A semen tank is a stainless steel container that is used to store semen that will eventually be used for artificial insemination of women or other methods of inducing pregnancy. Filled with liquid nitrogen, the semen tank is capable of storing large quantities of semen for long periods. Commonly used for storing frozen semen, the semen tank can be filled with fresh semen that has been placed inside of storage vessels called straws. The straws containing the fresh, live semen are then placed into the tank where the liquid nitrogen freezes the semen almost instantly, keeping it viable until it is ready to be used.
Fertilization of an egg is not the only reason that semen might be stored in a semen tank. Doctors have several reasons for maintaining semen in a semen tank, with research and testing being the primary reasons that such action is taken. By preserving the semen in a cryogenically-safe container, doctors are able to test small samples of semen several times by using only the amount of semen required for the actual test. The remaining semen can be placed back into the semen tank until it is needed once again.
Other uses for the tank are found in transporting semen samples to various laboratories. Small versions of the tank are commonly used to package samples of semen as they are being mailed to outside laboratories. In some cases, a doctor is able to package a semen sample in a liquid nitrogen-filled tank and ship it through a mail system or an overnight delivery services to a better-equipped lab so that it can be more accurately tested. This can also be the case for court-ordered samples to prove or dismiss parental issues, questions of ethnicity and relation, as well as to provide evidence in any matter of trial issues.
Used daily in the dairy and cattle industry, the semen tank is used to store up to 500 straws of bull semen that is used to artificially inseminate a cow. This is done to provide herdsmen all around the globe with the capabilities of breeding to a special bull in the hopes of improving the milk production, calf quality or even using the offspring of the frozen bull semen for future breeding. Breeders of champion bucking bulls also market the semen of the champion to breeders in the hopes of replicating the same qualities of the champion in a new bloodline.