Influence of dietary calcium and phosphorus on metabolism and production in laying hens.

1. The effects of different dietary concentrations of calcium (24 to 56-9 g/kg) and phosphorus (4-5 to 14-2 g/kg) on production and some aspects of metabolism were studied in laying hens. 2. Treatments did not affect egg numbers, food consumption, conversion efficiency of food to egg, bodyweight gain or mortality. 3. Increasing dietary calcium (Ca) significantly increased plasma Ca and inorganic phosphorus (P), breaking strength at the radius and egg specific gravity and significantly decreased plasma alkaline phosphatase and egg weight. 4. Increasing dietary phosphorus increased plasma P and decreased egg specific gravity significantly. 5. Plasma Ca, P and alkaline phosphatase and radius breaking strength were suitable indices of the Ca status of the hens.