BREEDING VALUE OF HEREFORD BULLS
The objective of the research was to study different methods of Hereford linear bulls assessment in a comparative aspect, in order to characterize their breeding value. The technical method of comparing and using the mean standard deviations for each group of linear animals and for the herd in general has been used in the JSC “Poultry Farm “Chelyabinskaya”, Chelyabinsk region, in the period of 2008-2018. The degree of discreteness (difference), as regards the whole cattle herd by the set of economically valuable traits, has been calculated for a single group of cows. The bull - sires have been assessed by the quality of their offspring, using the traditional evaluation method of their offspring's performance, as well as taking into account the genotype of their sons by the GDF5 gene-marker. The distribution of groups of test bulls by the GDF5 marker genotypes made it possible to enhance the differentiation between the genotype carriers. It is concluded that the method of determining the degree of consolidation (discreteness) of the created groups of breeding Hereford cattle will increase the effectiveness of the desired genotypes formation in the process of genomic selection