Radiographical evaluation of bone maturation in Japanese black beef cattle.

Epiphyseal ossification in the radius, ulna, metacarpus, proximal phalanx and tuber calcaneus was examined radiographically in Japanese Black beef cattle. The grade of standard ossification was assessed monthly for each epiphysis. Bone maturations could be divided into 8 grades for the distal radius and distal ulna, 7 grades for the distal metacarpus, 5 grades for the proximal phalanx, and 8 grades for the tuber calcaneus, respectively. The closure of the epiphyseal line completed at the earliest (12-14 months of age) on the proximal phalanx, and at the latest (35-37 months of age) on the distal ulna. Changes in gradings were steep at 0 to 5 months of age but became almost constant after 10 months of age in all the epiphyses. There were no significant differences in bone maturation between the cattle with different sex and breeding conditions.