The aim of this study was to investigate: (a) seminal plasma protein content in the Land-race (n = 38), Large White (n = 44) and Duroc (n = 24) boars breed, as well as boars distribution according to protein content in seminal plasma, and (b) the sperm motility in the semen samples, forming from the ejaculates with high or low protein content, stored in vitro on 17°C for 3 days. Not significant (p > 0.05) differences was found in seminal plasma protein content between three boar breeds. Only 31% of the 106 investigated boars had > 3.6% protein in seminal plasma. Progressive motility was significantly higher (p lt 0.01) in the ejaculates with high, compared to the ejaculates with low protein content (82% vs. 76%). After 3 days of storage, in thel:4 dilution proportion, the average progressive motility was significantly (p lt 0.01) decreased in relation to this value in native semen from the boars with high (82% to 64%), as well from the boars with low protein content in seminal plasma (76% to 48%). However, the average diluted semen progressive motility was significantly greater (p lt 0.01) in the boars with high (64%), compared to the boars with low protein content in seminal plasma (48%). The number of good diluted semen samples (>65% progressive motility), was also significantly (p lt 0.01) greater in the boars with high (41%), compared to the boars with low protein content in seminal plasma (12%)
