Cold shock causes loss of motility, sperm metabolic activity and fertilizing ability of sperm.
Cold shock occurs when semen is thawed and then subjected to cool or cold environmental temperatures before reaching the cow. The severity of damage depends on rate and duration of temperature drop. Touch the rod to your cheek to determine if it is warm enough. It should be roughly body temperature. The period of time between straw removal from liquid nitrogen and semen deposition in the cow should be as short as possible, but do not rush because that is when mistakes are usually made.