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Abstract
The objective of this study is to compare growth performance, feed efficiency, body composition, and carcass characteristics in steers, and to compare growth, body composition, and reproductive performance in heifers from bulls divergently selected for feed efficiency. Angus sires were selected with high and low residual average daily gain (RADG) EPDs and high and average marbling (MARB) EPDs. This resulted in a 2x2 factorial arrangement with four treatment combinations: high RADG, high MARB (Hi/Hi); high RADG, average MARB (Hi/Avg); low RADG, high MARB (Lo/Hi); and low RADG, average MARB (Lo/Avg). The overall goal of this research program is to develop lines of cattle using RADG EPD so that a better understanding of the biological and physiological basis of efficiency in beef cattle can be ascertained. Selection using RADG EPD resulted in improved feed efficiency in steer progeny; however additional research is needed in heifer progeny.