8 of The Most Common Horse Diseases

Did you know the average horse will live well into his 20s, and many will even enter their 30s? But—like humans—a horse’s longevity depends on how well his health is managed. The good news is there’s a lot you can do to keep your equine companion healthy into his senior years. A good routine of feeding, exercise, and veterinary care is a start. But how familiar are you with the most common horse diseases? Do you know how to spot the early signs of those conditions? In this post, we’ll discuss common horse diseases every owner should be familiar with. We’ll tell you the signs and symptoms to look for, as well as treatment options if your horse falls ill.

Read on to learn more—your horse’s health depends on it!

1. Colic

Just like human babies can get “colicky” with an upset stomach, horses are also prone to digestive ailments. Equine colic can range from mild to severe enough to require surgery (or euthanasia). Why is colic such a concern in horses? Because unlike most animals, horses can’t vomit. If they ingest something that makes them ill or impacts their gut, they either have to pass it or have it surgically removed.

Signs of colic include:

-Biting at or kicking towards their belly

-Lying down with refusal to get up

-Rolling on the ground

-Anxiety and agitation

-Lack of appetite

-No defecation

-Elevated pulse rate

Horses can get colic for a variety of reasons. Spasmodic colic is the result of gas buildup in the intestines, while impact colic occurs when food (or something else swallowed) gets “stuck” in the gut. Most cases of colic occur suddenly and without warning. If your horse shows any of these signs, try to keep him on his feet and immediately call your veterinarian. Left untreated, colic can be fatal to horses.

2. Laminitis (Founder)

Perhaps one of the most dreaded horse diseases, laminitis can leave your horse permanently lame (at best) or requiring euthanasia. Laminitis occurs from inflammation of the laminae structures within the hoof. In severe cases, the coffin bone inside the hoof detaches from the hoof wall and rotates downward, puncturing the sole of the hoof. It’s often the result of a grain binge (if the horse breaks into the feed room, for example) or overeating lush grass. It can also result from excessive work on hard surfaces or prolonged high fever.

Signs of laminitis include:


-Heat in the hooves and lower legs

-Hesitant gait or reluctance to move (“walking on eggshells”)

-Pain in the toe region from applied pressure with hoof testers

-“Sawhorse” stance with outstretched forelegs and weight shifted to hindquarters

If your horse accidentally goes on a grain binge, do not wait for symptoms of founder to develop. Immediately call your veterinarian. Treatment for laminitis can include corrective shoeing, a modified diet, and a slow return to activity. Severe cases (when the coffin bone detaches and drops) are almost always fatal.

3. Degenerative Joint Disease (Osteoarthritis)

Humans aren’t the only animals prone to joint disorders like arthritis. Horses can also develop osteoarthritis, more commonly known as degenerative joint disease (DJD). Arthritis occurs gradually from the wearing away of cartilage between the bones of a joint. Over time, the area becomes stiff and inflamed. The most common areas horses develop arthritis are in the lower legs, stifle, and back.

Signs of equine arthritis include:

-Swelling and heat around a joint


-Stiffness or lameness

-Reduced range of motion

The harder your horse works over his lifetime, the greater his chances of developing arthritis later in life. Minimize the risk by working on soft surfaces, warming up and cooling down properly, and keeping your horse at a healthy weight. If your horse does develop arthritis, there are different ways to manage the condition and reduce his discomfort. Many owners have terrific success using CBD oil for horses with arthritis. Other treatment options include light exercise, oral supplements, or injections into the affected joint.

4. West Nile Virus

This mosquito-borne virus originated in Africa and made its first appearance in North America in 1999. In horses, West Nile Virus causes infection and inflammation in the brain and spinal cord. The good news is that the majority of horses bitten by a carrying mosquito will not develop symptoms.

For those that do, common symptoms include:

-Weakness in hind limbs

-Loss of appetite



-Difficulty swallowing

-Vision impairment



-Muscle twitching

There’s no specific treatment for West Nile Virus other than managing the symptoms and letting the disease run its course. The best solution is prevention through an annual West Nile Virus vaccine. You can also reduce the mosquito population around the barn and pastures by eliminating standing water.

