Effects of selection on highly heritable traits of purebred and hybrid beef cattle
Consumers are demanding meat products that have specific characteristics, particularly in terms of meat quality. Thus, the beef industry faces the challenge of consistently producing cattle that yield meat products of desirable quality. This is a difficult goal because of the large intra- and interbreed variability among beef cattle breeds. Great variation exists between breeds for both carcass composition and meat quality traits. These differences are important genetic resources for improving production efficiency and meat quality. Because of strong genetic antagonisms (-.56) between marbling and retail product percentage, there is limited opportunity to select within breeds to achieve high levels of both these traits. Crossbreeding offers two primary advantages relative to the use of only one breed: heterosis and breed complementarity. Although research has shown little effects of heterosis on carcass and beef quality attributes, crossbreeding can still be utilized to take full advantage of the strengths of two or more breeds through breed complementarity. Because marbling and other carcass attributes are highly heritable (.30 - .50), these traits will more quickly respond to selection. Therefore, accurate identification and selection of the most elite animals within a population is essential in maximizing genetic progress. An acceptable approach for genetic improvement among antagonistic traits utilizing systematic crossbreeding is to first evaluate breed or breed type followed by within breed selection.