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What Causes a Horse to Founder and Can They Recover From It?

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We were told our horse might have foundered. Our grandson saw the concern on our faces and immediately asked, what is founder, and why are you so concerned?

Founder is basically when a horse’s hoof becomes so swollen that it is painful to stand on it. It’s most commonly caused by laminitis, an inflammation of the lamens (the thin layers of tissue connecting the hoof wall to the coffin bone).

There are several things that can cause laminitis, such as eating too much grain or sugar, overworking a horse, or even dehydration. If left untreated, founder can lead to death. But thankfully, with early diagnosis and veterinary care, most horses make a full recovery. This article explores what causes founder in horses and how it can be treated.

Diagram of a horses hoof,


What is founder in a horse?

Founder is a condition that affects horses’ feet, causing discomfort and difficulty in movement, and is one of the most common causes of lameness in horses. It involves damage to the area between your horse’s hoof wall and coffin bone.

It occurs when the laminae tissues become inflamed or damaged, and they are unable to support the coffin bone, causing it to rotate and “sink.” The laminae are the layers of tissue that attach the hoof to the bone, and the coffin bone is the bottommost bone within a horse’s leg, similar to the tip of a human finger.

Horses with founder typically show signs of distress in their movements, but luckily there are things you can do about it. However, it is a serious condition that can lead to permanent lameness in horses, so it is important to seek veterinary care as soon as possible.

Clinical and radiographical examinations of the hooves by a veterinarian are needed to confirm a diagnosis of founder. The sooner that you get professional help, the less likely your horse’s condition will worsen and become irreversible – but there are cases where treatment cannot help.

Laminitis and founder are two of the biggest concerns for horse owners. Various factors can cause both, but the most common is diet. Horses on lush pasture or high-grain diets are most susceptible to laminitis and founder.

The best way to prevent laminitis and founder is to keep your horse at a healthy weight. This means feeding them a balanced diet and providing plenty of exercise. If your horse is already overweight, work with your vet to create a weight loss plan that will be safe and effective. Founder can be a debilitating condition, so it’s important to do everything possible to prevent it.

Acute laminitis

Acute laminitis is a sudden onset of pain and inflammation in the laminae, while founder is an ongoing condition involving movement of the coffin bone. The two are often confused, but knowing the difference is important so you can properly treat your horse.

Acute laminitis comes on quickly and is usually accompanied by swelling in the hooves and lameness. Founder, on the other hand, is a chronic condition that develops over time and results in the sinking or rotation of the coffin bone.

Founder is more difficult to treat and often requires long-term management. If you suspect your horse has either condition, it’s important to contact a veterinarian immediately. The saying “no hoof, no horse” is as accurate today as it ever was.

Picture of a horse standing still in a pasture which is an indicator of founder.

What causes founder?

Horse founder is a serious and often deadly condition that many things can cause. Here are the top reasons horses founder:

  • Improper feeding

Feeding a diet that is too high in sugar or starch can cause horses to founder. This happens when the digestive system becomes overwhelmed by a large amount of sugary food, and the blood flow to the horse’s feet is reduced.

  • Overeating

Make sure your horse is at a healthy weight. An overweight horse is much more likely to founder than one who is in good shape. Horses have an instinctive need to chew.

If they are given too much grain or offered unfettered access to silage, they will eat it all. Overeating itself can do it, but so can weight gain.

When a horse is overweight, it places more strain on its joints and ligaments, is less likely to get enough exercise, and develops diabetes, increasing the risk of developing laminitis.

Horses only need grass and hay to live healthily. Overfeeding and feeding a horse incorrectly is more harmful than underfeeding your animal. For example, grain is a good energy source for cold days and when the horse will exert itself.

However, too much grain is harmful, and a grain-only diet is not the right choice. Having some hay mixed with the grain is much better for your horse. An even better idea is to put forage into a hay net, so the horse eats it slowly.

Some grass, when eaten early in the morning, can also lead to laminitis and founder. This is particularly true if the grass is from a new source. If you want to learn more about the types of grass horses eat, you should read Grass For Horses: Why it’s Essential and the Different Types.

Horses need their feed changed very slowly, and it’s not just to prevent founder. Too swift a change, and the horse could develop colic.

If you’re a new horse owner, spend some time reading about equine diets and talking to veterinarians and experienced horsemen. Most should advise you to supplement your horse’s hay or grass if it requires extra energy.

  • Insulin resistance: 

Horses are mammals and, like other mammals, can develop something similar to what we humans call diabetes. When insulin can’t turn food into glucose, the muscles suffer. When that happens, the horse is liable to develop laminitis.

This is more common in senior horses than in younger ones. If your horse is insulin-resistant, take preemptive measures to reduce the chance it develops laminitis, such as eliminating grains and sweet feed from its diet and exercising the animal as much as possible.

  • Breed

Some breeds of horses and ponies are more prone to founder than others. A two-year study done in the U.K. showed that some of the native breeds were more likely to founder than other breeds. Genetics can play a role in deciding what the horse will do.

Below is a YouTube video of a horse with founder.

  • Percussion

Avoid exercising your horse on hard surfaces for extended periods of time. Provide a soft surface to run and play on instead. There are two ways to look at percussion injuries. One of them is riding.

