Why Can’t a Horse Live With Three Legs or Fix a Broken One?

Last updated: December 6, 2022

By: Miles HenryFact Checked

My friend euthanized his horse after its leg broke during a race. We knew the horse well, and it was a favorite of my grandson’s. He immediately asked why they couldn’t fix his broken leg or let the horse live with three legs.

Horses can’t live with three legs because their massive weight needs to be distributed evenly over four legs, and they can’t get up after lying down. Horses that lose a leg face a wide range of health problems, and some are fatal. Most leg breaks can’t be fixed sufficiently to hold a horse’s weight.

If you own horses or have been around them much, you’ve likely noticed they often put their weight on three legs when relaxed. Does this prove they can survive on three legs? I think not.

Horses with three legs face challenges.

Horses can’t survive with three legs. Yes, they relax and shift their weight onto just three legs; however, they frequently shift their weight and use the fourth leg to bear some burden.

Could they perform the maneuver without a fourth leg? I think not; their weight is too significant of an obstacle to overcome. Horses with three legs face insurmountable obstacles necessary to survive.

Horses need four legs to rise.

A three-legged horse that lays down or falls can’t stand back up on its own, and when a horse can’t stand on its own, there’s at risk of severe injury and death.

And even with your help, it’s unlikely the horse rises because an average-sized horse weighs over 1,000 pounds. The only way a horse could get up with three legs would be with a machine or mechanical device’s assistance, like a wench.

Horses that lay down for extended periods develop adverse health conditions.

The enormous size of these animals requires they stand periodically to avoid damaging tissue and organs. Restriction of blood flow, crushing of nerves and muscles are some of the damages a horse suffers when they lay on the ground for too long.

Blood flow is restricted.

When horses are lying down, their blood flow is restricted. This restriction causes damage, but also the reintroduction of blood flow damages organs and cells.

A restriction in blood supply creates a shortage of oxygen that is needed to keep tissue alive. When tissues die, organs are damaged, and the death of an animal can occur.

And after blood flow and oxygen are reintroduced, there can also be damage caused to cells and, ultimately, organs. This phenomenon is called reperfusion injury.

Muscles and nerves are damaged.

Laying for extended periods also negatively affects a horse’s muscles and nerves. This is a critical concern for a horse that undergoes surgery. If a horse is sedated for a long time, the animal must be moved to avoid compression injuries.

The body weight of a horse, when it’s prone, crushes nerves and muscles on its underside. A horse with three legs would spend too much time on the ground to survive.

Lungs are adversely affected.

Horses that lay for a long time begin crushing their nerves and muscles, but also the blood that should be circulating throughout their body begins to pool.

The blood flows to the lowest and most accessible spots to travel, often the lung closest to the ground. A horse with three legs would have a poor life quality and likely die a slow, painful death.

The remaining legs suffer.

A horse often bears most of its weight on three legs when resting; however, they alternate the relaxed leg. When a horse only has three legs, the limbs never get a break and are under an unusual burden.

A horse that loses one leg risks damaging the other legs because they carry the animal’s entire weight. The remaining legs are prone to circulatory problems, laminitis, and joint diseases.

Prosthetic legs for horses

On rare occasions, horses have been fitted with a prosthetic leg. One such animal was a pony named “Molly” that lost a leg because of a dog attack during hurricane Katrina.

She was an exceptional pony with the correct temperament, size, and injury location for the prosthesis to be successful. However, this rarely occurs, but “Molly” does prove that artificial limbs can be an option for horses with three legs.

Prosthetic limbs for equines are typically made of carbon graphite and titanium. As you probably can guess, they’re costly and only work in limited situations.

It’s difficult to fix a broken leg

There are simple bone breaks that can be successfully treated with rest and surgery. However, severe fractures are challenging to treat in horses successfully because it’s hard to keep a horse still during recovery, infections, and the animal’s weight.

Immobilization

When horses break their leg, they have to keep weight off the injured limb and keep it stabilized; this is extremely difficult. They can’t lay down for extended periods for the reasons described above, and their instinct is to move.

