Relationship between Slaughter and Carcass Grades in Beef Cattle2

Members of the Department of Animal Husbandry at Kansas State University independently graded 688 Hereford heifers and steers to the nearest one-third of a grade just before they were slaughtered. Each carcass was graded to the nearest one-third of a grade by an official of the U.S.D.A. Federal Grading Service. Eighty-one percent of the carcass grades after ribbing ranged from average good to average choice. Weighted average correlations between slaughter grade and carcass conformation ranged from .23 to .56. All were statistically highly significant except the .23, which was significant. All average correlations (which ranged from .28 to .55) between slaughter grade and carcass grade before ribbing were highly significant. Average correlations between slaughter grade and carcass grade after ribbing ranged from .07 to .39. All but two were highly significant and only .07 was nonsignificant. Repeatability of slaughter grade was .50. Weighted average correlations between carcass conformation and carcass grade before ribbing, after ribbing, and degree of marbling were .42, .25, and .25, respectively. Correlations between carcass grade before ribbing and after ribbing averaged .53. Those between carcass grade before ribbing and degree of marbling averaged .45. Average correlation between carcass grade after ribbing and degree of marbling was .89.