Assessment of motility of ejaculated, liquid-stored boar spermatozoa using computerized instruments

Visual-motility assessment is a tool used to determine the quality of boar ejaculates. This method is subjective by nature, and consequently, computer-assisted sperm analysis (CASA), with different software designs, has been developed for more objective assessment using conventional image analysis or particle counting. In the present study, we compared the results of sperm analysis using a conventional CASA system (Cell Motion Analyzer, SM-CMA™), with those using a novel software (QualiSperm™) and those of visual assessment performed by two operators. Ejaculates were collected weekly from four Swedish Landrace boars for 4 weeks. Each ejaculate was divided into three aliquots of different sperm concentration (300, 125, and 40 million spermatozoa/mL) and stored at ∼17 °C for 96 h. Only samples at 40 million spermatozoa/mL concentration were analyzed using both automated systems; for the remaining concentrations, the SM-CMA™ was not used due to its inability to examine higher sperm concentrations. The number of spermatozoa analyzed was highest for the QualiSperm™ (∼300-5000 spermatozoa), followed by the SM-CMA™ (∼200 spermatozoa), and lastly, by subjective motility evaluation (∼100 spermatozoa). There was a time-course decrease in motility of the liquid-stored semen, detectable by either computerized method. Although the percentage of motile spermatozoa measured by the two automated systems correlated well (r ≥ 0.75), there was disagreement between operators. In conclusion, because of the lower degree of variation, the numbers of spermatozoa analyzed, and the speed of analysis (∼1 min per sample), QualiSperm™ appears to be a suitable instrument for routine work, provided it maintains stability and is available at an affordable price.