Processes of cryopreservation consists of three steps: dilution with the extender/cooling (Step 1), addition of cryoprotectant (Step 2), and freezing/thawing (Step 3) and spermatozoa are exposed different kind of environment and stress in each step. We categorized sperm samples as good freezablitiy (GF), damaged by cryoprotectant (DCP), and damaged by freezing (DF) and identified characteristics of each group in different step of cryopreservation. In Step 2, DCP was significantly decreased in motility, rapid speed and increased in slow speed. DF was significantly decreased in only motility whereas there were no significant difference between GF and DF and significantly higher than DCP in Step 2. Motility, rapid, medium speed of all group were significantly decreased in Step 3 and GF was significantly higer than other groups. AR pattern of all groups were significantly increased in Step 3 whereas GF was significantly lower than other groups. Additionally AR pattern of DF was significantly increased in Step 2. F pattern of DF and DCP were significantly decreased in Step 3. There no difference of B pattern in whole process. Mitochondrial activity of DCP was significantly decreased in Step 2 and mtichondrial activity of all groups were significantly decreased in Step 3. However mtichondrial activity of GF was higher than other groups. Viability result shows same significant difference with mitochondrial pattern. The present study compared with various sperm parameters in different groups which has different freezability. We defined different two types of group that damaged from different step of cryopreservation. DF and DCP is mainly damaged in Step 3 and Step 2 respectively. The results of current study suggest that various sperm parameters can be used as physical markers in freezability.

• Sung-Jae Yoon(Department of Animal Science and Technology, Chung-Ang University, Anseong 456-756, Gyoenggi-Do, Korea)
• Md Saidur Rahman(Department of Animal Science and Technology, Chung-Ang University, Anseong 456-756, Gyoenggi-Do, Korea)
• Woo-Sung Kwon(Department of Animal Science and Technology, Chung-Ang University, Anseong 456-756, Gyoenggi-Do, Korea)
• Amena Khatun(Department of Animal Science and Technology, Chung-Ang University, Anseong 456-756, Gyoenggi-Do, Korea)
• Ye-Ji Kim(Department of Animal Science and Technology, Chung-Ang University, Anseong 456-756, Gyoenggi-Do, Korea)
• Do-Yeal Ryu(Department of Animal Science and Technology, Chung-Ang University, Anseong 456-756, Gyoenggi-Do, Korea)
• Myung-Geol Pang(Department of Animal Science and Technology, Chung-Ang University, Anseong 456-756, Gyoenggi-Do, Korea)