Stallion Sperm Integrity After Centrifugation to Reduce Seminal Plasma Concentration and Cool Storage for 4 days.

The objective of the study was to investigate if reducing the seminal plasma of stallion extended semen by centrifugation once will suffice to maintain acceptable semen quality for insemination after 4 days of cool storage. Collected semen was extended to 25 × 106 sperm/mL and subjected to one of the following treatments: noncentrifuged (control), centrifuged for 10 minutes at 900 × g and 1800 × g. The supernatant was partially removed, and the sperm pellet, reconstituted and re-extended. It was then placed in a passive cooling device overnight and then transferred to a refrigerator for the remainder of the cooling period. At day 0, 2, and 4, total motility (TM), progressive motility (PM), and plasma (PLM) and acrosomal membrane integrity were assessed. Centrifuged groups had higher TM and PM at day 4 than the control group (P < .05). Likewise, centrifuged groups had higher intact PLM in day 4 (P < .05). A single centrifugation cycle to reduce seminal plasma concentration will suffice to preserve sperm integrity acceptable for an artificial insemination dose up to 4 days of cool storage.

Sperm quality during extra-gonadal sperm reserve depletion in stallions.

To estimate when, during stallions' extra-gonadal reserves (EGR) depletion period, sperm quality would reach its highest quality, six light breed sexually rested stallions were collected daily for 7 days to deplete EGR. On collection days 1, 3, 5, and 7, sperm output, total (TM) and progressive (PM) motility, morphology, and plasma membrane (PLM) integrity were evaluated. Sperm output decreased as EGR depletion advanced, stabilizing on days 5-7. Sperm motility (TM and PM) and morphology were not different during EGR depletion. Plasma membrane integrity improved from day 1 to 3; however, no further improvement observed on days 5 and 7. Sperm of sexually rested stallions reach the highest quality on day 3 of the EGR depletion period.