The aetiology of phalaris straggers in sheep. IV. The site of preventive action and its specificity to cobalt

Abstract

The preventive activity of cobalt against phalaris staggers in the sheep is very probably restricted to the rumen. In this disease cobalt does not act within the tissue cells nor within the intestines; cobalt injected intravenously is without effect. The destruction of the toxic substance present in the phalaris does not depend on the production of vitamin B₁₂ by the rumen flora. The probability that cobalt acts by ensuring the proliferation of microorganisms in the rumen which accomplish this detoxication is discussed. The preventive action is specific to cobalt administered orally; frequent doses of a supplement that provide the daily equivalent of 10 mg each of boron, copper, iron, magnesium, manganese, molybdenum, nickel, titanium, and zinc fail to prevent the malady.