Influence of steer genotypes on the features of muscle development in the postnatal period of ontogenesis

Abstract

Abstract The study of the carcass muscles development was carried out on Simmental and Kazakh White-Headed steers and their first generation hybrids. At the age of 18 months, the control slaughter of 3 steers of different genotypes was carried out: I - Simmental, II - Kazakh White-Headed, III - 1/2 Kazakh White-Headed x 1/2 Simmental. To study the development of muscle groups and individual muscles by anatomical regions, the left half-carcasses were prepared, taking into account the methodical instructions. To facilitate the analysis of the material, the muscles were grouped according to the relevant joints and the topographic location by the generally accepted pattern. The muscles development was studied using the data on the absolute mass of individual muscles and muscle groups. It was established that the steers of group III surpassed those of groups I and II in the total muscle mass of the spinal column, which was 1.28-0.45 kg (10.85-3.56%), the total muscle mass of the shoulder girdle - 1.45-0.51 kg (9.78-3.51%), thoracic limb - 0.72-0.25 kg (9.77-3.43%), pelvic limb - 3.16-1.11 kg (9.78-3.45%) and, in general, throughout the half-carcass of the muscles considered - 6.62-2.33 kg (9.79-3.44%).