The Genetic Basis For Increased Productivity

The Genetic Basis For Increased Productivity Considerable research by various State Agricultural Experiment Stations and the USDA has clearly demonstrated the potential for increasing beef cattle productivity through crossbreeding. Consequently, the use of crossbreeding for the commercial production of beef is rapidly increasing. Crossbreeding (the mating of animals from different breeds) is similar in principle to a widely used mating system in straightbreeding programs known as outcrossing (the mating of unrelated and therefore genetically unlike animals within the same breed). Traditionally, breeders have used outcrossing to increase performance levels within a breed by mating animals from distinctly different families or bloodlines. The results from crossbreeding are generally of larger magnitude than outcrossing, since, on the average, animals from different breeds will be more genetically dissimilar than animals from different families within the same breed. The genetic aspects of crossbreeding and outbreeding are similar, however. There are two ways that crossbreeding can result in increased production levels. Crossbreeding provides the breeder the opportunity of combining the desirable characteristics of two or more breeds, thus achieving a higher overall performance level of desired traits among the crossbred animals than would generally be found within a given breed. This is frequently called breed complementarity, which refers to the strong points of one breed complementing or covering up the weak points of the other breed. The second way crossbreeding increases productivity is through the increased levels of performance for particular traits due to heterosis. Increased productivity can result through heterosis exhibited by both the crossbred calf and the crossbred cow.