Milk yields of 43 419 Black-White and 20 995 Red-White cows and their daugh
ters used in 1978-1993 in the South-West region of Poland were analysed. Br
eeding values of all animals were estimated by BLUP (Animal Model). The dat
a was preadjusted for age and season of calving. Cows-dams were classified
to a group of cows with high performance by two ways: 1. cows recorded in H
igh Performance Register, 2. cows which exceeded an assumed production leve
l ((x) over bar +1.96 s, 1.64 s or 1.28 s, respectively). Breeding values o
f classified dams were higher than those of remaining dams. Similarly, daug
hters of these darns had higher breeding values than daughters of remaining
dams. Greater differences were observed in Black-White breed. Generally, d
ifferences of breeding value in dam group were higher than in daughter grou
p.