EN
Stationary cerebrocortical necrosis was observed in a sheep flock. During the consecutive three years 10% of lambs, 3—4 months old were affected. It was found that the appearance of clinical signs preceeded an increase of plasma pyruvic acid level. Therefore, the increase of the content of pyruvic acid may be helpful for the detection of subclinical forms of the disease in a flock but not in an individual sheep.