Stringhalt is a condition that affects a horse's hind legs, causing them to jerk upwards in an exaggerated fashion when walking or trotting. While alarming to see, stringhalt itself is not usually a serious problem. However, it can indicate an underlying neurological issue that should be addressed.
What Causes Stringhalt?
Stringhalt is caused by damage to the lateral digital extensor tendon that runs down the back of the hind legs. This tendon controls the extension of the leg. When the tendon is damaged, it becomes hypersensitive and overreacts to normal nerve signals from the horse's brain telling the leg to move. This causes the exaggerated leg jerk upward. There are several potential causes of stringhalt:
Injury to the tendon from trauma or excessive strain
Nutritional deficiencies, such as Vitamin E, that weaken tendons
Toxins from plants like hoary alyssum that damage nerves
Viral infections like equine herpesvirus that can cause neurological damage
Degenerative diseases of the spinal cord in older horses
The classic symptom of stringhalt is the exaggerated leg jerk upward when the hind leg flexes. Usually both hind legs are affected. The jerky movement is most noticeable at the walk and trot when the leg is flexing. It is usually less apparent when the horse is standing still.
Depending on the underlying cause, horses may have other neurological symptoms like muscle atrophy, weakness, or dragging toes that accompany stringhalt.
If the stringhalt is mild, treatment may not be necessary. More severe cases require treating the underlying cause:
Nutritional imbalances are corrected through dietary changes and supplements
Damaged tendons can benefit from anti-inflammatory medications, rest, and therapeutic ultrasound
Viral infections are treated with anti-viral medications
Injuries, trauma, and degenerative diseases may require surgery and rehabilitation exercises
The prognosis depends on the severity and original cause of the stringhalt. Nutritional and toxin-induced stringhalt often resolve with correct diet and removing exposure. Cases caused by neurological damage have a poorer prognosis. With proper treatment and management though, most horses can continue to lead comfortable lives despite having stringhalt.