Анотація:
Aims. The purpose of work was to define the selection types of bulls, which admitted to the use in Ukraine, are got as a result of, monitoring of inbreeding. Methods. Conducted the genealogical analysis of Holstein bulls family tree, which admitted to the use in Ukraine in 2011–2012 years (n=934). The coefficient of inbreeding (Fx) was calculated on the formula of S. Write in modification of D.A. Kislovskiy. Results. It is set that 70,9 % bulls got by the crossbreeding and 20,1 % – from a linebreeding. Over 63 % bulls are inbred; 14,8 % is got as a result of complex inbreeding. A middle index of S. Write coefficient on all array of bulls was within the limits of 1,95–1,96 %. Most numerous was a group of bulls, got as a result of moderate inbreeding: 57,7 % – in 2011 year, 56 % – in 2012 year. Part of sires with close inbreeding was within the limits of 12,2 % - 11,9 % from the general quantity of bulles which are admitted to the use. Conclusions. Use of inbreedings with the purpose of increase of homozygosity and fixing of valuable internalss of prominent ancestors expediently on condition of careful genealogical analysis and molecular-genetic control of genetic defects.