The effect of body stores and of method of supplementation on the efficiency of calcium and phosphorus utilization by sheep

Abstract

(1) The Ca and P metabolism of two groups of young sheep, depleted of these minerals, was investigated in a series of three balance studies. (2) During the first 10 days on the bone meal supplemented ration, the inorganic P of the blood rose sharply from approximately 2•0 to 5•0 mgm. per 100 c.c. of blood, a level which was more or less maintained to the end of the experiment. (3) Under the conditions obtaining the method of bone meal supplementation had no influence on the efficiency of utilization of Ca and P. The implication of this for the problem of phosphate feeding under practical conditions is briefly discussed. (4) Ca and P utilization dropped considerably in the course of the 80 days on the enriched ration. Retention figures for Ca decreased from 22•5 to 12•7 per cent. and those for P from 53•1 to 32•2 per cent. (5) Due to the fact that no observations are available on the extent of replenishment during the period of bone meal feeding the final interpretations of these results must await the outcome of further investigations.