Frozen semen is frequently damaged during handling after thawing and prior to insemination. Thermic shock is the permanent injury to sperm cell caused by a sudden decrease in post-thaw semen temperature.

Several studies have shown that temperature changes due to different circumstances such as low nitrogen level, a poor canister manipulation, or a mishandling of semen before and after thawing affect the motility and integrity of the semen.

Thaw unit
Always check the temperature in the thaw unit before pulling a frozen straw from the storage tank. Be sure the water is clean and the thawing device is calibrated at the right temperature.
Calibrate the thermometer used for monitoring thaw water temperature on a regular basis.

Semen storage tank
Nitrogen Level: Low nitrogen level affects the morphological structures and viability of the sperm cell. Be sure to check the level of the liquid nitrogen in your storage tank.

Canister manipulation: The canister must be raised up to the frost line of the storage tank when locating a straw of semen. After taking the cane of the bull that you are looking for, lower the canister to the bottom. This procedure will protect the rest of the semen in the canister from thermic shock.

Motility rates are affected by canister misuse and storage tanks with low liquid nitrogen. Any increase in the storage tank temperature leads to changes in crystal formation.

Thawing protocols
The thawing protocols have an important impact on motility, morphological characteristics and viability of the sperm, so it is important to follow these protocols such as thawing temperature and duration. Alta highly recommends the thaw temperature of 98ºF - 100ºF or 37ºC - 38ºC in all our quarter cc straws for 45 seconds. This will allow quicker semen thawing with less sperm cell damage.

Conclusion
During the AI process the frozen semen is exposed to undesirable temperature changes that may cause permanent damage to the sperm cell. There is an interaction between the nitrogen level, the semen handling and the thawing protocol on the percentage of viability and fertilizing capability of the semen. So it is important that the people in charge of the AI program follow the protocols to ensure good results.  EL