5. Azoturia (Tying Up)

This horse disease has many names, including equine rhabdomyolysis syndrome (ERS), tying up, or Monday morning disease. Whatever name you give it, it describes a severe disturbance in your horse’s typical muscle function. It’s generally the result of overexertion without properly cooling down. It can also occur at the beginning of a workout too soon after a large meal.

Signs of azoturia include:

-Sudden, severe muscle cramps

-Acute distress

-Unwillingness to move

-Profuse sweating

-Elevated pulse and respiratory rate

-Dark brown or red urine

A horse with a mild case of “tying up” may become stiff and shorten his stride. In severe cases, he may become completely immobile due to muscle seizure. If you suspect azoturia, immediately get off your horse, keep him still, and call your vet. Typical treatment involves muscle relaxers, anti-inflammatories, and massage. Unlike some of the other horse diseases we’ve discussed so far, tying up is rarely fatal. Most horses will make a full recovery within 6-8 weeks.

6. Strangles 

Do you remember getting strep throat when you were a kid? There’s an equine version of that disease too, and it’s appropriately named “strangles.” Strangles is caused by the Streptococcus equi bacteria. It’s extremely contagious and is one of the most widely diagnosed horse diseases around the world.

Signs of strangles include:

-Swollen, enlarged lymph nodes between the jawbones

-High fever

-Nasal discharge

-Inability to lower the head

In some cases, the swollen lymph nodes may abscess and require draining by your veterinarian. A course of antibiotics also helps to control the bacterial infection. Although the disease is unsettling for the owner, it’s rarely fatal for the horse. Most recover within a few weeks with little complication. The problem with strangles is once one horse is affected, it quickly spreads to others. If there’s an outbreak on your farm, you should not move any horses off the property (or introduce new ones) until well after the last symptoms have resolved.

7. Eastern Equine Encephalitis (EEE)

Another mosquito-borne illness common in the US and Caribbean is eastern equine encephalitis. Most reported cases are east of the Mississippi River. Although the disease also occurs in humans, there’s no evidence that it can pass from horses to humans (or vice versa).

Signs of this disease include:

-Depression or drowsiness

-Lack of appetite

-High fever

-Tremors or convulsions in the face and neck

-Facial paralysis

-Head tilt

-Progressive weakness or paralysis Horses that develop EEE receive a grim prognosis. The mortality rate in affected horses is 75%-95% within 3 days of showing symptoms. To prevent this terrible horse disease, keep your horse’s vaccinations up-to-date with yearly boosters against EEE.

8. Worms & Parasites

Horses, like other animals that graze and spend most of their time outside, are prone to picking up parasites.

The most common ones include:








All horses carry at least some internal worms, which is why a regular deworming schedule is so important. Your schedule will depend on the local climate and prevalence of worms, but most vets recommend deworming every 6-12 weeks. You can also reduce their chances of picking up worms by keeping their stalls and bedding clean. Avoid feeding hay or grain in areas where there’s a lot of manure. What about external parasites? If your horse is constantly scratching against posts or starts losing hair, he may have picked up an external “traveler.” Pick up an anti-fungal or anti-parasite shampoo and give him a long, thorough bath. You should also keep up with the regular deworming routine mentioned earlier.

The Most Common Horse Diseases: Now You Know

So, how many of these horse diseases were you already familiar with? Were any of them new to you? While some of these diseases appear suddenly, others are more subtle. This makes early detection crucial to maintaining your horse’s health. Whatever you do, keep educating yourself about different horse issues and diseases. You never know when that knowledge could help to save a life! Did you find this article useful? Check out our other recent blogs for more great information.

Published by Larry Fire

I write an eclectic pop culture blog called THE FIRE WIRE that features articles about books, comics, music, movies, television, gadgets, posters, toys & more!

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