Figure 2: SLC-15. The various steps in the preparation of SLC-15 with stallion semen. (a) The first 1.5 mL (the most sensitive) is added from a Pasteur pipette to avoid disrupting the colloid surface and create a sharp interface; (b) The remaining semen is added from a disposable pipette; (c) All the semen has been layered on the colloid (note that the interface between semen and colloid is clearly delineated); (d) After centrifugation, the supernatant is removed by aspiration and the sperm pellet is aspirated using a clean pipette.