The Effect of the Pre-Laying Level of Calcium on the Performance of White Leghorn Pullets

CONSIDERABLE information has been recorded in the literature concerning the calcium reqirements of chicks for growth and bone development, and of laying hens for maintenance and egg production. Bethke, Kennard, and Kick (1929) obtained maximum bone ash and growth to four and eight weeks of age with 0.858 percent calcium and 0.442 percent phosphorus. Wilgus (1931), found the minimum level of calcium for growing chicks to 16 weeks of age to be 0.66 percent when the Ca:P ratio was in a range of 1.0:1 to 2.2:1. Other investigators including Hart, Scott, Kline, and Halpin (1930); Couch, Fraps, and Sherwood (1937); Nowatarski and Bird (1943); and Carver, Evans, and McGinnis (1946) have shown that the requirement of the growing chick for calcium is very definitely dependent upon the level of phosphorus and vitamin D in the ration. The quantitative level of dietary calcium required by the laying hen as set forth . . .