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Medical Index
First Posted
Aug 3, 2010

Equine (Horse) Seizures

by Debora Johnson

Seizures in horses can be caused by a myriad of reasons; however, true seizures deal with electrical activity within the cerebral cortex of the brain. It is often difficult to determine what is causing the seizure. Below are a few possible causes.

Some Causes

  • Heat Stroke
  • Dehydration
  • Epilepsy
  • Hypoglycemia (low blood glucose)
  • Metabolic imbalances
  • Brain tumors
  • Infections in the brain (meningitis), bacteria, viruses (herpes), fungi (rare) or protozoal myelitis
  • Abscesses in the brain as a result of strangles (Streptococcus)
  • Kidney problems (Lack of electrolyte retention for the brain)
  • Toxins
  • Drug reactions
  • Head trauma
  • Moldy forage such as corn
  • Improperly given injections (particularly procaine penicillin)

Tools for Diagnosing Cause of Seizures

  • Spinal fluid tap
  • Bloodwork
  • Radiographs
  • Electrical encephalogram (EEG)
  • Visual and history


It is difficult to give a prognosis for seizures because it depends on what is causing the seizures. For example, antibiotics can cure seizures caused by bacterial infections while herpes virus seizures can not be cured at the present time--only managed.

I am sad to say that we had to put down one of my husband's horses because, among other problems, he had seizures. Tucker was a large horse and his violent seizures put everyone at risk--people and other horses, as well. Working with our vet we tried to determine what was causing his seizures but were unsuccessful. (We believed he had a cancerous brain tumor) After many emotional months and "mucho dinero" spent, we determined that we had no choice but to euthanize him. That was a really sad day. I hope that you never have to go through that kind of experience.

Tucker, Kentucky Mountain Horse by Goldfinger

Medical Index