Better validation of indigenous domestic animal genetic resources is becoming more important with regard to the potential of livestock for poverty alleviation and income generation. To improve indigenous breeds for sustainable income and employment generation, the methods to be employed are the same as developed in systematic breeding programs, be it for cross-breeding or selective breeding within a specific breed. This book systematically introduces the reader to the breed improvement theory and illustrates the theory with practical examples and case studies. The book is addressed to animal science teachers, to undergraduate and postgraduate students as well as to decision makers in the state and central livestock departments.