Mixed Model Methodology for Farm and Ranch Beef Cattle Testing Programs

Although mixed model methods for multiple traits offer a means for efficient utilization of beef cattle performance test data, excessive computational requirements have precluded routine application. This paper describes how these procedures can be applied to weaning weight and postweaning gain records to estimate breeding values for weaning weight (direct and maternal) and yearling weight. Computational simplifications are emphasized. These include the use of an equivalent model which allows a great reduction in the number of equations that need to be solved. Advantages of these procedures for a genetic evaluation program are discussed.