Table 3.
Effect of dietary CP level on intake and apparent total-tract digestibility.
| Dietary CP Content, g/kg DM | SEM | p-Value | ||||||
|---|---|---|---|---|---|---|---|---|
| 141 | 151 | 177 | 201 | Diet | Linear | Quadratic | ||
| DM intake, kg/day | ||||||||
| Silage | 9.1 b | 9.1 b | 10.7 a | 9.4 b | 0.359 | 0.014 | 0.138 | 0.011 |
| Concentrate | 10.1 b | 9.9 b | 11.8 a | 10.4 b | 0.383 | 0.012 | 0.147 | 0.017 |
| Total | 19.2 b | 18.9 b | 22.5 a | 19.8 b | 0.730 | 0.011 | 0.136 | 0.013 |
| OM intake, kg/day | 17.7 b | 17.4 b | 20.7 a | 18.2 b | 0.665 | 0.012 | 0.152 | 0.013 |
| CP intake, kg/day | 2.72 b | 2.86 b | 3.98 a | 3.95 a | 0.132 | <0.0001 | <0.0001 | 0.015 |
| NDF intake, kg/day | 7.91 b | 7.72 b | 8.98 a | 7.68 b | 0.309 | 0.026 | 0.700 | 0.015 |
| ADF intake, kg/day | 4.19 b | 4.12 b | 4.83 a | 4.15 b | 0.183 | 0.039 | 0.516 | 0.021 |
| Apparent total-tract digestibility | ||||||||
| DM, g/kg | 707 | 719 | 715 | 715 | 13.1 | 0.890 | 0.773 | 0732 |
| OM, g/kg | 728 | 737 | 737 | 734 | 12.6 | 0.922 | 0.778 | 0.624 |
| CP, g/kg | 571 c | 611 b,c | 641 b | 695 a | 16.8 | 0.0002 | <0.0001 | 0.928 |
| NDF, g/kg | 604 | 623 | 607 | 590 | 20.9 | 0.640 | 0.391 | 0.524 |
| ADF, g/kg | 613 | 626 | 618 | 591 | 20.6 | 0.556 | 0.289 | 0.414 |
SEM, standard error of least square means; OM, organic matter; a,b,c least square means in the same row with different superscript letters differ (p < 0.05).