Involvement of calcium and phosphorus in bone and shell quality of early naturing commercial layers

摘要

Leghorn strains are continuously changing to meet market demands. The age of maturity in commercial pullets has steadily decreased, and egg output and case weights continue to increase. Consequently, nutritional management also needs to change to meet the genetic potential of the new strains. When new genetic lines are introduced, issues such as calcium and phosphorus management need to be constantly evaluated. The loss of marketable eggs as a consequence of poor shell quality and the reduced productivity and increased mortality associated with cage layer fatigue are major factors of economic importance to egg producers. There are several nutritional factors that impact cage layer fatigue and eggshell quality. Although calcium and phosphorus are the major factors, several other factors such as vitamin D_3, chloride, electrolyte balance also impact on eggshell quality (Table 1).