A microcomputer-photographic method for evaluation of motility and velocity of bull sperm.

A semiautomated computerized system analyzed 35-mm negatives obtained from dark-field microscopy and determined velocity of each sperm and percentage of motile sperm in the sample. Precision and accuracy of the system for percentage of motile sperm were evaluated in comparisons with track motility and videomicrography. Motility was evaluated at four times during processing for cryopreservation or after thawing. Based on the 95% confidence intervals for percentage of motile sperm, computer and track motility evaluations were more precise than videomicrography. Computer and track determinations of the percentage of motile sperm were correlated with the ratio of live to killed sperm in prepared mixtures. The computer system was reasonably precise and accurate. Correlations of spermatozoal velocity or motility with fertility were studied. The competitive fertility index, based on semen from nine bulls, was correlated with the computer-determined percentage of motile sperm at 0 to 1.5 h after thawing, velocity, or the combination of motile sperm and velocity. Such a computerized system may aid in prediction of fertility.