Correlation of growth parameters to the growth periods among the replacement heifers

In Sverdlovsk region the Ural type of Holsteinized black-and-white cattle is raised and used. Admixing of Holstein line revealed a number of problems in the breeding of crossbred livestock, including decrease of the cows’ productive longevity. This poses new challenges for solving the issues of the herd reproduction and growing of young replacement livestock. The research of correlation between the dynamics of live weight gain by periods of growth along the young livestock lines is relevant and has practical significance. In result of the research it was found that the heifers of Vis Back Ideal 1013415 line outcompeted their peers from the Reflection Sovering line 198998 in terms of live weight in all periods, provided that they were raised under the same conditions, same feeding and same care; moreover all heifers had practically the same live weight at birth. At 6, 10 and 12 months of age, the difference in live weight was significant at p ≤ 0.05–0.01 in favor of heifers of the Vis Back Ideal 1013415 line. According to the periods of growth, a positive conjugation of body weight changes was revealed. The correlation between live body weight by periods and the age of the first insemination is negative. 