Influence of Increasing the Calcium and Magnesium Content of the Drinking Water on Performance and Bone and Plasma Minerals of Broiler Chickens

Calcium and magnesium contents of drinking water for broiler chicks were adjusted by additions of calcium and magnesium to provide levels of 0, 25, 50, 75, or 100 ppm Mg and 0, 50, or 100 ppm Ca, arranged in a factorial design. During a 3-week trial, increasing the water magnesium concentration significantly (P less than .05) improved feed efficiency and significantly (P less than .05) increased the incidence of swollen hocks and shortened tibia but had no effect on other measures of performance. Bone ash and bone mineral content were not significantly affected by the calcium treatment. However, increasing magnesium level to 100 ppm significantly (P less than .05) increased bone magnesium and phosphorus levels. Plasma minerals were not affected by these same water treatments.