Shivers in Horses

What Is Shivers in Horses?

Shivers is a chronic and progressive neurologic disease characterized by an abnormal, trembling gait when the horse backs up.

Essentially, the horse’s legs looks like they’re “shivering.” Shivers has been around for years, reported in a variety of breeds, and considered relatively rare.

Shivers appears to be breed-related, so it’s possible that there is a genetic basis or predisposition for the condition.

The most recent research found that one cause of shivers is related to injury or damage to Purkinje cells (specific neurons) in the cerebellar cortex of the brain.

Shivers can sometimes be confused with stringhalt in horses. While both conditions do have a neurological component, stringhalt is characterized by an involuntary, exaggerated upward movement of one or both hindlimbs. It’s usually seen with every stride at a walk. Shivers is seen during backing and only seen when moving forward at a walk in severe cases.  

Symptoms of Shivers in Horses

Clinical signs of shivers usually begin by 5 years of age and typically progress in severity as a horse becomes older.  

Common clinical signs seen with shivers include: 

• Hyperflexion or hyperextension of the hindlimbs when backing

• Muscle trembling

• Muscles in the face and neck may contract in some cases

• Resistant to hindlimbs being picked up, such as to clean hooves or have shoes applied by a farrier

• Muscle atrophy

Causes of Shivers in Horses

The cause of shivers in horses is still being researched today, as much is unknown. It seems to be caused by damage to the Purkinje cells (specialized nerve cells) in the cerebellum part of the brain. 

While males and females can both be affected, geldings are more likely to be diagnosed with shivers. Also, horses that are tall (above 16.3 hands) are more likely to be affected than shorter horses. Shivers has been diagnosed in several breeds including draft horses, warmbloods, Quarter horses, and Thoroughbreds.    

Excitement and stress can also lead to an episode of shivers.

How Veterinarians Diagnose Shivers in Horses

The diagnosis of shivers is based on a physical exam, the characteristic gait when the horse moves backward, and ruling out other diseases like stringhalt, EPM, and lameness.  At the time of this publication, there are no diagnostic tests for shivers in horses.

How To Treat Shivers in Horses

Currently, there is no treatment for shivers, but proper management can help to reduce the clinical signs. 

Management of Shivers in a Horse

Once a horse has been diagnosed with shivers, routine management is the best way to help them have fewer incidents. Some management practices that have been shown to help horses with shivers include: 

• Consistent exercise

• Access to turnout

• Limiting time in a stall

• Limiting each horse’s individual triggers 

• Reducing stress and excitement 

Work with your veterinarian to develop the best protocol for your individual horse. 

Massage, acupuncture, and veterinary spinal manipulation therapy may be helpful in keeping a horse comfortable and competitive.

If a horse has severe shivers and develops muscle atrophy, they could be more prone to injuries and lameness. 

Supplements to Help Shivers in Horses

Current research suggests that the antioxidant vitamin E may be beneficial in horses at risk for shivers. It plays a role in development of healthy nerve and muscle tissue. 

Vitamin E is an antioxidant (important for healthy nerve and muscle tissue) and may be critical for horses at risk for shivers. Supplements including vitamin E that may be helpful for your horse include Nano E® or Elevate®.