The article describes the results of the research on the formation of the bone system of the carcasses of purebred and crossbreed steers. Three groups of animals were selected for the experiment by the analog method. The first group consisted of purebred steers of Simmental breed, the second and third groups consisted of ½ blooded steers of Simmental and Charolais beef breeds, respectively. The dynamics of age changes in the skeleton were studied by determining the absolute relative weight and calculating the growth coefficient. The research showed that the absolute weight of the skeleton has increased with the development of the test steers. Thus, if the skeleton mass of newborn steers was 7.44, 7.34, and 8.30 kilos for each group, then at the age of 6 and 12 months, it had increased to 29.2, 29.8, and 30.6 in group 2, 45.8, 45.3, and 46.4 in group 3, and 53.7, 54.2, and 54.6 at the end of the experimental period at the age of 18 months.