Effective standardization of bovine frozen semen sperm motility analysis in a multi-laboratory setting.

Sperm motility is the only functional parameter that is part of basic semen analysis, and its results have important implications for clinical practice and the production of semen doses for artificial insemination. However, substantial variations in sperm motility analysis within and across laboratories have been reported. The objective of the present study was to evaluate the precision and accuracy of sperm motility analysis in a controlled, multi-laboratory setting. Ten batches of conventional and sexed bovine frozen semen were produced, with three replicates of the same batch coded with different identification numbers. Sperm motility evaluations were performed using computer-assisted sperm analysis (CASA) systems by nine technicians across six laboratories, during three test periods conducted over one year. The overall intra-technician CV was 14.7 % for conventional semen and 13.9 % for sexed semen. Bland-Altman plots showed that the mean differences of individual test results from the overall mean were close to zero (-0.4-1.1 %), with most differences (61.5 %) ranging between ± 5 %. In conclusion, precise and accurate sperm motility results were obtained by qualified technicians when following standardized procedures and utilizing CASA systems.