Storage & Handling of Frozen Semen
Once semen is frozen, it is essential to store the semen in a liquid nitrogen tank that is in good working order. Understanding how a liquid nitrogen tank works is important to making sure you do not damage your tank. It is also important to understand why a tank needs to be kept as full of liquid nitrogen as possible.
| The Liquid Nitrogen Tank - This is an image of a liquid nitrogen tank for semen storage that has been cut in half. The tank is essentially a super efficient thermos. Between the outer walls are insulation but this space also contains a vacuum that is the main insulating factor. In the center of the tank are canisters that can be loaded with canes as shown in the image or cup-like containers called goblets. Either can be used to store straws of semen. |  |
| The liquid nitrogen is very cold at -196°C. As you go up from the liquid in the tank, the neck of the tank gets warmer until you reach the ambient temperature. |  |
| It is important to keep the nitrogen as full in the tank as possible if you will be removing straws for insemination. The reason is that when raising the canisters up and lifting a cane up to remove straws, the other straws will warm. In a full tank the temperature in straws does not reach a level in which sperm are damaged. However in a tank with low nitrogen levels, the straws warm to damaging temperatures and if repeated pulling up of canisters is done to get more straws, unused straws in the tank will be damaged as the temperature in the top of the tank will warm. |  |
