Weanling rats were fed diets containing raw lyophylized hand-deboned shank beef (HDS) supplemented with CaCO3, retorted lyophylized mechanically deboned shank beef (MDS), or raw lyophylized MDS. Ca in the latter two diets originated from bone during the mechanical deboning process. Ca absorption, Ca retention, bone weight, and bone breaking strength were similar for comparative dietary levels of Ca regardless of the source. Bone ash and Ca content was significantly higher (P < .05) in the MDS 393 (3.93 g Ca/kg diet) diet and in the retorted MDS 460 diet compared with the HDS 488 diet. Relative biological values for the MDS diets calculated relative to the HDS diets ranged from 102 to 132 when the linear regression of Ca consumed, Ca retained, or dietary Ca level vs bone ash or bone Ca content was obtained. The retorted MDS 460 diet contained the highest Fe level and exhibited a lower percent absorption, terminal hemoglobin level, and liver Fe storage. Humerus F content increased as dietary F (also present from bone) level increased. Dietary F level did not determine humerus breaking strength.