In a conventional sense, dried-spermatozoa are all dead and motionless due to the lost of their natural ability to penetrate oocytes both in vivo and in vitro. However, their nuclei are completely able to contribute to normal embryonic development even after long-term preservation in a dried state when the dried-spermatozoa are microinjected into the oocytes. In this sense, dried spermatozoa must still be alive. Thus, defining spermatozoa as alive or dead seems rather arbitrary. Several drying method of sperm including freeze-drying, evaporative/convective-drying and heat-drying were represented in this review. Although the drying protocol reported here will need further improvement, the results suggest that it may be possible to store the male genetic resources.

• Duk-Im Kim(Hanwoo Genetic Improvement Center, National Agricultural Cooperative Federation)
• Chang Jin Kim(Dept. of Biology Education, College of Education, Chonnam National University)
• Kyung-Bon Lee(Dept. of Biology Education, College of Education, Chonnam National University) Corresponding author