Syndrome of Cerebrocortical Necrosis Experimentally Induced in Calves by Administration of Amprolium

Abstract

Bouda J., P. Jagoi, V. DvoUk, L. Pivnik: Syndrome of Cerebrocortical Necrosis Experimentally Induced in Calves by Administration of Amprolium. Acta vet. Bmo, SO,1981: 109-116 In the experiment into which three experimental and four control calves were included the syndrome of cerebrocortical necrosis (CCN) was induced by the administration of Amprolium. Pathogenesis and symptomlltology of the condition were followed. After the intraruminal administration of Amprolium (O.5g/calf/day) the clinical signs appeared in two calves after six weeks while in the third calf after 56 days. The main clinical features were: inappetence, blindness, increased excitability, symptoms of static and kinetic ataxia. Calves rose with difficulties, had difficulty avoiding objects, muscular tremor and opisthotonus appeared, when falling tonic--clonic convulsions and paddling movements were observed. The observed clinical signs were identical with those of spontaneous cases of CCN in calves.Statistically significant decrease of thiamine content was determined in cerebral cortex, cardiac and skeletal muscle of experimental calves. In liver tissue there was no significant decrease of thiamine level. Fourteen days after the administration of Amprolium the erythrocyte transketolase activity was found to decrease while the thiamine pyrophosphate effect in blood increased. Pathologico-anatomical examination of brain revealed cerebral oedema and yellow coloured foci on some gyri. Histopathological changes in these parts were characterized by necrosis of the grey matter and enormous infiltration of macrophages. However, when compiuing the plasma levels of vitamin A, E and C, minerals, Na, K, Ca, Mg, inorganic P, Zn, Cu, or urea, glucose, asparateaminotransferase and gamma glutamyl transferase activity, acid-base balance in the blood and of some parameters in the rumen fluid, no significant differences were found between experimental and control groups.