Toxic and Poisonous Plants for Horses

By Josie F. Turner, Journalist specialized in Animal Welfare. March 13, 2017
Toxic and Poisonous Plants for Horses

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"Health" can be defined as the complete state of well-being that allows us to enjoy an optimal quality of life; it doesn't just apply to humans, but also to animals. Of course, a state of health is especially important for the animals that live with you, or with which you have created a special bond.

Living beings can suddenly fall ill as a result of alterations in their physiology, but on numerous other occasions their health is compromised by an exogenous - that is, external - agent. This doesn't always happen because of a pathogen, like bacteria or viruses, but a poisonous or toxic substance.

Your horse is also susceptible to falling ill if it consumes a harmful substance accidentally. In order to help you identify toxic substances and prevent this kind of accident, in this AnimalWised article we'll go over the different toxic and poisonous plants for horses.

You may also be interested in: Plants that are Toxic for Dogs

Why can plants be dangerous for horses?

Even if you keep your horse's immediate environment in the best possible conditions, when you take your companion out for a ride it can become exposed to serious risks and dangers to their health. It's important to check the area where the horse usually grazes in order to identify the plants that can be toxic or poisonous for its organism.

Your horse has easy access to all sorts of plants, herbs and berries that can be dangerous for your animal; not just because they can be poisonous, but also because horses have a delicate digestive system and the consumption of certain substances can cause cramps and other complications.

Toxic and Poisonous Plants for Horses - Why can plants be dangerous for horses?

What are toxic or poisonous plants for horses?

Here you will see what plants are poisonous for horses that are commonly found in fields and meadows:

  • Black wattle or Australian acacia: Causes anorexia, muscle weakness, depression and cramps.
  • Acorns: Only poisonous for horses in large amounts, but they can cause cramps, constipation, abdominal pain and kidney damage.
  • Oleander: Highly poisonous, as it can cause the horse to suffer a cardiac arrest.
  • Field or common horsetail: Destroys the vitamin B in the horse's body.
  • Hemlock: Highly toxic plant that contains a deadly poison that affects horses and other animals, including humans.
  • St. John's wort: Poisonous for horses' liver, it causes a specific type of liver damage that ends up causing hypersensitivity to sunlight manifested in sores in the unpigmented areas of skin. A strong poisoning may even be fatal.
  • Laurel: Poisoning in horses is manifested through vomiting and diarrhea, but it can also have affects on the heart, to the point of being fatal.
  • Rhododendron: Contains a toxic substance called grayanotoxin that can cause death within hours of consumption.
  • Groundsel: Very poisonous plant that specifically affects the horse's liver and can end up causing the progressive destruction of this vital organ.
  • Yew: Poisoning from yew is as lethal as it is fast. There are some cases in which the horse has been found dead with the leaves still in its mouth.
  • Algae: Found in ponds, poisoning in horses causes tremors, difficulty in coordinating movements and hypersensitivity. Horses can die within a few hours of algae poisoning.
  • Belladonna or deadly nightshade: Poisoning causes cardiac arrhythmia, dilation of pupils, muscle tremors, blindness and seizures. It is fatal.
  • Foxglove: Has a significant impact on the heart, to the point that foxglove poisoning can cause a horse to die.
  • Cottonthistle: In order to suffer from cottonthistle poisoning, the horse would need to consume large quantities of this toxic plant over a minimum period of 30 days. Poisoning can be noticed through facial paralysis and edema.
  • Broccoli and cauliflower: These vegetables aren't poisonous for horses, but they can cause gases and cramps in the horse's delicate digestive system, leading to intestinal disorders.
  • Ragwort: Highly poisonous, causing irreversible damage to the horse's liver.
  • Bryony: Causes diarrhea, seizures, sweating and increased urination.
  • Sudangrass: Affects the horse's respiratory system, up to the point of killing by respiratory paralysis.
Toxic and Poisonous Plants for Horses - What are toxic or poisonous plants for horses?

Other toxic and poisonous foods for horses

The previously described plants are the most toxic and poisonous for horses, but there are a few more you should prevent your horse from eating as they can have negative effects on its health. These forbidden plants include:

  • Wormwood
  • Male fern
  • Golden chain (Laburnum)
  • Buttercup
  • Meadow buttercup
  • Monkshood
  • Henna
  • Tomato plant
  • Potato
  • Pepper
  • Onions
  • Ground ivy
  • Cedar (Thuja)
  • Henbane
  • Jimson weed
  • Maple
  • Damson plum
  • Fir tree
  • Saffron crocus
  • Bluebell
  • Green peas
  • Hydrangea or hortensia
  • Lupin
  • Red clover
  • Iris
  • Spurge

Symptoms of poisoning in horses

If your horse has been poisoned by a toxic or poisonous plant, it is likely to manifest some of the following symptoms:

  • Loss of balance
  • Excessive salivation
  • Apathy
  • Drowsiness
  • Loss of appetite
  • Rashes
  • Abdominal cramps
  • Diarrhoea or constipation
  • Edema

If you notice any of the aforementioned symptoms in your horse, you should urgently contact the vet.

Toxic and Poisonous Plants for Horses - Symptoms of poisoning in horses

Preventing poisoning in horses

To prevent your horse from consuming toxic or poisonous plants, you should provide it with an environment in which it can graze safely and exercise caution when moving it to an open field. Moreover, you should take the following into account:

  • Learn to identify the toxic and poisonous plants for horses, and remember that they're harder to classify when they're not in bloom.
  • Remove these plants from the horse's surroundings. Root them out and cover the holes in the ground with salt so that they don't grow back.
  • Take caution if you see trees with berries, as the majority are poisonous.
  • Give your horse a safe, fenced-off enclosure.

Don't miss the following articles:

Toxic and Poisonous Plants for Horses - Preventing poisoning in horses

If you want to read similar articles to Toxic and Poisonous Plants for Horses, we recommend you visit our Extra care category.

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1 comment
pam johnson
We have sunset maples and October glories, crimson king should we move or cut these trees down. They are close to our horses pastures. Thanks
Administrador AnimalWised

It depends on whether the horse has access to the trees. It is likely the horse knows not to eat the, but the risk would be if they escaped and ate them out of curiosity. It's up to you to assess the dangers and likelihood of whether they will be in a position to eat them.
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