Seminal plasma removal by density-gradient centrifugation is superior for goat sperm preservation compared with classical sperm washing

Seminal plasma removal is routine in goat sperm cryopreservation protocols. The classical washing procedure designed to accomplish this usually leaves the pellet resulting from use of this procedure contaminated with dead sperm, debris, and cells other than sperm. This contamination negatively affects viability of sperm after cryopreservation. The present research was conducted to compare the effect on chilled and frozen-thawed goat sperm of the classical washing method to that of a selective washing method involving density gradient centrifugation (DGC). In the first experiment, sperm variables were measured in freshly collected sperm, and again after its washing with both methods and chilling at 5°C for 0, 3, 24, 48, 72 or 96h. The DGC-washed sperm had greater (P