Egg Shell Quality III: Calcium and phosphorus requirements of commercial Leghorns

SummaryNo two minerals are more involved in maintaining maximum eggshell quality than calcium and phosphorus. However, determining the optimum quantity of calcium and phosphorus to feed commercial Leghorns has been a continual challenge because the requirement, especially for calcium, appears to be constantly changing. For example the calcium requirement, as indicated by the National Research Council, increased 25% from the 1971 to the 1984 edition. This review presents current calcium and phosphorus recommendations and summarizes the literature showing the progressive changes in calcium and phosphorus requirements as reported by various research workers through the years. The importance of quantity and timing of calcium increase in transition from pullet to layer feed is also discussed.