The experiment was based on feeding the organic and inorganic forms of selenium and the assessment of their effects on the laboratory values of the ejaculate (total count of sperm, sperm motility, ejaculate volume, sperm concentration and per cent of pathological sperm) in breeding boars. The experiment involved 18 boars breed Duroc divided into two equal groups. The individual groups received feed mixtures with the supplement of 0.6 mg Se/kg of feed mixture in organic form, and 0.6 mg Se/kg of feed mixture in inorganic form. The experiment lasted 20 weeks.
The group of boars receiving the inorganic selenium supplement of 0.6 mg/kg of feed mixture had a lower sperm concentration (P < 0.05); however ejaculate volume increase (P < 0.05) occurred at the same time. In our experiment the groups of boars receiving the selenium supplement of 0.6 mg/kg of feed mixture in both organic and inorganic form had the most equal values of the total count of sperm produced. Selenium in organic form (higher dose) may improve semen quality in breeding boars.