USE OF COMPUTERIZED MOTILITY ANALYZER FOR THE EVALUATION OF FROZEN-THAWED RAM SPERMATOZOA

A computerized motility analyzer (CellTrak/S (TM)) was calibrated for its use with ram semen. Adjustment of the several setup variables allo wed an accurate measurement of kinetic parameters such as percentage o f motile cells, straight velocity, curvilinear velocity, linearity and amplitude of lateral displacement of the head. All kinetic parameters , except the lateral displacement of the head, showed significant chan ges after freezing and thawing. The curvilinear velocity exhibited the least significative post-thaw decrease. The alterations in kinetic pa rameters provoked by freezing and thawing could account for the low su ccess obtained with frozen semen by cervical insemination, as it is ac cepted that during the initial steps of fertilization high motility an d linearity are required.