Riding a horse hard can do lasting damage to the hoof, including causing both acute and chronic laminitis. That doesn’t mean a horse can’t be ridden hard; just that care has to be taken.

The farrier needs to know what kind of riding the horse will be doing. The shoes he or she attaches will differ depending on the horse’s needs. It’s also essential to have an excellent farrier. They can spot the beginnings of laminitis before you do.

The second has to do with shoeing. No matter how good the farrier is, some horses will have some laminitis after shoeing. This is especially true if the length of time between visits is more than eight weeks.

A horse’s hoof is like our fingernails, in a way. They are continually growing. To keep the horse comfortable and provide the stability it needs, they need to be trimmed regularly by someone who knows what they are doing.

For those who believe in a horse going “barefoot,” this is even more important. Horseshoes are used to protect the hoof, much like our shoes protect our feet. Without regular trims, it can cause the horse to stand at an odd angle, leading to… laminitis.

Picture of a two year old horse in training
  • Medications

Steroids and nonsteroidal anti-inflammatory drugs can, over time, cause laminitis. One would think it would have the opposite effect, but overuse is definitely a cause.

The reaction to steroids is even more pronounced when horses are fed a high-carbohydrate diet. Scientists found that horses administered steroids after eating a high carbohydrate diet were much more likely to develop laminitis.

  • Colic surgery

Founder only happens in one to two percent of the surgeries, although it does happen. However, administering low‐molecular‐weight heparin (LMWH), post-colic surgery has proven to be effective in preventing laminitis.

  • Black walnut exposure

If you’ve looked around a black walnut tree, you may have noticed poor soil. That’s because the tree, bark, and leaves contain a toxin. Horses are extraordinarily sensitive to this toxin.

If they eat it or it’s part of the shavings in their stalls, they are at risk of developing laminitis. Prolonged exposure will result in chronic laminitis, aka founder. The amount doesn’t have to be great to do this. As little as twenty percent of black walnut shavings can cause this problem.

  • Pregnancy

Both the added weight of the foal and the hormones released during pregnancy can result in laminitis. It may also relate to general biological changes that sometimes cause pregnant horses to be insulin-resistant and thus prone to develop laminitis.

The Symptoms of Founder in Horses

Founder is a condition that can strike at any time and cause permanent damage. So it’s essential to be able to spot the signs of founder early and get your horse treated.

The first sign is usually a change in gait that may or may not be accompanied by pain; it can also include swelling around the foot and ankle joints. Other symptoms of founder are a noticeable pulse in the foot, a reluctance to move, and standing with its front legs extended.

Some horses with founder alternate weight from leg to leg or display obvious signs of pain. In severe cases, you can see a difference in the sole of a horse’s foot; sometimes, the pedal bone is noticeable.

It is important for any owner with a horse with lameness issues to ensure they seek veterinary attention immediately before things get worse.

Picture of a horses lower legs.

So, what can I do to prevent founder?

Some of the answers are rather obvious. Keep the horses away from black walnut, including shavings, trees, or wood fences made from the tree. Watch the horse’s feed, keep an eye out for weight problems, and ensure it has its hooves trimmed regularly.

Use a grazing muzzle if your horse is on rich, lush pastures. You can click on the following link to read a helpful article about grazing muzzles. In the article, I cover the different types of grazing muzzles and when they should be used.

Below is a YouTube video with tips on how to prevent laminitis.

Some are harder to cope with. When it comes to trimming and shoeing, please work with your farrier and your large animal vet to balance its feet. It isn’t necessary to avoid all medications; just make sure they aren’t overused.

Horses can recover from founder.

Acute laminitis can be treated. It may get better; it may not. It depends on the cause, the severity, and the horse. Typically a horse with acute laminitis is given stall rest and an anti-inflammatory drug like DMSO.

DMSO is a chemical compound that is often used to treat inflammation and pain. It is most commonly used topically but can also be administered orally or intravenously. In the case of laminitis, DMSO is often administered in the early stages to arrest inflammation in the soft tissues of the hooves.

While DMSO is generally safe, there are some potential side effects; however, when used properly, DMSO can be an effective way to treat founder. I recently discussed with a trainer about using DMSO to treat horse ailments and wrote an article about the medication I think is helpful for people interested in using it.

Chronic laminitis may be treated. Once again, it depends on the cause and the horse. A lot of times, when chronic laminitis is diagnosed, the subject of euthanasia comes up. The question of quality of life over quantity comes into play.

Chronic laminitis slowly worsens until the horse can no longer stand because of intense pain. Often the condition will progress to the point that the coffin bone penetrates the sole of the animal’s foot.

When this happens, little can be done to save the horse; the most humane choice is likely to put your companion out of its misery.

However, these decisions are best made after consultation with your vet and farrier. It isn’t an easy choice to make, no matter what sort of furry loved one we have.


Can grass cause a horse to founder?

Yes, grass can cause a horse to founder through excess sugar in the diet. When horses graze on pasture, they eat mostly carbohydrates (sugars) and very little protein. This type of diet is high in nonstructural carbohydrates (NSC) and can result in “grass founder.”

What’s the difference between laminitis and founder?

Laminitis is an inflammation of the sensitive laminae within the hoof. Founder is a rotational deformity (typically of the hindlimbs) in horses that are typically caused by laminitis. The terms are often used interchangeably.