Antler growth and osteoporosis II. Gravimetric and chemical changes in the costal compacta during the antler growth cycle

In an attempt to support the morphological data indicating a cyclic physiological osteoporosis in three three‐year‐old captive Rocky Mountain mule deer, costal cortical biopsy material was analyzed by densitometric and chemical methods. Bone densities, amount of ash per unit volume and levels of calcium, phosphorus and magnesium per unit volume indicated bone mineral was mobilized during periods of antler growth. However, calcium to phosphorus ratios were maintained at normal levels during this reversible cyclic phenomenon. These data substantiated the morphological observation of a cyclic physiological osteoporosis in the mule deer.