Humans started domesticating farm livestock over 10,000 years ago. For much of this time, livestock have been changed genetically by subjective means. In the past 50 years, the application of scientific methods to animal breeding has led to major improvements in the output, cost and quality of animal products in the last few decades. This book describes the principles of genetic improvement of farm livestock and the practical application of these principles to dairy cattle, beef cattle and sheep breeding. Originally published in 1998 by Farming Press.