What are the Causes of Tremors in Horses?

Muscle tremors in horses are almost always a cause for concern. Healthy horses do not normally experience tremors and, in most cases, the tremors often are a symptom of a more severe underlying health problem. Several different conditions affecting horses can manifest in the form of muscle tremors. If your horse is experiencing tremors, you should contact your veterinarian immediately for a proper diagnosis of the problem and to obtain treatment for the condition.

  1. Hyperkalemic Periodic Paralysis

    • Hyperkalemic periodic paralysis (HYPP) is an inherited illness that manifests predominantly in Quarter Horses. It also affects breeds that have close ties to the Quarter Horse, such as Paints. Horses with HYPP inherit the condition when both parents are carriers of the problem gene. Such horses may experience muscle tremors, weakness, collapse, muscle paralysis and sudden death. Horses that test positive as HYPP carriers should not be used for breeding.

    Shivers

    • Shivers is another inherited condition that causes muscle tremors in horses. Shivers primarily affects draft, warmblood and warmblood crossbreeds. Affected horses may experience muscle tremors and tail tremors, as well as unusual flexion in the rear limbs. The severity of shivers varies depending on the affected horse. Some horses have mild or no symptoms, while others ultimately may suffer from extreme weakness and atrophied muscles, and eventually may be unable to get up off the ground or walk.

    Poisons and Toxins

    • Consuming certain poisonous or toxic substances also can cause a horse to experience muscle tremors. Consuming toxic vegetation can cause muscle tremors, as well as a vast assortment of other health problems and conditions, including drooling, loss of coordination, diarrhea, rapid breathing, rapid pulse and even death. If your horse experiences a sudden onset of multiple symptoms or you believe your horse has consumed a toxic plant or substance, you should call your veterinarian immediately for treatment options.

    Other Potential Causes of Muscle Tremors

    • Though muscle tremors are not one of the most common symptoms experienced by a colicking horse, some horses may experience tremors if colicking severely. The tremors will be accompanied by an assortment of other symptoms, including rolling, laying down, kicking at the girth and barrel area, straining, a lack of bowel movements and extreme discomfort. Other problems that can cause tremors include nutritional deficiencies in the horse's diet, dehydration and heat-related health problems, such as overheating and heat stroke.