Table 3.
Effect of physical form and urea treatment of rice straw on rumen fermentation and BUN in dairy steers
| Item | RS
|
UTRS
|
SEM | Significance1
|
||||
|---|---|---|---|---|---|---|---|---|
| LFR | CHR | LFR | CHR | U | P | U×P | ||
| pH | 6.3 | 6.6 | 6.4 | 6.2 | 0.02 | * | ns | * |
| NH3-N (mg/dL) | 14.1 | 12.4 | 19.6 | 22.8 | 1.50 | ** | ns | ns |
| BUN (mg/dL) | 3.2 | 4.6 | 12.5 | 12.4 | 0.57 | ** | ns | ns |
| Total VFA (mM) | 113.1 | 107.4 | 122.8 | 127.1 | 2.15 | * | ns | ns |
| VFA, mol/100 mol | ||||||||
| Acetic acid (C2) | 71.3 | 69.8 | 70.0 | 70.5 | 0.47 | ns | ns | ns |
| Propionic acid (C3) | 20.1 | 20.3 | 21.5 | 21.4 | 0.15 | * | ns | ns |
| Butyric acid (C4) | 8.5 | 10.0 | 8.4 | 8.2 | 0.73 | ns | ns | ns |
| C2:C3 | 3.7 | 3.5 | 3.3 | 3.4 | 0.15 | ns | ns | ns |
1
U = Untreated rice straw vs urea-treated (3%) rice straw, P = Long form rice straw vs chopped (4 cm) rice straw, U×P roughage source and physical form interaction.
*
p<0.05,
**
p<0.01, ns = Non-significant (p>0.05).