The present study investigates the intensity of muscle growth in various anatomical parts of carcasses in Black-and-White heifers and their crosses with Hereford and Charolais breeds. It was established that muscle growth exhibits significant variability, influenced by functional load, genetic factors, and the ontogenetic stage. The most intensive growth was observed in the abdominal musculature, where muscle mass increased by 25.97 times by 18 months of age, significantly exceeding the overall growth rate of carcass muscle mass (16.08). This is attributed to increased functional load, caused by the age-related increase in visceral organ mass and the development of ruminal digestion. Muscles connecting the trunk to the thoracic limbs also exhibited high growth rates, performing functions of trunk support, involvement in locomotion, and counteracting gravitational pull. Large muscles of the pelvic girdle and thigh area, such as the middle gluteus and biceps femoris, were characterized by high power and significant absolute mass, ensuring the extension of the pelvic limbs and generating propulsive thrust. Comparative analysis revealed that the musculature of the axial skeleton (abdominal wall, thoracic cage, vertebral column) grew with positive allometry, while peripheral musculature exhibited negative allometry. By 18 months of age, the relative mass of axial musculature reached 51.87 %, exceeding that of peripheral musculature (48.13 %). The findings highlight the importance of considering functional and genetic characteristics of muscle growth for an objective assessment of the meat quality of various anatomical parts of carcasses.