GROWTH AND DEVELOPMENT OF RED STEPPE STEERS AND THEIR HYBRIDS OF DIFFERENT GENERATIONS WITH HOLSTEINS
The purpose of the research was to study the dynamics of growth and development of Red Steppe steers and the hybrids with Holsteins. To obtain the experimental young cattle, insemination of the full-aged Red-Steppe cows and their half-blooded hybrids with Holsteins was carried out. The obtained offspring was used to form experimental groups with 15 steers in each of them: Group I included Red Steppe steers, Group II - 1/2 Holstein × 1/2 Red Steppe hybrids, Group III - 3/4 Holstein × 1/4 Red Steppe hybrids. It was established that the effect of crossing had been observed in the hybrids' live weight already at their birth. Owing to this, the Red Steppe steers were inferior to Holstein hybrids of the 1-st and 2-nd generation in this parameter by 5.3 kg (20.5%, P<0.01) and 15.6 kg (9.3%, P<0.01), at the age of one year, respectively, by 22.4 kg (7.2%, P<0.01) and 23.7 kg (7.6%, P<0.001), at the age of 15 months - 27.8 kg (7.1%, P<0.01) and 28.0 kg (P<0.01), at 18 months - 33.0 kg (7.1%, P<0.001) and 32.1 kg (6.9%, P<0.001). There were revealed intergroup differences in exteriors in all age periods: purebred steers were inferior to the crossed ones in height at the withers by 1.2-1.7 cm (1.6-2.3%), the height in the sacrum - by 1.2-1.4 cm (1.5-1.6%), the oblique length of the trunk - by 4.1-3.9 cm (6.2-5.9%), the chest circumference behind the scapula - by 3.9-4.8 cm (5,1-6,3%), the semi-grip of the back part was inferior by 1.9-2.8 cm (3.6-5.3%). The intergroup differences in body measurements conditioned the difference in body build indices.