Abstract
Bone age was surveyed in a total of 470 foals and young growing horses ranging from 0 to 24 months of age. When 2 820 radiographs were obtained, 181 of them were found to show radiographic changes. It is the purpose of this report to present some features of these changes together with etiological discussion. The distribution of the 181 cases of radiographic changes was surveyed. In addition, 17 cases were traced as required. As a result, it was estimated that a longitudinal shadow picture at the apical site of the proximal sesamoid bone, a shadow picture like avulsion at the apical site of the proxical sesamoid bone, a shadow picture like avulsion at the caudal site of the ossification center of the calcaneal bone and a shadow picture like bone cyst at the ossification center of this bone were physiologic pictures found in the growing process. On the other hand, it was estimated that osteoporosis of the proximal sesamoid bone, luxurious callus at the basal site of this bone, exostosis at the distal lateral site of the 3rd metacarpal bone, osteoporosis of this bone and the 1st phalanx, epiphysitis at the distal medial site of this bone, epiphysitis at the distal medial site of the radius, and luxurious callus at the proximal dorsal site of this bone and at the dorsal site of the tarsal bone were abnormal changes of bone disease.
