Shivers

Below is a video taken of a warmblood gelding who has been diagnosed by vets to be suffering from Shivers.

Shivers, though uncommon in horses, were traditionally associated with heavy breeds. However, it has also been observed in other breeds like warmbloods, standardbreds, and thoroughbreds.

Detecting early signs of Shivers can be challenging. In the aforementioned video, the horse’s struggle to raise its hind legs during farrier work raised concerns. Typically, Shivers is characterised by tremors and exaggerated flexion of the rear limbs, particularly noticeable when backing up or lifting the hind legs. The video also shows the horse raising its tail during an episode. It is worth noting that Shivers is not commonly found in pony breeds.

The exact cause of Shivers remains uncertain, with different research perspectives. Some suggest an abnormal response in the nerves responsible for sensing muscle and joint position and tension. Another hypothesis suggests a genetic component.

Misdiagnosis of Shivers as conditions like EPM and PSSM can occur. Horses with EPM and PSSM tend to respond well to high-fat, low-carbohydrate diets. Unfortunately, there is currently no known cure for Shivers. This progressive and debilitating condition offers no favourable outcome at present.

Signs and Symptoms

Shivers is a neuromuscular disorder that primarily affects horses. It is characterised by involuntary and repetitive muscle contractions, most commonly seen in the hind limbs. The exact cause of Shivers is still not fully understood, but it is believed to have a neurological origin.

Signs and symptoms of Shivers can vary in severity and may include:

  1. Difficulty lifting the hind legs: Horses with Shivers often have difficulty picking up their hind legs for tasks such as shoeing, hoof trimming, or backing up. They may exhibit trembling or jerking movements while attempting to lift the leg.
  2. Tail elevation: During episodes of Shivers, some horses may raise their tail, possibly as a compensatory response or due to associated muscle tension.
  3. Hyperflexion of limbs: Affected horses may display exaggerated flexion or trembling of the hind limbs, especially when the leg is held in a flexed position or while backing up.
  4. Muscle tremors: Tremors or spasms in the hindquarters or overall muscle twitching may be observed during episodes or even at rest.
  5. Balance and coordination issues: Horses with Shivers might have difficulty maintaining balance or coordination, particularly during activities that require precise movements or changes in direction.

It is important to note that Shivers can vary in its presentation and severity among individual horses. Some cases may progress slowly over time, while others may exhibit more rapid deterioration.

Diagnosing Shivers involves a thorough veterinary examination, including a physical evaluation and observation of the horse’s movements. Additionally, diagnostic tests such as nerve blocks, electromyography (EMG), and muscle biopsies may be performed to rule out other potential causes and confirm the presence of Shivers.

Management

While there is no specific treatment for Shivers, management strategies can help improve the affected horse’s quality of life. These may include:

  1. Exercise and turnout: Regular exercise and turnout in a safe environment can help maintain muscle tone and overall well-being.

  2. Dietary adjustments: Providing a balanced diet that meets the horse’s nutritional needs, along with proper weight management, can support their overall health.

  3. Stress reduction: Minimising stress factors in the horse’s environment, such as stable management practices and social interactions, can be beneficial.

  4. Symptomatic support: Recommended medications or supplements to help manage muscle tremors and reduce discomfort, although their effectiveness in treating Shivers is still not well established.

It is crucial to consult with a experienced equine veterinarian for accurate diagnosis, ongoing monitoring, and guidance on the best management approach for horses affected by Shivers.