What is Acorn Poisoning?
An uncommon condition in horses, acorn poisoning is caused by consuming significant quantities of acorns, oak leaves or bark. Most species of oak in Europe and North America can cause toxicity in horses. While consuming a few acorns should not be an issue for most horses, it is not known how many acorns would lead to toxicity in a horse. There are multiple factors that lead to the level of concentration of toxicity being varied; for example, the tannins in oak acorns, bark, leaves and twigs will be different based on the season and may change from one year to the next. Toxicity is usually greater in less mature acorns, buds, and branches than in those that are more mature, meaning that toxicity would be worse in the spring. It is important to note that sensitivity to the toxins in acorns will vary by individual animal.
Should your horse have enough feed, he will usually avoid acorns, as they can taste bitter. Some horses will find the acorn nuts appealing and will look for them specifically, rejecting other feed options.
Acorn poisoning in horses, while infrequent, can occur when a horse ingests a large number of acorns, oak leaves or bark, leading to a variety of symptoms due to toxicity.
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Symptoms of Acorn Poisoning in Horses
A variety of symptoms may be observed in horses that are experiencing acorn poisoning. Symptoms will typically be noticed a few days after ingestion. Symptoms include:
- Poor hair coat
- Loss of appetite and weight loss
- Frequent urination and blood in urine
- Increased thirst
- Pale mucous membranes
- Slow or irregular heart rate
- Emaciated appearance
- Mouth ulcers
- Abdominal pain
- Kidney failure
- Organ hemorrhage
- Scent of ammonia on their breath
- Pain when defecating
- Clear discharge coming from eyes or nose
Should the liver and kidneys of the horse be impacted, the horse will die without treatment. Pregnant horses that ingest acorns during their second trimester may experience the loss of their pregnancy or their foal may be born with birth defects.
Toxicity may occur when your horse has ingested acorns, oak leaves, or bark. The level of toxicity will vary based on a number of factors to include:
- Time of year
- Whether acorns, oak leaves or bark (or all of these) were consumed
- Age of items that were consumed
Causes of Acorn Poisoning in Horses
Should your horse consume a significant quantity of acorns, oak leaves or bark, he may experience poisoning as a result of the sharp tannic acid in the oak material entering his tissues and eliminating his fluids, leading to kidney and liver damage. The tannin may also get in the way of how your horse’s body uses protein.
Diagnosis of Acorn Poisoning in Horses
Diagnosing acorn poisoning is challenging. In some cases, horses may be known to eat acorns, and that information can aid in diagnosis. Should you notice changes in your horse or any of the symptoms listed above, you will want to contact your veterinarian. Your horse will be fully examined and the veterinarian will ask questions regarding the symptoms you have noticed, when you have noticed them, and any changes you have seen. You will also be asked for information on your horse’s medical history. Your veterinarian may recommend keeping an eye on your horse’s excrement to see if there are any signs of digested acorn material, should he think that your horse is experiencing acorn poisoning.
Treatment of Acorn Poisoning in Horses
Should your horse be experiencing acorn poisoning, your veterinarian will focus on options for supportive treatment, as there is not a known cure.
Often, horses that are experiencing acorn poisoning will experience dehydration. Intravenous fluids may be recommended to keep his circulatory system going, as well as to prevent shock and kidney failure.
Activated charcoal is an antidote for acorn poisoning and is most helpful right after your horse has consumed the toxic material. Charcoal will take in the tannins that reside in your horse’s system and lead to their being eliminated.
A few options are helpful if started early in the disease process; these include calcium hydroxide and mineral oil, sodium sulfate or magnesium sulfate. These will help your horse with eliminating feces. If it is not possible to keep acorns or oak leaves from your horse, a supplement that includes 10-15% calcium hydroxide may help to prevent poisoning.
Should your horse be experiencing colic (which can happen) a painkiller may be recommended in order to help him feel more comfortable.
Recovery of Acorn Poisoning in Horses
To help keep your horse from experiencing acorn poisoning it is important to keep his pasture well-maintained and provide him with an appropriate amount of hay and grass. Many horses are able to ingest a small number of acorns with no issues. A horse can develop a taste for acorns and ultimately an addiction. For this reason, you will want to remove oak leaves, branches, and acorns from areas where grazing animals can access them.
Should your horse experience acorn poisoning, recovery will typically happen within 60 days, though if kidney damage is severe recovery may not be possible.