By: Dr. Lydia Gray, SmartPak Medical Director/Staff Veterinarian
Shivers is a neuromuscular condition of the hindquarters that may be difficult to diagnose in the early stages but becomes more obvious as classical signs appear. When a horse with Shivers is backed, asked to pick up a hind leg, or even just experiences stress or excitement, it may hold up one hind limb which shakes or trembles, as well as raise its tail which will also shake or tremble. Typically found in draft horses, warmbloods and their crosses, it is occasionally seen in quarter horses, thoroughbreds and standardbreds but rare in ponies. Of unknown cause, Shivers has been reported in horses as young as one to two years old.
There is no treatment for Shivers. Because breeds of horses affected by Shivers coincidentally also have high rates of Polysaccharide Storage Myopathy (PSSM), some veterinarians and owners are feeding a low-carb/high-fat diet in an attempt to reduce signs. Maintaining adequate levels of Vitamin E and Selenium is important, as is providing as much turnout as possible. Sometimes rest reduces the signs but they often return when exercise is resumed.
In the early stages, Shivers can be mistaken for other disorders affecting the hindquarters such as Stringhalt, Upward fixation of the patella, Fibrotic Myopathy, "Stiff horse" Syndrome, Equine Motor Neuron Disease, EPM and others. Any horse with a gait abnormality or muscle dysfunction should be examined by a veterinarian to determine the cause and begin appropriate treatment, when possible. Unfortunately, Shivers carries a poor prognosis because it is progressive and debilitating.
SmartPak strongly encourages you to consult your veterinarian regarding specific questions about your horse's health. This information is not intended to diagnose or treat any disease, and is purely educational.