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.