Genetic potential of seed bulls of the domestic dairy breeds of the Vologda oblast

The problem of preserving the gene pool of domestic breeds of dairy cattle is currently aggravated. In order to study the available genetic resources and improve the domestic breeding cattle's competitiveness, the characteristics of selection and genetic parameters of productive traits of dairy populations of the Kholmogorskaya and Yaroslavskaya breeds of the Vologda Oblast were carried out. Based on the calculation of selection and genetic parameters of productive traits in the Kholmogorskaya and Yaroslavskaya breeds populations the following variability coefficients (CV) are established, on milk yield - 22.0%, 17.7%, on mass fraction of fat - 11.8%, 6.5%; on milk yield heritability (h2) 0.71, 0.67, on mass fraction of fat for Kholmogorskaya breed's mothers - 0.56 with confidence (P≤0.001), giving an idea of the possibility of successful selection and further dairy cattle improvement. The power of influence of seed bulls of the Kholmogorskaya and Yaroslavskaya breeds on the indicators of daughters' milk yield (η²) is defined - 0.36,0.26, on fat yield - 0.14, 0.11 with high degree of reliability (P≤0,001). The authors established high-confidence influence of “genealogical line” factor (P≤0,001) on the breeding value of the Kholmogorskaya and Yaroslavskaya breeds bulls on milk yield of maternal ancestors η² = 0.83, η² = 0.85; on milk fat content - the influence is unreliable. Domestic seed bulls have high breeding value for maternal ancestors' milk yield and mass fraction of fat. The best realization of genetic potential of the Kholmogorskaya and Yaroslavskaya lines' bulls on milk yield varies from53.6 to 83.7%, of Holstein lines' bulls - from 42.4 to 67.5%. to preserve a gene pool of domestic breeds it is necessary to use the Kholmogorskaya and Yaroslavskaya breeding bulls taking into account that their genetic potential is more fully realized by daughters in the conditions of breeding farms of the North West Region of the Russian Federation.