Equine neuroaxonal dystrophy

Veterinary advice should be sought before applying any treatment or vaccine.

Equine Neuroaxonal Dystrophy

Equine neuroaxonal dystrophy (NAD) is a degenerative central nervous system disease of horses. The disease is similar to equine degenerative myeloencephalopathy (EDM). NAD is thought to be inherited in Morgans, Appaloosas, and Quarter Horse breeds, which are the breeds most frequently affected. Clinical signs of NAD usually start to become apparent when horses are younger than 2 years of age.

Clinical Signs of NAD in Horses

Horses with NAD may initially appear depressed or dull, with weakness and mild to severe ataxia which appears as a gait abnormality. The gait abnormality affects all four limbs of the horse; however, the hind limbs are most often the most severely affected. Horses with NAD may stand with a wide-base stance at rest.

Differences between NAD and EDM

NAD and EDM are both diseases that cause.
degenerative changes in the central nervous system. The differences between them depend on the specific areas affected within the horse's central nervous system.

How NAD is Diagnosed

Diagnostic tests that are useful for determining whether a horse has NAD include a neurologic examination, radiographs (of the vertebrae of the neck), spinal tap, and measurement of vitamin E in the blood and diet. Your veterinarian will need to rule out other diseases which cause gait abnormalities, such as EDM, trauma, wobblers, and equine protozoal myeloencephalitis (EPM). A Postmortem exam is currently the only method to definitely diagnosis NAD or EDM.


Gait abnormalities
Ataxia (in all four limbs)
Base-wide stance at rest
Altered level of consciousness
Decreased to absent menace response
Proprioceptive positioning deficits


  • History
  • Clinical signs
  • Neurologic exam
  • Radiographs
  • Measurement of vitamin E in blood
  • Postmortem exam



Vitamin E therapy: Supplementation of Vitamin E in their diet
  • Supplementation of pregnant broodmares and foals with α tocopherol during the first two years of life
  • Ensure diet has sufficient vitamin E

Scientific Research

General Overviews

Age Range

Most commonly affects young horses 1 to 2 years of age

Risk Factors

  • Horses of the Morgan, Quarter Horse, or Appaloosa breeds