Comparison of fertility traits of Slovakian Pied breed, black and white breed and their crosses

Fertility traits are compared in cows of Slovakian Pied breed, holsteinized Black and White breed and their crosses from combination and absorptive crossing. A total of 10,896 records from the 1st to the 3rd lactations were analyzed by the least-squares method. A model of analysis of covariances contained the fixed effects herd, year of calving, genotype group (Slovakian Pied breed was analyzed without this effect), and concomitant variables milk production over 305-day current lactation and duration of insemination interval (the indicators insemination interval, days open and calving interval without this variable). The worst values of fertility traits were determined in the Ist lactation (Tab. I). Slovakian Pied dairy cows had a statistically highly significantly shorter days open in all lactations (P < 0.01) in comparison with Holstein cows (by 12.5; 15 and 13 days for lactation number 1 to 3). The Slovak breed had a statistically highly significantly (P < 0.01) longer period of pregnancy (according to lactation number by 5.3; 7.2 and 5 days). The genotype groups of the Black and White cattle (crosses with different blood proportions of the Slovakian Pied and Holstein breeds) showed smaller differences in the indicators, and except the length of service period in the second lactation and the calving they were insignificant.