NR 33. Effect of phenolic compounds release from straw by ammonia treatment on fibrolytic microbial activity

Analyses of variance of cut-out data (percentages of beef cuts, bone or trimmed fat) from 22 bulls were calculated to validate effectiveness of two grading criteria to segregate groups of carcasses with distinct commercial composition. Bull carcasses graded A (n=7) or C (n=15) by the official carcass grade (OCG) and 2 (n=10), 3 (n=6) or 4 (n=5) by the Yield Index (IRC). Only three individual cuts out of the 19 individual carcass components under study were significantly affected by the OCG, whereas none of the components (P>0.05) was affected by IRC. Moreover, OCG affected (PB), boneless chuck (A>B), MIDVALUE (A>B) and LOWVALUE (B>A). However, given the disparity of these results with other companion trials, it was concluded that revision of the present grading system should consider the use of a more reliable method for the prediction of commercial value of beef carcasses.