Artificial insemination is a technique in genetic improvement in the livestock industries. Frozen semen technology enhances the efficacy of the artificial insemination. Semen freezing technology damages the sperm structure and function during the different process of cryopreservation. These cryodamage can be reduced with use of different cryo-protectors as additives or antioxidants in frozen semen extenders which can improve the freezability of the sperm to enhance the fertility rate. Some of additives are catalase, glutathione, cysteine hydrochloride, taurine, trehalose, superoxide dismutase, etc are also included in the semen extender to protect the sperm from oxidative cryodamage. 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.