Other than the few bulls needed for breeding, the vast majority of male cattle are slaughtered for meat before the age of three years, except where they are needed (castrated) as work oxen for haulage. Most of these beef animals are castrated as calves to reduce aggressive behavior and prevent unwanted mating, although some are reared as uncastrated bull beef. A bull is typically ready for slaughter one or two months sooner than a castrated male or a female, and produces proportionately more, leaner muscle.
Frame score is a useful way of describing the skeletal size of bulls and other cattle. Frame scores can be used as an aid to predict mature cattle sizes and aid in the selection of beef bulls. Frame scores are calculated from hip height and age. In sales catalogues, this measurement is frequently reported in addition to weight and other performance data such as estimated breed value (EBV).