Effects of Dietary Calcium Levels on Egg Production and Bone Structure of Pheasants

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Abstract
Captive pheasant (Phasianus colchicus) hens fed various levels of calcium produced more eggs when the amount of calcium in the diet was increased. Birds on high calcium diets would have been able to produce two adequate sized clutches of eggs; birds which had received very little dietary calcium (0.5 percent) could not have produced two clutches. The amounts of calcium, phosphorus, and ash found in femurs varied little between birds fed different levels of calcium. Osteoporosis was detected in female pheasants fed low levels of calcium. Femurs of these birds had enlarged haversian canal systems, as shown by total space occupied by canals, mean canal size, and the amount of cortex present. Bones of birds fed 0.5 percent and 3.2 percent calcium were significantly different in these respects; inconclusive data were obtained from birds fed intermediate levels of calcium. Cocks on low calcium diets showed some evidence of osteoporosis; those receiving adequate calcium showed none. Recent studies have shown that pheasants can select calcium grits when unusual needs arise; thus pheasants might get enough calcium during the breeding season even in low-calcium habitat. To determine whether calcium supplies are adequate it is suggested that breeding females from areas of low populations be examined for evidence of osteoporosis.

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