FERTILITY OF COWS OF THE SLOVAKIAN PIED BREED, BLACK PIED BREED AND OF THEIR CROSSBREDS

Some fertility traits were evaluated in cows of the Slovakian Pied bre ed (S), Black Pied breed (L) and crossbreds from grading up (F11, F111 and F111 generation) by LSM method. The significant influence of the herd and year-season factors on the fertility traits was confirmed. We noticed also differences of fertility traits between parities with th e best fertility in 3rd parity. There were no statistically significan t differences between the crosses from the grading up and cows of the Black Pied breed in the observed traits (days open 120.85 or 120.8 day s). Better fertility was observed in cows of the Slovakian Pied breed (days open 108.97 days), however, with lower efficiency (by 1300 kg du ring one lactation) compared with cows of dairy type. Statistically hi ghly significant regress coefficients show the increasing milk product ion influences the fertility traits negatively.