Horses are prey animals and survived through the centuries because they instinctively move around. Keeping them immobile is difficult, and many horses refuse and act out reinjuring themselves.

Another major issue that arises when horses can’t move around, is laminitis. Laminitis (founder) is inflammation of the tissue that attaches the foot’s coffin bone to the hoof wall. Laminitis is extremely painful and causes instability.

In advanced laminitis cases, the coffin bone detaches and rotates within the hoof wall; this condition is often fatal.

Infection

Bacterial infections often result when dirt enters the site of a compound fracture. Compound fractures occur when the broken leg bone protrudes from the skin.

Horses with compound fractures are typically euthanized. Infections can also occur when broken bones are repaired during surgery, even without a compound fracture.

Do you have to kill a horse if it breaks its leg?

Not every horse has to be killed when it breaks its leg, but most do. The reason horses are euthanized when they break a bone in their limb is because they have minimal chance of recovery and suffer extreme pain.

Horses with a broken leg have a poor chance of healing because of the equine leg’s anatomical structure, plus is almost impossible to immobilize a horse long enough for its leg to heal.

Broken legs cause suffering.

A horse that breaks a leg is in extreme pain when the injury occurs and during recovery. Drugs can give some relief, but too much pain-relieving medication and the horse is likely to re-injure itself.

The administration of pain-relieving drugs must be done carefully, so the horse isn’t overmedicated. Horses’ pain tolerance is an essential factor when deciding if surgery is an option.

Common breaks in horses legs.

The bones most commonly fractured are in the lower limbs of horses. Horses’ lower legs are thin relative to the amount of weight they carry. When a horse takes a bad step or tumbles, the bone is placed under immense pressure and sometimes snaps.

The pedal bone. 

A horse typically breaks its pedal bone by kicking a wall or landing badly on an uneven surface. Pedal bone fractures can heal, and most do well with rest and the application of a unique shoe.

If the pedal bone break also involves the coffin joint, a surgical screw may be needed to help heal the injury.

Pastern bone

The pastern bone is directly above the horses’ hoof and below the fetlock. It incorporates two bones, the long and short pasterns, and are held together by ligaments.

A horse can heal from a simple non-displaced fracture of the pastern with proper care. Pastern breaks are often treated with wraps and stall rest. However, surgical screws are also commonly used.

Most horses make a full recovery from simple pastern breaks, but the prognosis is not as good when the fracture is more complicated. Horses typically survive but don’t return to competitive events.

Sesamoid bone

Sesamoid fractures are common in horses. The sesamoid bones are small bones at the rear of the fetlock joint. The location of the break is pivotal in determining the chances of recovery.

If the break occurs at the top, surgery is an option; however, if the bone is broken in the middle or into small pieces, the horse is unlikely to recover.

Cannon bones

The cannon bone is between the fetlock joint and the animals’ knee. When a horse breaks the long cannon bone, the fracture usually runs down into the fetlock.

A horse can recover from these longitudinal breaks with rest, screws, and leg wraps. But if the bone is broken horizontally, the prognosis is not hopeful, and horses often have to be put down.

Carpal bone

The carpal bone is the knee and often breaks off a small chip in competitive horses. These chips can be felt when you run your hand on the animals’ joint; they may happen on the bones’ front or sides.

If the chips are minuscule, they don’t usually limit the animals’ performance but may cause swelling and joint pain. Larger chips can be surgically removed, and the horse given time off to recover.

There are also slab bone fractures of the knee, which is more extensive and requires surgical screws.

Conclusion

Horses can’t live with three legs primarily because too much pressure is placed on the remaining limbs, and they can’t raise themselves from the ground. Prosthetics are an option for certain equines that lose a leg, but it’s rare to find the perfect canidate.

Horses are euthanized when they break a leg because of the risk of infection, pain tolerance of the animal, and the slim chance of a successful recovery. However, some horses do come back leg fractures.

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