Influence of the inbreeding level on the genomic assessment of Holstein bulls of different genealogical complexes

The studied 338 bulls of the new generation of US selection belong to the previously identified genealogical complexes (branches) of H.H.С. Manfred (Mf), B.M.T. Cleitus (Cl), Prelude (Pr)in the W. Ideal line and Blackstar Emori (BE), Magic (Mg), Adam (Ad) and G. Arlinda Chief (AC) in the R. Sovereign line. The influence of genetic factors: father, line, branch and level of inbreeding on the Genomic Estimation of Breeding Value (GEBV) for the productive qualities of young bulls was studied. On average, the inbreeding coefficient of the studied livestock is 13.14±0.15 from 12.72±0.54 to 15.98±1.26%, the genomic estimate for milk yield varied from 1204±101 to 1571±198 kg with an average value 1308±27 kg of milk.A significant weak positive correlation between the genomic assessment of bulls for milk yield and the inbreeding coefficient was revealed (r = +0.118, p?0.95).Differences in the GEBV of milk productivity traits between groups of bulls of different genealogical complexes are not significant. Significant differences in inbreeding coefficients only between Cl and AC (–3.08%, p?0.95), Ad and AC (–3.06%, p?0.95), BE and AC (–3.26%, p?0.95). Using one-way analysis of variance (ANOVA), a large influence on the genomic breeding value was established by the factor inbreeding coefficient - 42.4% for milk yield, 53.6% for fat content and 58.9% for protein content, which is comparable to the influence of the father on the GEBV for milk yield 42.6%, fat and protein content 50.8 and 46.0%, respectively.