The Effect of Market Weight and Ration Concentrate Level on Carcass Traits of Bulls, Heifers and Steers

Increasing worldwide demand for animal protein, growing pressure on the available cereal grains by a multiplying world population and greater availability of United States agricultural products worldwide make it imperative that beef volume and production efficiency increase. Consumer demand for a lean, high quality, trim product dictates production of rapid growing, efficient beef animals with minimum fat deposition at market weights. In the face of increasing demand, governmental constraints in the form of economic controls, ecological considerations and restrictions in the use of antibiotics and growth promoting agents force the beef industry to examine and improve production efficiency. Currently, packers place a premium on high yielding cattle in the choice quality grade. Most packer costs are on a per head basis and thus they are concerned with maximizing total carcass weight processed through their plants. Feeding costs, however, soar as cattle are fed to heavier weights. Most feedlot cattle are fed high concentrate diets during this "fattening" period as a greater percentage of energy intake is producing fat. Cattle on a low concentrate ration are less efficient as less energy is left for production after maintenance requirement is met, and a longer feeding period is required. Increasing competition for feed grains by an expanding human population and a growing demand for a trim, lean product makes it important to find management systems which will optimize beef production. Economic changes in the inputs required for beef production may force management changes. Optimization of ration energy content and final slaughter weight offer possibilities for increasing beef production efficiency. The purposes of this study were to evaluate (1) the effect of a light or heavy market weight on carcass composition, (2) the effect of ration concentrate level on quantitative and qualitative carcass traits and (3) the influence of ration concentrate level on carcass composition in different sex groups of Hereford cattle.