Are Walnut Trees Toxic to Horses? (5-Minute Read)

By Zunnun Ahmed •  Updated: 09/22/22 •  6 min read

So, you have a walnut tree on your property?

Then you better be aware of the tree’s danger to your beloved animal.

Walnuts contain a substance called juglone, which is poisonous to horses. When horses eat leaves or bark from a walnut tree, they can suffer from gastrointestinal problems like colic or diarrhea. In severe cases, juglone poisoning can even be fatal.

So, if you have a walnut tree on your property, keep your horse away from it. And, if you’re considering planting a walnut tree, think twice before doing so if you have a horse – it’s just not worth the risk!

Horses eat Walnut

Related: Make your horse happy with peppermint treats! Learn the secret recipe for delicious, easy-to-make treats your horse will love.

What about trees? Are walnut trees poisonous to horses?

While it might be an exaggeration that simply walking and pasturing under walnut trees will cause laminitis, it is best to stray from that path. 

Because if your horse is hungry and roaming under a walnut tree with no other food around, it may grind and chew on its leaves, the walnuts, and even the wood, bark, branches, and pollen. In that case, your horse is definitely in danger. (Also read more about does weed is toxic to horses?)


Wood shavings with more than 20% of walnut are poisonous to horses. 

Say you have made bedding with walnut and other wood shavings. Horses ingesting and inhaling black walnuts are susceptible to acquiring laminitis.

And here is how to prevent it……..

You can selectively remove the walnut shavings, sawdust, leaves, wood, and nuts from the pastures and anywhere else your horse goes. 

You can further snip the walnut branches within your horse’s reach and create a firm boundary near the walnut trees that your horse usually saunters to.

Why is black walnut poisonous? the science behind it

Black walnut tree poisoning has a mysterious origin. Juglone, a chemical compound discovered in the tree, was initially thought to be the culprit. 

Let me explain this…….

The black walnut trees produce the chemical juglone and may be found throughout the whole tree, but are most concentrated in the buds, nut hulls, and roots. Walnut leaves, wood, and bark all contain this toxin.

And the Fact is: Juglone is most abundant in the roots. 

The concentration level lowers with its height. Toxicity may persist long after the locals cut down a tree because rotting roots release juglone.

This toxin usually doesn’t come in contact with humans, and touching it in itself isn’t harmful, but the problem begins when you absorb it. For us people, we will only suffer slightly and be discomfited. 

But animals like horses are susceptible to walnut toxicity. Your horse’s bedding should never consist of any amount of walnut sawdust or shavings, even by mistake.

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Symptoms of black walnut toxicity in horses

The symptoms your horse suffering from black walnut poisoning will have are:

Take note: 

The symptoms can differ based on how badly they are poisoned and how long they have been exposed to black walnut poisoning.

See also: Alfalfa cubes vs alfalfa hay

Additional Info and remedy

Walnut pollen can affect both humans and animals. While it is renowned for its toxicity and causes allergic reactions to about everyone, horses are especially exposed to it. 

The responses can get severe very quickly from their mildness. The mild sensation feels like an itch inside the mouth and tongue. Fatal cases mention anaphylactic shock, hives, asthma, and throat swelling. 

There is no remedy for black walnut poisoning because the toxin it contains is unknown.

As soon as the vet identifies the issue, they should take the horse out of the bedding and treat it for acute laminitis using the most recent techniques. Usually, this entails the administration of painkillers, sedatives, blood pressure stabilizers, and supports for the frog, the fleshy portion of the bottom of the foot.


What happens if a horse eats a walnut?

Ingesting and inhaling walnuts induces digestive problems in horses, according to ASPCA. Horse beddings laid out of black walnut wood and shavings are poisonous to horses. 

If your horse ends up eating a walnut, it might get an allergic reaction as well as laminitis and colic. However, simply eating one walnut might not induce depression and fluid buildup. It will create digestion issues, nonetheless. 

There is a mold that the husk of the nut retains, which is behind liver cancer in many cases. 

So your horse may also contract cancer if you are not careful about what is happening in its stomach. Due to the highly toxic tree, many animals suffer the same fate as horses.

Related: (Answered) Do Alfalfa Pellets Need To Be Soaked?

Does walnut sawdust kill horses?

Black walnut sawdust or shavings are indeed toxic to horses. 

Horses will suffer from laminitis; if you leave it untreated, the horse could die. The feet of the horse will hurt if it has laminitis, and you will find it unable to walk, or even if it does, it will be as if the horse is walking over thorns. In worse cases, the horse will be sluggish and lie down for an extended period. 

The lower legs will start swelling, and other previously mentioned symptoms will appear. The horse could die from sickness, and the vet would have to amputate the infected leg at one point.

Final words…….

From the research that has been conducted, it appears that walnut trees are toxic to horses. While there is still some debate on the matter, the consensus is that walnut trees should be avoided if you have horses.

If you have horses and walnut trees on your property, it is vital to ensure that your horses do not come into contact with the tree or its leaves. There are various ways to do this, so speak with your veterinarian or a qualified equine nutritionist to find out what is best for your situation.

Zunnun Ahmed

We are a group of horse enthusiasts. We want to provide information and tips to help others learn more about horses, how to care for them, and how to enjoy them.

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