EFFECTS OF REDUCING DIETARY CALCIUM AND OR PHOSPHORUS ON PERFORMANCE AND BODY-COMPOSITION IN MALE KIDS/

In a two-factorial experiment, five kids per treatment (initial weight 12.5 kg) were fed, for 63 days, concentrate mixtures containing, per kg dry matter, 10.9 or 3.9 g Ca and 4.6 or 2.0 g P, respectively, and straw at constant ratios of 5:1. Intake and weight gain were significa ntly reduced by low dietary P, but not by low dietary Ca. The digestib ility of organic matter was reduced by low P and the digestibility of total lipids was increased by low Ca. Although excretions of both elem ents took place mainly in faeces, the dietary effects on quantities ex creted in the urine were also significant. Plasma inorganic phosphate concentrations were significantly increased by a low Ca intake and dec reased by a low P intake. The plasma Ca concentration was increased by a low dietary P concentration No significant effect on the activity o f alkaline phosphatase could be determined. The accretion of Ca, P, an d Mg in empty bodies was reduced by a low Ca intake, but this ceased t o occur on diets low in Ca and P, and it was even negative on diets ad equate in Ca and low in P. Comparable differences were found for isola ted femora.