Since animals were first domesticated, animal breeders have been using selective breeding to determine which animals will become parents of the next generation. Initially, this decision was based on the animals’ appearances. For example, when domesticating the wolf to generate the different dog breeds, parents were selected based on temperament. Different temperaments are helpful for herding dogs vs. guard dogs. Appearance is another important trait because some dogs are large and some are small. As scientific understanding of genetics improved, it became clear that animals inherit traits from their parents. Traits are passed on through genes, which are small bits of information in your cells. This book contains a comprehensive study of the biology and genetics involved in all aspects of stock breeding. Of the several sciences which may serve the breeder, genetics is the one which bears upon his breeding practices. It is the science which seeks to account for the similarities and dissimilarities in characterisation exhibited by individuals related by a common ancestry and to define the exact relation between successive generations. This book is very much useful for the graduate students studying in veterinary colleges all over India.