The Calcium and Phosphorus Requirement of White Leghorn Pullets from 8–21 Weeks

Abstract

THE National Research Council (1960) has set the calcium and phosphorus requirements of growing chickens from 8 to 18 weeks of age at 1.0 and 0.6%, respectively. It is further indicated that a portion of the phosphorus must be supplied in inorganic form. Evidence to support such high requirements for these two elements during the developing period (8 weeks to 18 to 21 weeks of age) is meager. Numerous investigations have indicated that the above indicated values are necessary for early chick growth and normal bone ash. However, few studies have been conducted to determine requirements during the growing or developing period. Berg el al. (1947) found no difference in the performance of laying pullets fed diets containing 0.7, 0.9 or 3.0% calcium for an average of eight weeks prior to the onset of lay. O’Rourke et al. (1952) showed that the phosphorus requirement decreased with age. Using inorganic phosphorus…