Storage Temperature of Frozen Semen

Storage temperature of frozen semen using liquid nitrogen (LN₂) is:

Correct Answer: –196°C

Frozen semen is stored in liquid nitrogen (LN₂) at –196°C, which is the boiling point of liquid nitrogen. At this ultra-low temperature, all biological activity (including metabolism and enzymatic activity) is suspended, allowing virtually indefinite storage of spermatozoa.

Key Temperature Points in Semen Handling

• Storage temperature: –196°C (in liquid nitrogen)
• Dry ice temperature: –79°C (used for short-term semen transport)
• Thawing temperature: 37–40°C for 30 seconds

Cryogenics in Semen Processing

• Most commonly used cryogen: Liquid Nitrogen (LN₂)
• Most commonly used cryoprotective agent: Glycerol (protects sperm from ice crystal damage during freezing)
• Semen is typically processed into mini-straws (0.25 ml) or maxi-straws (0.5 ml) before freezing.