Table 9.
Carcass characteristics in feedlot animals fed high-grain diet supplemented with no additives (CON), monensin (MON, 33 mg/kg DM), 3-nitrooxypropanol (NOP, 125 mg/kg DM), and combination of MON and NOP
| −MON | +MON | P value | ||||||
|---|---|---|---|---|---|---|---|---|
| Variable | −NOP | +NOP | −NOP | +NOP | SEM1 | MON | NOP | MON × NOP |
| No. of steers (pens) | 60 (8) | 60 (8) | 60 (8) | 60 (8) | — | — | — | — |
| BW, kg | 730 | 734 | 732 | 735 | 11.2 | 0.85 | 0.73 | 0.97 |
| Hot carcass weight, kg | 426 | 432 | 434 | 432 | 6.91 | 0.49 | 0.73 | 0.52 |
| Fat cover (1 mm) | 22.2 | 21.5 | 22.6 | 23.7 | 0.90 | 0.14 | 0.82 | 0.32 |
| Fat cover (2 mm) | 22.2 | 21.0 | 21.9 | 22.8 | 0.87 | 0.36 | 0.90 | 0.22 |
| Grade fat1 | 19.9 | 18.6 | 19.7 | 20.6 | 0.86 | 0.28 | 0.89 | 0.19 |
| Rib eye area, cm | 89.0 | 93.1 | 93.0 | 94.0 | 1.57 | 0.11 | 0.10 | 0.30 |
| Marbling quality | 2.90 | 2.93 | 2.90 | 2.87 | 0.070 | 0.60 | 0.99 | 0.57 |
| Marbling level | 29.4 | 27.5 | 23.9 | 28.0 | 3.58 | 0.45 | 0.73 | 0.37 |
| Saleable meat, % | 49.4 | 50.8 | 50.0 | 49.5 | 0.72 | 0.64 | 0.52 | 0.18 |
| Liver score2 | 1.70 | 1.58 | 1.57 | 1.74 | 0.140 | 0.95 | 0.89 | 0.44 |
| Dressing percentage3 | 58.3 | 58.8 | 59.3 | 58.8 | 0.44 | 0.28 | 0.95 | 0.26 |
1Grade fat is minimum backfat thickness in the third quarter between the 12th- and 13th-rib interface (Rodas-González et al., 2013).
20 = no abscesses; 1 = small abscesses; 2 = moderate abscesses; 3 = severe abscesses; 4 = adhered (Bauer et al., 2007).
3Dressing percentages were calculated individually as hot carcass weight divided by final BW × 100%.