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Can Horses Eat Acorns? What You Need to Know!

Oliver Jones

If you are lucky enough to have a beautiful oak tree in your horse paddock, you know how many thousands of acorns that a tree can drop during the autumn months. Of course, with all these acorns littered on the floor, your horse may try and eat a few. But are acorns safe for horses?

In small quantities, acorns do not pose much of a threat to horses, but in large enough quantities, they may cause serious health issues. It may not be feasible to remove either your horse or the tree from your paddock, and it’s almost impossible to remove all the fallen acorns from a large tree. This will naturally get some horse owners worried.

In this article, we’ll look at the potential threats posed to your horse by acorns and what you can do to keep your horse safe.

divider-horseAre acorns dangerous to horses?

feeds-a-horse_Tereza-Tsyaulouskaya_shutterstock
Credit: Tereza Tsyaulousaya, Shutterstock

Acorns are potentially toxic to horses, and although in small quantities, your horse will most likely be fine, in larger amounts, they can be potentially fatal, causing issues like colic, diarrhea, and even kidney failure. That said, although acorn poisoning has been widely documented in cattle, it is fairly rare in horses because they don’t generally enjoy the taste of acorns.

Acorn poisoning can be caused not only by eating acorns but also by eating the leaves, bark, and fresh shoots of oak trees. Unfortunately, it’s exceedingly difficult to know just how many acorns are fatal to horses, as the level of concentration of toxicity is determined by several factors: The tannins in the acorns, bark, buds, and leaves are different depending on the season and may even change from one year to the next. Additionally, less mature acorns are usually more toxic, and an individual horse’s sensitivity to the toxins can vary too, further complicating the matter. For these reasons, it’s best to keep your horses away from acorns and oak trees as much as possible.


Symptoms of acorn poisoning

The gallotannins present in the oak leaves and acorns can cause damage to your horse’s stomach, intestinal lining, and kidneys, leading to colic-like symptoms and blood in their urine and feces.

While acorn poisoning is rare in horses, it can still happen, and you should be aware of the associated symptoms, especially if your horses have access to an oak tree.

These symptoms usually occur a day or two after ingesting acorns and include:
  • Dehydration
  • Loss of appetite
  • Increased urination
  • Constipation or diarrhea
  • Abdominal pain or colic
  • Discharge from the eyes and nose

The more acute the symptoms that your horse displays, the more danger they’re in. If your horse’s symptoms come gradually over a few days rather than hours, they will most likely be fine.

Unless your horse has been in a paddock with an acorn tree and you are sure they’ve been eating parts of the tree, it’s difficult to diagnose acorn poisoning. Whether you suspect that your horse has eaten acorns or not, if you notice any of the listed symptoms, you should contact a vet immediately.

acorn outdoor
Image Credit: TimHill, Pixabay

How to stop your horse from eating acorns

Luckily, most horses are not inclined to eat acorns or any other part of an oak tree, especially if they have enough forage or feed. That said, the fresh shoots may be tempting during the spring, and your horse may eat acorns if they have limited quantities of other foods. Additionally, young horses are curious animals and may try out a few acorns and develop a taste for them!

While most horses will not eat acorns, there may be a perfect storm of factors that could lead to poisoning. If you have several horses together in a paddock competing for hay, and there are a large number of acorns on the floor and fresh shoots on the oak tree, this scenario could tempt your horse and potentially result in acorn poisoning.

The best method is prevention, and it’s wise to try and make sure your horses are in a paddock without any oak trees at all. If you do have oak trees in your paddock, you may need to consider building a fence around them so your horses cannot access them and remove any low-hanging or damaged branches. Also, make sure your horses have plenty of food, so they are not tempted to snack on the oak tree and acorns.

Treatment of acorn poisoning

There is no known cure for acorn poisoning, so your vet will likely concentrate on the supportive treatment of symptoms. For example, dehydration will likely be treated with intravenous fluid to prevent organ damage.

Activated charcoal is one of the first things that you should give your horse if you suspect that they’ve ingested acorns, as it will help soak up the toxic tannins before they do any serious damage and carry them safely out of your horse’s digestive system.

Shire and Clydesdale Horses_Shutterstock_R.M.T
Image Credit: R.M.T, Shutterstock

horse shoe dividerFinal thoughts

Acorns and the leaves, bark, and shoots of oak trees are toxic to horses, and even though they are unlikely to do any damage in small amounts, they should be kept as far away from your horse as possible. If your horse does manage to ingest any of these and is showing symptoms, it’s vital to get your horse to a vet as quickly as possible, as organ damage and even death are real possibilities.

That said, acorn poisoning is rare in horses, even in areas with loads of oak trees, as they generally do not enjoy the taste of acorns or the oak tree. Making sure your horse has enough fresh hay and forage should be enough to prevent them from eating acorns at all!

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Featured Image Credit: jggrz, Pixabay

Oliver Jones

Oliver (Ollie) Jones - A zoologist and freelance writer living in South Australia with his partner Alex, their dog Pepper, and their cat Steve (who declined to be pictured). Ollie, originally from the USA, holds his master's degree in wildlife biology and moved to Australia to pursue his career and passion but has found a new love for working online and writing about animals of all types.