Multibreed Genetic Evaluations of Beef Cattle

INTRODUCTION Interest in crossbreeding in commercial cattle herds in the latter half of the 20 century sparked a flurry of experiments characterizing breeds and breed crosses for additive and nonadditive gene effects. Analytical models for estimation of these effects naturally followed. A logical extension was to apply the methodology to estimation of genetic merit from records in populations representing multiple breeds, and this area of research has received increased interest as composite and other crossbred animals are finding their way into commercial herds as seedstock. This presentation will be a discussion of the models for multiple breed genetic evaluations and on experiences gained in the application of these models to beef cattle evaluations in the U.S. It will conclude with a description of the plan for expanding multiple breed evaluations being proposed by the National Beef Cattle Evaluation Consortium (NBCEC).