Colloidal Centrifugation of Stallion Semen: Changes in Sperm Motility, Velocity, and Chromatin Integrity during Storage

The current study investigated the changes in sperm quality (motility, velocity, and chromatin integrity) occurring during storage at room temperature or 5°C for up to 48 hours in spermatozoa after extension or single-layer centrifugation (SLC) through Androcoll-E. In unselected samples, all parameters of sperm quality deteriorated significantly during storage (P < .01), although the deterioration was faster at room temperature (22–30°C) than for cool storage (P < .01). The SLC-selected spermatozoa had higher motility, velocity, and chromatin integrity than the overall unselected population (motility: selected 85 ± 10%, unselected 56 ± 13%; P < .001; velocity: selected 85.1 ± 13 μm/second, unselected 63.5 ± 15 μm/second; P < .001; and DFI selected 12.2 ± 4.8 μm/second, unselected 23.6 ± 7.4 μm/second; P < .001). Furthermore, sperm quality did not deteriorate with storage in the SLC-selected samples, either at room temperature (22–30°C for 24 hours) or cooled to 4°C (for at least 48 hours), whereas a significant deterioration in sperm quality was observed in the unselected sperm samples (P < .01). Thus, room temperature storage of SLC-selected spermatozoa may be an option for insemination doses from stallions whose spermatozoa do not tolerate cooling. In addition, a new sperm analyzer, the Qualisperm, showed good correlation with subjective motility assessment (r = 0.8, P < .001), was user-friendly, and provided a reasonable volume of data. This instrument may be a useful adjunct to sperm quality assessment at the stud.