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OBJECTIVE: The objective of this study was to compare carcass grading outcomes of progeny from a sire derived via carcass cloning to progeny from a competitive traditional purebred Angus sire. Semen was artificially inseminated into Jersey cows from an F1 sire (AxG1) derived from Prime-yield grade 1 carcass clones and a highperformance purebred Angus sire (Foundation). Calves were born at the dairy, raised in hutches on the dairy, and grown in a separate facility, all in the Texas panhandle. Cattle were later transported to Nebraska for finishing. Both steers and heifers were harvested at a commercial beef processor in Colorado and camera data were collected to assess carcass quality and yield outcomes. Data were analyzed using mixed models; treatment comparisons were tested for significance with a = 0.05. RESULTS: In live growth, calves sired by Foundation were heavier (P < 0.01) both when they entered (396.1 vs 383.0 kg) and exited (590.1 vs 568.8 kg) the feedyard. Similarly, calves sired by Foundation had heavier (P < 0.01) hot carcass weights than AxG1 (374.9 vs 361.4 kg). No difference (P = 0.27) was detected between sires for longissimus muscle area (96.6 vs 95.7 cm2) or marbling score (Moderate26 vs Moderate20). AxG1 sired calves had greater (P < 0.01) muscle area per unit of carcass weight (26.7 vs 25.9 cm2/100kg). Calves sired by AxG1 were leaner (P < 0.01) than those sired by Foundation as evidenced by less 12th rib s.c. fat (1.11 vs 1.26 cm) coupled with decreased calculated yield grades (2.34 vs 2.59). Moreover, calculated Empty Body Fat was greater (P < 0.01) for Foundation sired carcasses than those sired by AxG1 (30.0 vs 28.9 %). Foundation sired calves were represented by a greater (P < 0.05) percentage of USDA Prime carcasses (26.32 vs 17.79 %) whereas AxG1 sired calves had a greater (P < 0.05) percentage of USDA Choice carcasses (77.74 vs 69.48 %). AxG1 sired calves were represented by a greater (P = 0.04) percentage of Yield Grade 1 carcasses (27.48 vs 19.25 %). No difference in frequency of Yield Grade 2 (55.40 vs 58.00 %) or 4 (1.41 vs 1.0 %) carcasses was observed between sires. Frequency of Yield Grade 3 carcasses was greater (P < 0.01) for Foundation compared with AxG1 (23.94 vs 13.58 %). Carcass outcomes suggest that progeny sired by Foundation were of slightly higher quality whereas progeny sired by AxG1 were of slightly higher yield. [ABSTRACT FROM AUTHOR]

The association of lung abnormalities with carcass performance was evaluated on data from 60,843 carcasses housed in the West Texas A&M University Beef Carcass Research Center database collected from 2010 to 2021 to quantify the relationship of lung health and carcass performance. Lung outcomes were scored as severity of consolidation (N = Normal and free of consolidation, 1 = 5 to 15% consolidation, 2 = 15 to 50% consolidation, 3 = >50% consolidation) and presence of fibrin tags (M = Minor fibrin, E = Extensive fibrin). Lung consolidation had a strong and detrimental effect (P < 0.01) on hot carcass weight, with lung scores of 1, 2, and 3 resulting in 4.2, 13.3, and 29.9 kg less carcass weight compared with carcasses with normal lungs. Minor and extensive fibrin tags (3.5 kg and 7.1 kg), independent of consolidation, resulted in lighter carcasses (P < 0.01) compared with those with normal lungs. Lung score did not have an effect on marbling score. Both lung tissue consolidation and fibrin tags effected 12th rib fat thickness; lung consolidation (-0.09 to -0.21 cm) and fibrin tags (-0.14 to -0.19 cm) resulted in and less (P < 0.01) 12th rib fat thickness compared with carcasses with normal lungs. Similarly, LM area was reduced (P < 0.01) in carcasses with lung consolidation (-1.5 to -5.5 cm2) or presence of fibrin tags (-2.3 to -2.7 cm2) compared with carcasses with normal lungs. Additionally, severity of lung consolidation and presence of fibrin tags reduced (P < 0.01) calculated yield grade; lung consolidation and fibrin tags resulted in a 0.08 to 0.20 and 0.09 to 0.13 reduction in overall yield grade. These data indicate that lung health is an important factor that impacts carcass performance, particularly carcass weight and yield grade parameters. [ABSTRACT FROM AUTHOR]

Heifers (n = 1,394; 291 ± 9.9 kg) were used to test the effects of a direct-fed microbial (10-G) on live growth performance and carcass characteristics. Heifers were blocked by arrival day and randomly allocated to treatment (0 or 2g/animal/d; CON and 10-G, respectively) in a randomized complete block design with ten pens per treatment. Heifers were fed for an average of 192 days. Growth and carcass outcomes were analyzed using mixed models with pen as experimental unit and block as random effect. Dry matter intake (P = 0.63), average daily gain (P = 0.69), gain:feed (P = 0.95) and final body weight (P = 0.79) did not differ between treatments. Neither deads and removals (P = 0.52) nor first or second treatment morbidity rates (P = 0.84) were different between treatments. Hot carcass weight (P = 0.19), dressed carcass yield (P = 0.33), 12th rib fat depth (P = 0.73), ribeye area (P = 0.13), calculated empty body fat (P = 0.71) or marbling score (P = 0.20) were not different between treatments. Yield grade distributions did not differ between treatments (P = 0.44), however cattle fed 10-G tended (P = 0.09; 15.78 vs 20.34%) to be represented by fewer USDA Select carcasses. Livers from cattle fed 10-G tended (P = 0.10; 1.02 vs 2.19%) to have a lower frequency of abscesses when compared to CON. Heifers fed 10-G also had fewer (P < 0.05; 5.27 vs 8.51%) severe liver abscesses. These results suggest that supplementing fed beef heifers with 10-G decreased rates of severe liver abscesses without altering live animal performance or carcass characteristics. [ABSTRACT FROM AUTHOR]