Anotace:
The objective of this study was to analyse eight milk yield and longevity traits in dependence on feeding (grazing) system. Data of purebred Slovak Spotted dairy cows (35,812 heads) culled in the period between 2006 and 2019 were evaluated. Only herds those feeding (grazing) system was known were taken into account. Dairy cows were assigned to four groups: (1) heifers not grazed, cows not grazed (17,628 heads), (2) heifers grazed, cows not grazed (13,056 heads), (3) heifers not grazed, cows grazed (156 heads) and (4) heifers grazed, cows grazed (4,972 heads). The highest average 305-day milk yield (6,139.22 kg) and lifetime milk yield (18,606.78 kg) were found in animals of group (1). Contrariwise, longevity traits were found more favourable in animals of group (4). Their productive life was by 102.78 days longer and average parity was by 0.14 higher in comparison to group (1). The differences between groups were found significant.