RELATIONSHIP BETWEEN USDA AND JAPANESE BEEF GRADES

Angus steers (n = 75) were feedlot-finished to approximately 703 kg live weight. The finished steers were slaughtered at a commercial packing plant, chilled, and evaluated for USDA and Japanese yield and quality-grade characteristics. The resulting carcasses were excessively heavy and fat for the domestic (US) beef industry. Over 70% of the carcasses were US Yield Grade 5, and almost 40% were Japanese Yield Score 'C'. Although excessively fat externally, fewer than 50% of the carcasses qualified for US Prime, and none of the carcasses qualified for Japanese Meat Quality Score 5. Moderate to high correlations were observed between US twelfth-rib carcass traits and Japanese sixth-rib traits; however, multiple-regression equations based on USDA carcass characteristics explained only 46 and 25% of the observed variation in Japanese marbling score and estimated percentage wholesale-cut yield, respectively.