Straws are racked vertically and
frozen in liquid nitrogen vapour at –120 to 130ºC with the
bottom and 0.5 cm above the liquid nitrogen level for 18
min. Straws are transferred into a container with liquid
nitrogen at –196ºC after which the motility of primary
freezing is checked and recovery rate assessed.
Packaging.Semen is packaged in 3 ways viz: