Semen collection and artificial insemination play important roles in the genetic improvement of livestock species. The frozen semen technology damages the sperm during the process of cryopreservation and thawing of the semen. Therefore additives are included in the semen extender to prevent the cryodamage during the process of cryopreservation. The common additives are bovine serum albumin, catalase, glutathione, cysteine hydrochloride, taurine, trehalose, superoxide dismutase and so as to improve the semen quality parameters. This book will be useful to the scientists working in the andrology or semen processing laboratory, animal breeders, dairy farmers or commercial frozen semen banks and extender/preservatives manufacturing companies.