To appear in Genetics of Cattle 2nd Edition, Garrick D.J, Ruvinsky A (Editors), CAB International Genetic Improvement of Dairy Cattle

As for any species or population, genetic improvement of dairy cattle involves determining a desirable direction for improvement, identifying traits that provide information to move in that direction, quantifying their heritability, deciding how to evaluate them, and designing a breeding program to achieve the goals. With regard to these issues, dairy cattle are one of the most highly studied of all domesticated species. This chapter describes how to determine which goals should be established to emphasize profit or efficiency as the ultimate goal of the dairy enterprise. The traits typically measured are listed along with how they are related and the genetic parameters utilized in the selection process. Evaluation procedures used to establish genetic rankings based on observations on related animals (genetic evaluations) or on genomic information (genomic evaluations) are reviewed. Their incorporation into breeding programs is outlined.