INFLUENCE OF GENETIC FACTORS ON INDICATORS LIFETIME PRODUCTIVITY OF DAIRY CATTLE

Researches results of cows of the Ukrainian Red-and-White lifetime productivity dairy breed on traits of duration of economic use within the limits of an estimation of crossbred genotypes and genealogical formations are resulted. Reliable influence of the conditional share of Holstein breed heredity on the economic use duration and lifetime milk productivity of cows has been established. For the longest time in the herd, crossbred cows with Holstein bloodline of 25.0 % and crossbreeds with heredity of the parent breed up to 50.0 % were used. At the final stage of crossing in animals with blood ratio of 62.5-87.5 %, a noticeable reduction in the duration of economic use was observed. Animals with Holstein bloodlines of 75.0 and 87.5% were inferior to groups of crossbred cows with heredity of 25.0 and 50.0% with reliable difference of 590 and 633 (P<0.001), 432 and 475 (P<0.001) days, respectively. At the same time, from cows with a share of Holstein blood of 87.5 %, the highest lifetime milk yield was obtained with an excess of cows groups of other genotypes by 1250-3260 kg of milk with reliable difference compared to crossbred genotypes with bloodness - 25.0 % (P<0.001), 37.5 (P<0.001), 50.0 (P<0.01) and 62.5 % (P<0.05). The hereditary influence of lines on the indicators of lifetime productivity in intralinear selection and in some variants of interlinear combinations was proved. The influence of genealogical formations on longevity indicators in in-line selection was evidenced by reliable difference between the extreme variants of the assessed lines on the basis of economic use (651 days; P <0.001) and liftime milk yield (14267 kg; P <0.001). According to the results of interline selection in different variants of paternal and maternal lines combinations, significant variability of the offspring obtained from these variants was established, according to the estimated traits of duration of use and lifetume milk production. Cows obtained in all variants of interlinear selection of parental lines Enhancer, Hannover and Valiant with sires of maternal line S. Cavalier have always had high indicators of duration of economic use and lifetime milk productivity.