The Aetiology of Cerebrocortical Necrosis: The Effects of Administering Antimetabolites of Thiamine to Preruminant Calves

SUMMARY Milk-fed preruminant calves were given repeated doses of one of three thiamine antimetabolites; only those receiving Amprolium * developed cerebrocortical necrosis. Those receiving oxythiamine by intramuscular injection died in from 7 to 19 days. One calf given pyrithiamine by the same route died after 21 days on experiment. The other was killed in apparent health after 47 days. Peripheral perineuritis was demonstrated histologically in the first calf; slight similar lesions were seen in the second. Four calves given Amprolium orally died with cerebrocortical necrosis in from 30 to 41 days. Intraperitoneal injection of two calves with Amprolium was followed by the death of one of them after 41 days; cerebrocortical necrosis was again evident. Control calves, injected with thiamine at the same time as the doses of antimetabolite, remained apparently healthy.