Stringhardt the Horse | PetMD

What is a horse stringhalt?

Equine stringhalt, also known as springhalt, is a condition that refers to abnormal movement of a horse’s hind legs.

Stringhalt is a condition in which one or both of a horse’s hind legs suddenly and violently bend towards the abdomen and then bounce back to the ground in one go. Stringhalt is relatively common in horses, but exact statistics on its occurrence are unknown, as most cases are not reported by horse owners or veterinarians. Stringhalt can occur in any horse, regardless of breed or age.

There are two types of string injuries in horses: classic string injuries and bilateral string injuries.

• Double-sided string halt—Also known as Australian Stringhalt. It affects both hindquarters and usually occurs simultaneously, so several horses are affected at the same time. Although it is called Australian Stringhalt, it has been reported all over the world.

• Classical Strings—Usually affects only one hind leg and occurs in isolated cases. This type of stringhalt has been reported worldwide.

Symptoms of Stringhalt in Horses

• Mild to slightly jerky gait

• Extreme hyperflexion of the hind legs

• Hindlimb muscle atrophy

• Stringhalts on both sides can have a “bunny hopping” gait

• Occurs while moving forward, backward, or turning

• Most or all of the horse’s stride is affected

• Aggravated by excitement, cold weather, or strenuous exercise

If your horse exhibits any of the above symptoms, contact your veterinarian.

Causes of Stringhalt in Horses

Causes of bilateral string halts

Bilateral stringhalt in horses is caused by the ingestion of poisonous plants. Plants commonly associated with bilateral stringhalt include:

• Oyster mushroom

• Fireweed

• Mustard Weed

• Dandelion

Ingestion of these types of plants occurs most frequently in late summer. Horses may graze on dry grasses. Unidentified toxins contained in these weeds affect the long nerves in the horse’s body. The toxins damage the outer layer of nerve cells, preventing the nerves from properly transmitting information from the brain to the muscles.

Scientists have attempted to determine the exact toxin and amount needed to cause Stringart’s disease, but have not been able to pinpoint it at this time. Complicating the matter is that individual horses may have different levels of sensitivity to the toxin, and plants vary in toxin concentration.

Classic stringhalt causes

At present, the exact cause of classic stringhalt in horses is unknown. Classic stringhalt can occur following a hind limb injury or as a secondary consequence of equine protozoal myeloencephalitis (EPM) or equine motor neuron disease (EMND).

Additionally, foot diseases such as hoof abscesses and hock arthritis have also been associated with the occurrence of stringhalt in horses. Depending on the underlying cause of the disease, clinical signs may be the result of mechanical influences such as adhesions, disturbances of limb reflexes, or pain responses.

How Veterinarians Diagnose Stringhalt in Horses

Veterinarians diagnose stringhalts solely on a physical exam and medical history, and once other conditions such as arthritis and abscesses have been ruled out, a stringhalts diagnosis is based on the characteristic jerky gait seen during a physical exam.

Electromyography (EMG), a diagnostic procedure that can measure muscle responses to nerve stimulation, can support the diagnosis of Stringhart and help document abnormal nerve function, but is not required to make the diagnosis.

Horses with both classical and bilateral stringhalt will not show any abnormalities in routine blood tests. Because scientists have not yet identified the exact toxins contained in bilateral stringhalt, specific blood tests for the toxins are not available.

Treatment of Stringhart in Horses

Treatment of bilateral stringhalt in horses

Bilateral stringhart’s disease is treated by keeping the horse away from poisonous plants, and during the recovery period, ensuring the horse has access to clean, fresh water, good quality hay or uncontaminated pasture, and good husbandry and hoof care.

Classic Stringhalt Treatment for Horses

Other causes of pain (arthritis, chronic pain, Before embarking on any treatment for Stringhardt, check your horse for any hoof diseases, such as shoeing/trimming or hoof abscesses.

Classic Stringhalt treatment:

In classic stringhalts, surgical correction can sometimes be successful. The procedure involves removing part of the tendon that passes over the hock and part of the muscle it inserts into. The results of surgical treatment can vary from no improvement in the horse’s condition to almost complete resolution of the clinical signs. Unfortunately, there is no way to predict how an individual horse will respond to surgery.

Recovery and Management of Stringhart in Horses

Almost all cases of bilateral Stringhardt’s disease eventually make a full recovery once the horse is removed from the toxic pasture. However, recovery is slow and can take up to 18 months depending on severity. Return to full athletic ability is unpredictable and will vary from horse to horse. Your equine veterinarian can help determine recovery steps appropriate for your horse.

Recovery from classic string heart disease depends on the severity of the condition and the underlying cause. Despite treatment, most cases will gradually worsen before stabilizing. This is because the inflammation and damage that initially occurred has subsided and there are now residual effects.

Classic stringhalt in horses may improve over time, but recovery may take months or even years. If the condition does not improve, horse owners will need to manage the condition long-term. Long-term management will vary depending on the severity of the condition.

Mild cases may be manageable by simply paying attention to your horse’s condition and monitoring it for changes. Severe cases may require you to retire your horse. Your horse’s environment should be watched for tripping hazards and anything that could prevent the horse from getting its own food and water. Your vet can help you establish a management routine.