PROTEIN, CALCIUM, AND PHOSPHORUS REQUIREMENTS OF FORCE MOLTED WHITE LEGHORN LAYERS

Two experimental were conducted to determine the crude protein (CP), c alcium (Ca) and phosphorus (P) requirements of 660 chemically force mo ulted pure line White Leghorn layers for a period of 140 d (74 to 94 w eeks of age). Hens (69 weeks of age) were moulted by feeding excess zi nc (15,000 ppm) for 10 days, followed by ground yellow maize for 25 da ys. In both the experiments, normal layers (nonmoulted) of the same gr oup were used as control. The levels of CP tested in Experiment 1 were 16, 18 and 20%. While in Experiment 2, three levels of Ca (2.75, 3.25 and 3.75%) were used with two levels of P (0.50 and 0.65%) in a facto rial manner. In Experiment 1, hen-day egg production was significantly (P less than or equal to 0.05) higher with 20% dietary CP compared to the 16 and 18% dietary CP, while body weight gain, feed efficiency, e gg weight and albumen quality showed no difference between the groups fed 18 and 20% CP diets. In Experiment 2, moulted layers produced sign ificantly more number of eggs with better shell quality and improved f eed efficiency than their nonmoulted counterparts. Dietary levels of 3 .25% Ca and 0.65% P were found to be optimum for better performance of hens during post moult phase interms of hen-day egg production, feed efficiency, shell per cent, shell thickness and tibia ash content. Whe reas, egg weight, and serum calcium and inorganic phosphorus were not influenced by dietary Ca and P levels.