Variability & heredity of breeding value index of Ayrshire and Holstein bulls in Finland

To define the breeding value of bulls, whose parameters in different populations require further research, is the main problem in dairy cattle selection. The aim of our work was to study the variability and inheritance of breeding value index of bulls defined by the BLUP method. We used the information on the breeding value index of 2559 bulls of Ayrshire and Friesian (Holstein) Finnish breeds for the years 1995-2006. High variability of a breeding value index of Ayrshire bulls was revealed; their index mark varied from 26,8 to -28,6 points, while the average rate in the division was 3,9 ± 0,3 points. The best group of bulls, with the breeding value equal to 12 points and more, made up -28,6 %. The share of leader bulls with very high breeding value (24 points and more) was 3,1 %. On the whole, neutral bulls and improver-bulls amounted to 64,1 %, degrader-bulls - 35,9 %. To valuate the inheritance of breeding value index we used father groups and the calculation of correlation coefficient in father-son line. We found the inherited father’s influence on their sons; the correlation coefficient of Ayrshire bulls was 0,263 (P