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Palatability of steaks from young bulls that had or had not been electrically stimulated (ES) and steers that had not been electrically stimulated (non-ES) were compared. Steaks from non-ES young bulls, as compared with steaks from matched (for marbling and skeletal maturity) steers, had lower (P<.05) tenderness and connective tissue ratings and higher (P<.05) shear force values. Steaks from U.S. Choice steers and from U.S. Good steers or bulls that had at least 7.6 mm fat thickness did not differ (P>.05) in 28 of 30 possible comparisons of palatability characteristics. Steaks from U.S. Standard bulls and steers and U.S. Good bulls and steers that had less than 7.6 mm fat thickness were less palatable than steaks from U.S. Choice steers or from U.S. Good bulls and steers that had at least 7.6 mm fat thickness. These data indicate that the USDA might well give further consideration to a revision of its beef grade standards that would permit “A” maturity carcasses with a “slight amount” of marbling and at least 7.6 mm fat thickness to grade U.S. Choice, irrespective of their sex class.

Effects of electrical stimulation (ES), subcutaneous fat thickness and carcass masculinity on quality-indicating characteristics and palatability of beef from young bulls were evaluated. Electrical stimulation improved lean maturity (P<.0001) and overall maturity (P<.0001) scores, increased muscle fiber tenderness (P<.009) and overall tenderness (P<.005) ratings, and decreased the variation in palatability of steaks from young bull carcasses. Steaks from unstimulated (non-ES) young bulls with less than 6.5 mm fat thickness as well as steaks from “very masculine” carcasses were not as palatable as steaks from fatter, or less “masculine”, non-ES bull carcasses. Electrical stimulation had the greatest effect on the tenderness of steaks from young bulls with less than 6.5 mm fat thickness or “very masculine” bulls and essentially eliminated differences in tenderness of steaks from young bulls that differed in fat thickness or overall masculinity. Steaks from non-ES bulls in different overall masculinity groups did not differ (P>.05) in overall tenderness when fat thickness was held constant; therefore, for steaks from non-ES bulls, it seems that subcutaneous fat thickness is more important than masculinity as a predictor of differences in palatability.

Two-hundred and eighty beef carcasses were used to provide information on retail cut yields from beef carcasses varying widely in weight, fatness and muscling. In multiple regression equations, actual carcass measurements and commonly used subjective carcass evaluations usually accounted for over 80% of the variation of these yields. Adjusted fat thickness over the ribeye, percentage of kidney, pelvic and heart fat, and ribeye area, in that order, were the most important factors for predicting carcass yields of boneless, closely trimmed retail cuts. Carcass weight also contributed significantly (P<.05) in the equations in which it was used. These are the same four factors presently used in the official yield grade standards. On the average, the carcasses had higher yields than were predicted by the yield grades. A regression equation developed from this study and based on the same factors was only slightly more highly correlated with cutability than was the equation from which the present yield grades were derived. There also was little evidence that the equation from which the present yield grade equation was derived discriminated against certain types of carcasses more than the corresponding equation developed from this study. Therefore, there would be little advantage to revising the present USDA yield grade standards for the purpose of improving the cutability predictions of the present standards.

Feeder steers (n=471) were fed for 100, 130 or 160 days, then slaughtered, and carcass grade data were collected. A wholesale rib was removed from each carcass, vacuum packaged, and aged for 12 to 14 days, and steaks were obtained, Palatability of the steaks generally increased as marbling score increased; however, the differences in palatability associated with each successive increase in marbling score were not always directionally consistent, nor were they always statistically significant. Steaks from the highest grading (by thirds of grades) carcasses (high Choice and average Choice) were (P<.05) more juicy, more flavorful and more desirable in overall palatability than were steaks from the lowest grading (by thirds of grades) carcasses (low Good and high Standard); however, steaks from low Choice, high Good and average Good carcasses did not differ in ratings for juiciness, tenderness or overall palatability. When steaks from carcasses of different grades (by full grades) were compared, grade was not associated with differences in palatability. Increased time on feed was associated with increased carcass maturity, increased fat deposition, decreased (higher numerical) yield grade and increased percentage of carcasses grading Choice. Increased feeding time from 100 days to 160 days had a beneficial effect on flavor desirability but did not significantly affect juiciness, tenderness or overall palatability. These data suggest that knowledge of feeding history might be a useful adjunct to — or substitute for — USDA quality grade for predicting beef palatability.