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Table 3 Regression equations to estimate intake, digestibility, faecal N, and liveweight
| Regression equation 1,2 | r2 | Sig. of regression | |
|---|---|---|---|
| Intake | |||
| Concentrate intake (kg DM/d) | Y = −2.39 + 0.0117(I) + 2.68(C) - 0.348(C2) | 0.97 | <0.0001 |
| Guinea grass intake (kg DM/d) | Y = 0.701 + 0.00782(I) - 0.321(C) | 0.69 | 0.0002 |
| Rice straw intake (kg DM/d) | Y = 0.747 + 0.00539(I) - 0.00808(C) - 0.209(C2) | 0.93 | <0.0001 |
| Substitution rate (kg DM/kg DM) | Y = 1.16 - 0.00589(I) + 0.215(C) | 0.85 | <0.0001 |
| 3OM intake (kg/day) | Y = −0.996 + 0.0227(I) + 2.30(C) - 0.535(C2) | 0.95 | <0.0001 |
| 4GE intake (MJ/d) | Y = −18.9 + 0.438(I) + 43.8(C) - 10.1(C2) | 0.94 | <0.0001 |
| 5CP intake (kg/d) | Y = −0.278 + 0.00307(I) + 0.407(C) - 0.0693(C2) | 0.97 | <0.0001 |
| 6EE intake (kg/d) | Y = −0.114 + 0.000818(I) + 0.144(C) - 0.0221(C2) | 0.97 | <0.0001 |
| 7NDF intake (kg/d) | Y = 1.27 + 0.00886(I) - 0.240(C) | 0.48 | 0.0036 |
| Digestibility period | |||
| OM digestibility (%) | Y = 54.4 + 8.00(C) | 0.84 | <0.0001 |
| Digestible OM intake (kg/d) | Y = −0.149 + 0.0106(I) 0.971(C) | 0.88 | <0.0001 |
| Gross energy digestibility (%) | Y = 75.0 + 13.6(C) - 4.36(C2) | 0.43 | 0.0086 |
| Digestible energy intake (MJ/d) | Y = −7.39 + 0.311(I) + 38.5(C) - 8.75(C2) | 0.89 | <0.0001 |
| CP digestibility (%) | Y = 56.9 + 6.09(C) | 0.63 | <0.0001 |
| EE digestibility (%) | Y = 9.28 + 0.0884(I) + 38.8(C) - 7.62(C2) | 0.93 | <0.0001 |
| NDF digestibility (%) | Y = 59.8 - 8.06(C) | 0.63 | <0.0001 |
| Faecal N (kg/d) | Y = −0.00168 + 0.000129(I) + 0.0203(C) - 0.00589(C2) | 0.89 | <0.0001 |
| Liveweight | |||
| Initial liveweight (kg) | n.a. | n.a. | 0.9905 |
| Final liveweight (kg) | Y = −13.7 + 1.12(I) + 64.9(C) - 15.6(C2) | 0.97 | <0.0001 |
| Liveweight gain (kg/d) | Y = −163 + 1.43(I) + 773(C) - 185(C2) | 0.90 | <0.0001 |
