GENETIC VARIABILITY OF HOLSTEIN CATTLE ASSESSED BY PEDIGREE ANALYSIS

The aim of this paper was to evaluate the genetic variability within Holstein cattle population in Slovakia usingthe methods of pedigree analysis. Totally, 76,176 animals were included into the reference population. Pedigreecompleteness assessed by index of pedigree completeness was satisfying; the proportion of known ancestorsin the first three generations was over 95 %. The value of average inbreeding coefficient was not alarming (0.95 %), but regular increase of average inbreeding was observed in recent years (R2 = 0.963). The difference between the effective number of founders and the effective number of ancestors showed unequal contributions of individuals into reference population caused by the bottleneck effect. Very low effective numbers of founder genomes reflected the loss of founder gene pool within the population. Regular monitoring of genetic diversity is an essential part of breeding work within the population. Farmers should focus on appropriate mating strategies, e.g. individual mating programs limitinginbreeding.