Over the last few years, effect of various additives was studied to improve the quality of semen in cattle. These additives include antioxidants, sugars, cholesterol and proteins, etc. Out of which, few are effective and improved the semen quality even in post thaw stage. These additives improve both in vitro and in vivo fertility in all species of animals. Study of these additives will improve the conception rate and reduces the repeat breeding due to poor quality semen. This book will help to the breeders and farmers to improve the fertility in artificial breeding centres and enhance reproductive performance in cost effective manner.