Table 7.
Rumen fermentation characteristics from feedlot animals fed high-forage diets supplemented with no additives (CON), monensin (MON, 33 mg/kg DM), 3-nitrooxypropanol (NOP, 200 mg/kg DM), and combination of MON and NOP
| −MON | +MON | Effect, P value | ||||||
|---|---|---|---|---|---|---|---|---|
| Variable | −NOP | +NOP | −NOP | +NOP | SEM | MON | NOP | MON × NOP |
| No. of steers | 8 | 8 | 8 | 8 | — | — | — | — |
| Total VFA, mM | 93.1a | 74.5c | 84.9ab | 80.6bc | 2.90 | 0.69 | <0.01 | 0.04 |
| Individual VFA, mol/100 mol | ||||||||
| Acetate (A) | 62.8 | 56.9 | 62.3 | 56.0 | 0.550 | 0.23 | <0.01 | 0.68 |
| Propionate (P) | 18.1 | 20.9 | 20.2 | 23.5 | 0.57 | <0.01 | <0.01 | 0.57 |
| Isobutyrate | 1.16 | 1.25 | 1.15 | 1.30 | 0.060 | 0.71 | 0.12 | 0.64 |
| Butyrate | 13.1 | 15.1 | 12.0 | 13.4 | 0.53 | 0.04 | 0.02 | 0.50 |
| Valerate | 1.80 | 1.89 | 1.58 | 1.66 | 0.060 | 0.02 | 0.22 | 0.99 |
| Isovalerate | 1.98 | 2.97 | 2.06 | 3.40 | 0.170 | 0.16 | <0.01 | 0.31 |
| Caproate | 0.97 | 0.88 | 0.66 | 0.63 | 0.060 | <0.01 | 0.28 | 0.56 |
| A:P ratio | 3.48 | 2.80 | 3.15 | 2.43 | 0.060 | <0.01 | <0.01 | 0.70 |
| NH3-N, mM | 6.98 | 4.88 | 5.52 | 4.12 | 0.380 | 0.04 | 0.01 | 0.37 |
a,bValues in a row not bearing a common letter differ (P ≤ 0.05).