[Statistical study of the digestibility of dietary manganese in cattle. Specifications on their requirements for this...

The authors have studied the fate of ingested manganese by the balance method in metabolism stalls with; --198 adult non-pregnant dry cows and 118 adults non-pregnant lactating cows of the Friesian breed which were fed respectively 58 and 41 different winter rations; --2 groups of 6 cows of the same breed which received only fresh cut grass ad lib; --4 groups of 12 steers of the Belgian Blue White breed which used on trials for intensive meat production. The correlation between Mn intake, digestible and faecal Mn and the other nutritive factors of the above-mentioned rations have been calculated. Two factors only, manganese intake and potassium intake, could influence the metabolism of manganese. Our results demonstrate also that if it is possible now to evaluate the manganese requirements according to the potassium intake, the minimal manganese requirements in case of potassium intake meeting no more than the real potassium requirements according to A.R.C. (1965) are quite variable from one group of animals to another, being 5 mg/kg in the adult cow and 50 mg/kg in the young growing cattle. Owing to these differences and to the possible adverse effect of potassium intake, the authors think that circumstances leading to a manganese deficiency could eventually be met.