The goal of most beef production systems is to increase or at least maintain profitability. Producers can attempt to increase profitability in a variety of ways that might include reducing feed costs, changing their marketing program, or perhaps by changing the performance of their herd through genetic improvement. Focusing on this latter option, there are two primary genetic tools available: selection and mating where selection refers to the selection of breeding animals and mating includes which females are mated to which bulls, for example, crossbreeding systems. This paper focuses on the former, the selection of the appropriate animals for a production system with the goal to improve profitability. The best tool available for making se...