The researchers wanted to see how cadmium chloride affects rat sperm movement using a computer system. They took sperm samples, added different amounts of cadmium chloride, and checked the sperm's movement at various times. They found that after even a short exposure, cadmium chloride made the sperm swim less effectively – slower and with less control. The higher the cadmium chloride dose and the longer the exposure, the worse the sperm movement got. This shows that cadmium chloride can harm the ability of rat sperm to swim properly.