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The study which provided the basis for the development of the standards for yield grades of beef carcasses was reported by Murphey et al.(1960). The equation which was used as a basis for the yield grade standards was adpated from the regression equation, percent boneless retail cuts from round, loin, rib and chuck=51.34 −5.78 (single fat thickness over ribeye, in.) −.462 (percent kidney fat) + .740 area of ribeye, sq. in.) −.0093 (carcass wt., lb.). This equation was developed from data taken from 162 carcasses covering the full range of the quality grades (Prime to Canner) and included steers, heifers and cows. “When the U.S.D.A. equation is applied to another population of more homogeneous carcasses, one should not expect necessarily to obtain the exact relationship between estimated yield of retail cuts and actual yield of retail cuts as observed in the original U.S.D.A. study,” (Stringer et al., 1968).The objective of this study was to determine the predictive values of five carcass measurements when weight and percent retail cuts were predicted, using measurements taken from steer carcasses with a narrow range of quality grades and carcass weights.

Forty-eight average Choice and 36 average Good conformation steer carcasses were used to study the effect of carcass conformation, hot carcass weight and fat thickness at the 12th rib on yield of uniformly trimmed retail cuts.Average Choice conformation carcasses yielded a higher percent (P<.05) of total retail cuts than average Good conformation carcasses mainly due to a higher yield of minor retail cuts and less bone. There were no significant differences in percent of retail cuts from the primal wholesale cuts or percent of thick retail cuts (roasts and steaks) attributable to conformation.Hot carcass weight did not significantly affect the percent of retail cuts when conformation and fat thickness were similar.Fat thickness at the 12th rib (1.31 to 2.0 vs.0.8 to 1.3 cm.) had a more consistent effect on weight and percent retail cuts than conformation or carcass weight. Carcasses with greater fat thickness yielded less retail cuts and more fat than carcasses with less fat thickness.

Two hundred steers, progeny of 12 pure-bred beef sires, were allotted equally by sire group into five lots after being weaned and were full-fed a growing and finishing ration for 139 to 251 days. A lot of cattle was slaughtered every 28 days during this period. The right side of each carcass was processed into retail cuts.Slaughter weight and carcass weight increased as the length of time on feed increased. A slight over-all decrease in rate of gain and an over-all increase in dressing percent were associated with extended time on feed. Mean carcass quality grade by lot did not improve significantly after 195 days on feed.Significant differences in quantitative and qualitative carcass characteristics existed among progeny of the various sires. Some sire differences in percent retail yield were affected by days on feed.The most significant effect of extended feeding from 139 to 251 days was an increase in percent fat and a decrease in percent retail cuts.Steers full-fed on a finishing ration beyond average to high Good had a disadvantage in total percent retail cuts and in the percent of retail cuts from the high priced primal cuts. Percent retail cuts from progeny of most sires decreased as days on full feed increased.

Short loin steaks from 200 beef steers were evaluated to determine the effects of sire, length of feeding, and sire x length of feeding upon flavor, tenderness, and over-all desirability. The steers were the progeny of 12 beef sires, neither the steers or the sires being a random sample of the population. Lot 1 was fed 139 days and thereafter, a lot was taken off feed every 28 days; for example, lot 5 was on feed 251 days.Laboratory flavor intensity scores were affected by length of time on feed (P<.01) and by sire (P<.05). Significant (P<.01) differences in flavor desirability scores due to length of feeding and sire were observed by the laboratory panel but not by the consumer panel. Tenderness desirability scores were significantly (P<.01) affected by sire, length of time on feed, and by sire x length of time on feed in the laboratory panel. The consumer panel did not detect any significant differences in tenderness desirability (P<.05). Mean Warner-Bratzler shear values were significantly (P<.05) affected by sire and length on feed. Over-all desirability scores were significantly (P<.01) affected by sire, length of time on feed and by sire x length of time on feed in the laboratory panel. The consumer panel did not detect any significant differences in over-all desirability of the steaks.Under the conditions of this study, feeding beyond 139 days (lot 1) did not result in consistent increases or decreases in flavor intensity, flavor desirability, tenderness desirability or over-all desirability. Sire and sire length of time on feed effects upon palatability appear to be worthy of further consideration.

Thirty-one choice grade beef short loins were used to determine the effect of cooking method (broiling and cooking in deep fat), sample core size (1.27 cm. and 2.54 cm.), temperature of sample when sheared (hot and cold), and sample core position (medial, central and lateral) on Warner-Bratzler shear values. Shear values were significantly affected by all treatments. Sample cores from steaks cooked in deep fat had higher shear values than samples from broiled steaks. Sample cores sheared cold had higher shear values than sample cores sheared hot. Sample cores from the central and lateral locations had higher shear values than sample cores from the medial location. Low but significant positive relationships were observed between shear values for the various treatments employed.