Depletion of Femur Bone Mineral after the Onset of Egg Production in a Commercial Strain of Leghorns and in Broiler-Type Pullets

INTRODUCTION THE literature contains considerable evidence, both direct and indirect, supporting the partial resorption of skeletan mineral during egg shell formation in the avian species. Cox and Balloun (1971) reviewed some of the related literature. Hurwitz and Bar (1969), have stated that, in their opinion, the function of bone in supplying calcium to the egg shell has been considerably overestimated. The evidence presented by Cox and Balloun (1970) and that presented by Taylor (1961), does not support this opinion. One possible explanation for this lack of agreement is the differences in the period of the hen’s reproductive cycle investigated. This report is an extension of our previous paper (Cox and Balloun, 1970) and contains the results from two experiments to study the utilization of femur bone mineral after onset of egg production in commercial strains of pullets. MATERIALS AND METHODS Physiological factors studied on individual birds were 140-day body weight,…