[Supply of magnesium in cattle].

The supply of magnesium is determined by the concentration of Mg in the ration, the absorption coefficient of Mg in the fodder and by the feed intake. In lactating cows, the supply of Mg usually will be sufficient when concentrates contain 5 g. or 7 g. of Mg per kilogram during the housing and grazing period respectively. For dry cows fed roughage only a daily supplement of 50 g. of MgO per cow may be required.