If you cannot see images at all on my site click here for an explanation
Medical Index
First Posted: Sept 1, 2010
Sep 1, 2010

Shivers, Shivering and Stiff Horse Syndrome in Horses

by Debora Johnson

What is shivers? Does shivers have a genetic component? Is it more common in some breeds than others? Is is gender sensitive? What causes shivers? What is affected by shivers? Can shivers be treated? Can shivers be cured?

What is Shivers?

Shivers has been around for centuries. It is seen in both male and female equine. Shivers or shivering is a chronic nervous or neuromuscular syndrome in horses. It is present in all age groups from foal to geriatric. Sometimes shivers is referred to as "stiff horse syndrome."

Does Shivers Affect All Breeds?

The larger breeds of horse such as Belgian draft horses and other draft horses, warmblood, warmblood crosses and the lighter breed of horse including light harness horses, standardbreds, hunters, hunter-jumpers, hacks, quarter horses, and thoroughbreds have presented with shivers. The pony breeds generally do not develop shivers. There is some suspecion that there is a genetic component to shivers--that horses may be predisposed to it. This, however, has not been scientifically proven, as yet.

What Are the Symptoms of Shivers?

Initially you may not even notice that your horse has signs of shivers. It may be quite difficult to detect. As the disease progresses, you might detect trembling, the horse's tail may be held erect and tremble, involuntary muscle spasms, jerky movements in the pelvic area and hind limbs, the hind limbs are flexed behind the horse and the horse is unable to put the leg down, the horse is unable to back up properly. The forelimbs can also be affected. The neck, trunk, ears, eyelids, lips and cheeks can have spasms, as well. You may notice an involuntary twitching or rapid blinking. The horse's lips might quiver involuntarily. You may see atrophy in the thigh and hind end muscle weakness. There may be overall muscle atrophy. Some horses with Shivers tend to sweat more than normal. They also do not like to lie down. They stand stiffly with their hocks help wider apart than normal.


Unfortunately, there is no treatment for shivers. Rest will sometimes help but not cure. With work shivers usually returns. Diet has been used in the treatment of shivers. High-fat, low-carb diets have been tried. Sometimes it has helped in the early stages of the disease. Research into shivers has not shown that there are any specific lesions in the central nervous system. The cause of shivers is virtually unknown. It is throught to be neurologic.


Shivers is presently, a progressive and debilitating disease. To date, there is not any happy ending.

Diseases That Mimic Shivers

There are several other diseases and conditions that will mimic shivers: Among them are peripheral neuropathy (nerve generation), equine protozoal myelitis (EPM), stifle problems (upward fixation of the patella), stringhalt and fibrotic myopathy. (In fibrotic myopathy, the affected limb is pulled back and down before the end of the protraction phase, resulting in a lengthened weightbearing phase and a shortened cranial phase. The signs are most obvious at the walk.)(In stringhalt, the affected limb is hyperflexed during the cranial or swing phase, while the stepwise caudal jerking movement before foot contact does not occur.) Equine Motor Neuron Disease (EMND) is another disease that may mimic shivers. It is caused by a vitamin E deficiency. The horse will have progressive symptoms such as weight loss, muscle wasting, tremors, excessive sweating, and a tucked-up abdomen. A low head carriage, abnormal gait, and abnormal tail elevation Shivers has also been reported after a horse has had trauma such as a severe fall. Osteoarthritisas has also been associated with some cases of shivers.

For More Information:

Shivers in the Horse: A Review
Equine Shivers

Medical Index