Evaluation of breeding bulls based on quality of offspring considering crossing options

Breeding takes the main place in the complex of measures for intensification of dairy cattle breeding. A characteristic feature of breeding work is identification of the most valuable genotypes and their further use in cattle population. The Holstein breed is considered one of the most highly productive breeds, in many countries of the world it is used for the genetic improvement of local breeds. In this regard, a comparative assessment of methods for determining the breeding value of bulls of different genotypes obtained by interbreeding is relevant. The results of assessment of genetic superiority of the used breeding bulls in terms of milk productivity of daughters for the first lactation through interannual deviations of the homogeneous peers are presented, the best producers in all the studied herds are identified, it is established which breeds the best and worst breeding bulls belong to. The research revealed that 18% of bulls had genetic superiority at controlled farms (9% - Holstein breed, 6% - Yaroslavl crossbreeding bulls, 3% - Mikhailovsky type’s bulls), a negative value - 24% including 9% - Yaroslavl crossbreeding bulls, 9% - Mikhailovsky type’s bulls and 6% - Holstein bulls. A comparative evaluation of the two methods showed a high reliable positive correlation between results of Mikhailovsky type bulls and Yaroslavl crossbreeding bulls equal to 0.82 and 0.56, respectively, which indicates a high reliability of the method of genetic superiority index, which can be used to evaluate bulls during crossbreeding. It is possible to increase the genetic potential of herds by excluding producers with a negative genetic index. The obtained results are recommended to be used when mating bulls and for development of breeding programs for individual herds or entire population