Effects of Wagyu Breeding and Finishing Environment on the Performance and Carcass Merit of Single-Calving Heifers¹

Three trials were conducted to determine the effects of the changed USDA quality grade guidelines and finishing environment on the performance and carcass merit of Angus-sired and Wagyu-sired single-calving heifers. In trial 1, nine Angus and 15 Wagyu single-calving heifers were finished to a compositional subcutaneous fat cover of 1.0 cm on a corn/corn silage-based diet. Feedlot performance was not affected by sire breed. Wagyu (59.4 ± 0.49%) heifers had a higher (P<0.05) dressing percentage than Angus (57.3 ± 0.67%) heifers. Differences in dressing percentage between Angus and Wagyu heifers were likely the reflection of numerically thicker subcutaneous fat cover carried by Wagyu heifers. Eighty-eight percent of the single-calving heifers graded USDA choice under the 1989 USDA quality grade guidelines, while only 70% graded choice under the 1996 USDA quality grade guidelines. Quality grade did not differ (P<0.10) between breeds. In trial 2, seven Wagyu and eight Angus singlecalving heifers were individually fed to a compositional subcutaneous fat cover of 1.4 cm. No differences in feedlot performance resulted from sire breed. Angus heifers tended (P<0.09) to have a higher yield grade than the Wagyu heifers. All heifers graded USDA choice under the 1996 quality grade guidelines. In trial 3, 27 Wagyu single-calving heifers were finished in a pasture or a feedlot environment. Pasture-fed heifers consumed less (P<0.05) concentrate than the feedlot-finished heifers. Average daily gains and efficiency of gain were numerically (P>0.10) lower as a result. Carcass merit was not significantly affected by finishing environment. The single-calving heifer system was a viable option for beef production despite the changes in USDA quality grade guidelines.