Calcium digestibility in cows as influenced by the excess of alkaline ions over stable acid ions in their diets.

1. Statistical analyses were carried out on results obtained under strictly-controlled conditions in metabolism stalls with forty-one different rations fed to 127 adult non-pregnant dry cows, and with fourteen other different rations fed to thirty-five adult non-pregnant lactating cows that had calved 2-6 months earlier and whose daily milk production ranged from 11 to 20 kg. 2. Correlations between calcium digestibility and values for the sum of the alkaline ions sodium and potassium minus the sum of the stable acid ions chloride, sulphate and phosphate were calculated for all fifty-five experimental diets. 3. The results showed that the excess of the anions over the cations, in rations maintaining a positive Ca balance but not in rations allowing a negative Ca balance, increases the absorption of Ca from the intestine. Phosphorus, not alone but with chloride and sulphate, is the most important component of this effect.

Immunoglobulin transfer to calves and health problems in large bovine units.

The serum immunoglobulin levels were studied in 215 calves born on 4 farms. Each farm had at least 60 cows. There was a great variation in the immunoglobulin levels at 48 hours. In those cases where the quantity and Ig concentration of colostrum was measured it was found that the serum Ig level was correlated with the total amount of Ig ingested. Where only the serum level was measured it was found that suckled calves had higher levels than bucket-fed calves. Immunoglobulin levels were not correlated with the incidence of diarrhoea or pneumonia nor with the viability of calves although calves with less than 8 mg/ml IgG1 showed a slightly higher incidence of diarrhoea. The globulin concentrations in colostrum were not influenced by the breed, the season, the number of calvings, the length of the dry period and the level of feeding during this period but the time of the first feeding or milking proved to be of prime importance.

[Statistical study of the digestibility of dietary manganese in cattle. Specifications on their requirements for this element]. / Recherches statistiques sur la digestibilité du manganèse alimentaire chez les bovins. Précisions sur leurs besoins en cet élément

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.