CCN (Cerebrocortical Necrosis) or Polioencephalomalacia (Polio), is a noninfectious neurological disease of cattle with two basic forms:

  • Acute form: Sporadically seen in feedlot cattle, where affected animals are often found in a coma.
  • Mild or sub-acute form: Sporadically seen in animals on pasture.


  • Pathologically, CCN is characterized by brain swelling and necrosis of the cerebral cortex.
  • Results from interference with brain metabolism, associated with a deficiency of thiamine (Vitamin B1) at the cellular level.
  • Thiamine deficiency can occur due to its destruction or inadequate production in the rumen.

Clinical Signs:

  • Dullness, head pressing, blindness, opisthotonos (head pushed back and up), nystagmus (involuntary eye movement), and paddling movements of the limbs.
  • Affected calves show signs of meningitis due to brain cell destruction by the lack of B1.
  • Calves may be found away from the group with a staggering gait, will go off their food, and if untreated, will have convulsions and die.


  • Isolate the animal in a quiet, well-bedded pen with feed and water readily available.
  • Administer vitamin B1 intravenously, followed by muscle injections every three hours for one to two days.
  • If the animal is found late, other treatments like a drip may be required.

Prevention Tips:

  • Maintain good rumen health
  • Supply calves with vitamin B1-fortified lick buckets during summer months
  • Feed extra vitamin B1 orally
  • Provide fibre in troughs in fields
  • Closely monitor calves and act quickly when symptoms are seen.
  • Avoid or slowly introduce feeds and water with a high sulfur content.
  • Be cautious when animals start grazing after a long period without grass.

If one animal is affected, it may be necessary to give the entire group a B1 injection to prevent further cases.

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