RESUMEN
The aim of this paper was to evaluate semen parameters from Czech Fleckvieh (dual-purpose breed) bulls used in artificial insemination in the Fleckvieh population. The ejaculate was collected from bulls only once a week, which is not usual. Respectively, the effects of age and season of collection on semen parameters were tested. The average volume of ejaculate by Fleckvieh bulls was 8.72â¯mL, which is higher than results in studies of bulls which were collected usually more than once a week. The average total motility was 72.82â¯% and progressive motility was 67.99â¯%. Sperm concentration reached on average 1254.10 × 10 6 ⯠mL - 1 . The total motility of spermatozoa after thawing was 40.88â¯%. A significant influence of age was observed on ejaculate volume, total and progressive motility, and total motility after thawing ( P < 0.05 ). The season of collection had a significant influence on the volume of ejaculate, total motility, progressive motility, concentration of spermatozoa, and total count of spermatozoa ( P < 0.01 ).