Growth responses to selenium in lambs

Abstract

Extract

Until recently, selenium as a dietary constituent was regarded as of importance only where it occurs in excess of certain well defined limits. When these limits are exceeded, selenium toxicity develops, either in the acute form; in the subacute form, called “blind staggers”, following the ingestion of seleniferous weeds; or in the chronic form, called “alkali disease”, caused by the prolonged grazing of pasture or forage crops containing smaller amounts of selenium. In selenium poisoning areas, about 5 p.p.m. in herbage is considered to be the tolerance limit for ,livestock. Smaller amounts have been estimated to be dangerous in man (Garner, 1957).