Colitis in Horses

colitis in horses

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Your beloved horse is having uncontrolled diarrhea and obvious discomfort. You’re concerned about dehydration and maybe you’ve heard colitis can harm a horse so badly death is a possible outcome.

What should you do? This article will point you in the right direction.

What is Colitis?

Equine colitis is a condition that occurs when the lining of the lower part of the digestive tract – either the colon or cecum or both – of a horse becomes inflamed. The condition has many causes, and always requires the oversight of a veterinarian.

How to Tell if a Horse has Colitis

Colitis commonly causes diarrhea in horses. The diarrhea can be stools that range from poorly formed (they look like cow poop) to completely liquid.

Diarrhea: Diarrhea due to colitis can have blood in it, and is commonly much more foul-smelling than usual.

Colic: A horse with colitis will often exhibit signs of colic. Colic indicates a problem with the horse’s digestive system that leads to pain and discomfort in the abdomen. Horses with colic will pay attention to their sides, biting or kicking them, and may roll more than usual to attempt to relieve the pain. You may see poor appetite or your horse drinking more or less than usual.

Swelling: Colitis can cause ventral edema, which means a swelling of the underbelly or lower parts of the legs.

Tiredness: Also called lethargy. Colitis can cause a horse to be dehydrated, feel poorly, and not eat will. All of this leads to a lack of energy, which means your horse is unable or unwilling to engage in normal activities.

All of these signs can suggest a diagnosis of colitis, but can also be due to other problems.

Diagnosing Colitis in Horses

Colitis should never be diagnosed by anyone other than a licensed professional. Colitis can be extremely serious and even lethal in horses, and can only be treated if supportive care is quickly given and the underlying cause is identified and treated quickly.

If your horse is showing signs of colitis, call your veterinarian immediately.

Your veterinarian will administer tests to determine the cause of the signs you’re seeing and test for colitis. Your veterinarian may use the following techniques:

  • Physical examination
  • Ultrasound
  • Testing of the poop to look for blood, bacteria, sand, or parasites
  • Blood work
  • Amniocentesis (pulling collected fluid from the horse’s belly)
  • Biopsy (collecting tissues with a needle to test and see what’s wrong)

Causes of Colitis in Horses

Equine colitis is caused by damage to your horse’s lower digestive tract. Unfortunately, a lot of things can cause damage to a horse’s colon/cecum! Here’s a list of the known causes:

  • Bacterial Infection: This is an infection of the colon and/or cecum by bacteria including Salmonella, Clostridium difficile, Clostridium perfringens, Lawsonia intracellularis, ‌Escherichia coli, or ‌Neorickettsia risticii, which causes Potomac Horse Fever
  • Viruses: Like bacteria, viruses can infect a horses gut and cause colitis. Rotavirus and equine coronavirus can cause colitis.
  • Parasites: Strongyles are a parasite that causes colitis. Merck & Co. state “[Strongyles] burrows into the walls of arteries that supply blood to the small and large intestines, which can cause colic, tissue death, impaired intestinal function, twisting of the intestine, intussusception, bleeding and even intestinal rupture.”
  • Antibiotics: Like in humans, using antibiotics that kill the healthy bacteria in a horse’s gut can lead to problems, including colitis.
  • Sand Impaction: If a horse eats too much sand, it can get into their lower gut and cause colitis and other problems.
  • NSAIDs: Non-steroidal anti-inflammatories can cause harm in many animals, including horses. NSAIDs can cause a specific type of colitis called right dorsal colitis in horses.

Treating Colitis in Horses

Treating colitis involves supporting the horse against the damage the colitis does and treating the underlying cause.

Supporting the horse involves rehydration, ensuring that the horse has the appropriate electrolytes, and ensuring any nutritional deficits or overages are corrected.

Correcting the underlying cause means treating any parasitical, viral, or bacterial infections, correcting any diet issues causing colitis, and withdrawing any NSAIDs that might be causing the issue. Your veterinarian may identify these and other specific causes that need treating – colitis can be very complex!

How to Prevent Colitis in Horses

Preventing colitis means ensuring your horse have everything it needs to maintain a healthy gut:

  • Allow free access to forage. The simple carbohydrates in some horse diets lead to bacterial imbalance in the gut that can cause colitis.
  • Feed more oats than other grains.
  • Vaccinate against Potomac Horse Fever. This particular cause of colitis has a vaccine.
  • Maintain good hydration. Dehydration can cause horses to undergo stress and disrupt the balance of healthy bacteria in their gut.
  • Use plants that contain roughage as feed over feeds with simple carbohydrates. Hay, grass, and beet pulp are good choices.
  • Feed the horse smaller meals more often. Large meals separated by a lot of time can lead to impaction and gut imbalance.
  • Change feeding regimen slowly and gradually. Just like a dog’s food should be changed gradually over time, a horse’s diet should be changed gradually, not all at once.
  • Find Alternatives to NSAIDs. If your horse is suffering from colitis , especially right dorsal colitis (also called NSAID toxicosis), ask your veterinarian if it’s possible to use a different NSAID or lower dose of NSAID. According to the authors of Cannabis Therapy in Veterinary Medicine, CBD products can be used to support pain therapy and reduce or eliminate the use of NSAIDs for certain conditions in horses. See our article on CBD for Horses for more detail.
  • Help the horse avoid stress. Stress can lead to imbalance in the gut and promote inflammation in horses. Making sure to calm your horse during stressful situations and ensure that stressful situations are minimized can help. CBD has also been used to help support horses with stress and anxiety.

Supporting a Horse With Colitis

Before we talk about how you can help your horse, do not try to treat colitis on your own without the help of a veterinarian. If you believe your horse has signs that point to colitis, it’s critical to get help immediately. Colitis is a serious condition!

In supporting your horse, follow your vet’s recommendations regarding medication or other therapy specific to your horse. Work on the prevention options already mentioned.

Lastly, ask your veterinarian if trying CBD would be a good option. CBD works on the endocannabinoid system to reduce and relieve inflammation, decrease stress, and can reduce the needed dose of NSAIDs to provide adequate relief. Incorporating CBD in a holistic treatment plan can help ease equine colitis.

“Colitis in horses is another painful and significant disease process which seems to be highly responsive to CBD therapy. Equine clinicians should consider cannabinoid therapy for cases of chronic colitis or inflammatory bowel disease, especially in those patients who cannot tolerate systemic corticosteroid therapy. Based on a review of cannabinoids’ role in colitis in humans and mice, there is strong evidence to show that phytocannabinoids can decrease inflammation within the gastrointestinal tract and lead to improvement in outcomes.” - Cannabis Therapy in Veterinary Medicine

If your horse has right dorsal colitis, on recovery ask your veterinarian if CBD can be used to decrease or eliminate the need for NSAIDs in your horse. CBD is not associated with colitis (or any other health problems) in horses.


Practicing sensible preventive care, taking your horse to the vet immediately on seeing signs, and treating your horse promptly are critical to their success in regaining their health after colitis.