The scientists looked at proteins in ram sperm to understand what happens when the sperm is frozen. They checked where three proteins were in fresh and frozen sperm, and when sperm were put under certain conditions. They found that frozen sperm had fewer of these specific proteins than fresh sperm. After being put through certain processes, the proteins shifted in their location on the sperm. They think that two of these proteins may be useful in predicting sperm fertility and freeze-ability.