
Sometimes toxic plants can be mixed in hay unintentionally fed to the horse, leading to accidental poisoning.
When a horse ingests toxic plants, various symptoms can occur depending on the plant ingested.
Horse can also accidentally eat leaves and seeds from cut-outs of poisonous trees and ornamental plants that fall on pastures.
Different plants can cause different symptoms, so knowing which plants your horse has access to is important if you accidentally consume some.
This article explains the most common plants that are toxic to horses, what common symptoms they look like when ingested, and what to do if your horse accidentally consumes them.
What plants are toxic to horses?
Many plants are toxic to horses, but some of the most commonly encountered include oleander. Red maple, yew, holy alyssum, boxelder tree.
Five plants that are toxic to horses
1. Oleander: Oleander is an evergreen group and if you live in the southern or western United States, including California, Arizona, New Mexico and Texas, this plant may be in your backyard.
Orender plants can affect the heart, leading to lower heart rates, abnormal heart rhythms, and even sudden death.
Signs of addiction can occur between 30 minutes and hours after exposure.
2. Red maple: The red maple tree is located in the eastern US, west from Canada to Florida and Texas.
Although horse ingestion usually occurs in the fall, wilted or dried leaves may be available for horses in the spring and summer.
If your horse eats wilted or dried leaves of a red maple tree, it can cause damage to red blood cells and cause anemia.
Possible results include lower energy levels, lower appetite, altered respiratory respiratory symptoms, and abnormal urine color.
Your horse can develop symptoms 12-48 hours after exposure. However, symptoms can be delayed up to 5 days.
3. E: Yew is an evergreen and shrub that grows throughout the Northern Hemisphere, and is a common ornamental plant across the United States.
- This is another plant that can affect the horse’s heart, causing a drop in heart rate and abnormal heart rhythm.
- If ingested by your horse, this plant can cause symptoms very quickly, and unfortunately most affected horses are already dead.
4. Hoary Alyssum: Hoary Alyssum is a weed that often grows in areas with cold winters and hot, dry summers. It can be found in the Northeastern and North Central US and Canada.
- When your horse consumes this plant, it may cause painful foot conditions such as swelling of the legs, fever, and vertebral titis. Symptoms can occur within 12-24 hours of ingesting the plant and can continue 2-4 days after treatment or removal of the plant.
5. Box Elder Tree: Box Elder Trees are a type of maple that grows in the low, moist regions of the Midwest and the Eastern US and Canada.
- Their winged seeds can cause severe illness when eaten on horses, causing symptoms such as muscle stiffness, difficulty walking, and dark urine. This plant can be fatal just three days after being eaten by a horse.
If your horse is taking any of the above plants, contact your veterinarian immediately. While your vet is following their path, you can reach out to the Pet Poison Helpline at 855-764-7661 to determine the plant type (if unknown) and to the required one before the vet arrives. You can receive immediate instructions.
Symptoms of plant poisoning in horses
When a horse ingests toxic plants, various symptoms can occur depending on the plant ingested. Clinical signs are as subtle as mild lethargy, which can reduce appetite or become severe as follows:
Depending on the plant ingested, symptoms may develop rapidly or may be delayed several days after ingestion.
What should you do if your horse consumes a toxic plant?
If your horse consumes toxic plants, we recommend contacting your veterinarian Pet Poison Helpline At 855-764-7661, determine if the plant is toxic and if your horse needs to be seen immediately by a vet and treated.
How does a veterinarian deal with plant poisoning in horses?
As most toxic plants do not have antidotes, treatment focuses on decontamination, surveillance, and supportive care.
If you see your horse ingesting toxic plants but the horse does not show clinical signs, you can administer medical grade activated charcoal to prevent the absorption of toxins. Depending on the plant ingested and its toxicity, blood tests and urine monitoring may also be recommended.
In serious cases, your horse may require fluid support, close monitoring of heart rate and heart rhythm, and symptomatic and supportive care.
Preventing plant poisoning in horses
It is important to know which plants your horse has access to to prevent plant poisoning in the horse.
If toxic plants such as red maple, box elder trees, olendar, yew, or white alyssum are near pastures, you should remove and cover those plants and access the area where the plants should be fenced .
Cutters from toxic plants should never be disposed of in places where horses have access to them. Provide your horse with good quality all year round to ensure that your horse does not enter anything dangerous to them, Delicious feed and hay.
Sometimes toxic plants can be mixed with hay, so buying hay from a reputable sauce and checking that there are no unusual plant materials is an important step to keeping your horse safe.
If you don’t know how plants are identified on your property, reach out to the local garden center or florist in your area to quickly identify the plants.
