Table 1.
Predictive methane equations developed from measurements in respiration chambers.
| Reference | Equation | R2 | N |
|---|---|---|---|
| IPCC [98] a | Methane (kg/dag) = GE (MJ/d) × Ym/55.65 | ||
| Yan et al. [103] b | Methane (L/d) = 47.8 × DMI − 0.76 × DMI2 − 41 (kg/d) | 0.75 | 315 |
| Yan et al. [103] bc | Methane (L/d) = 0.34 × BW (kg) + 19.7 × DMI (kg/d) + 12 | 0.77 | 315 |
| Kirchgessner et al. [104] d | Methane (g/d) = 63 + 79 × CF + 10 × NFE + 26 × CP – 212 × Cfat (kg/d) | 0.69 | 24 |
| Jentsch et al. [101] de | Methane (kJ/d) = 1.62 × d_CP − 0.38 × d_Cfat + 3.78 × d_CF + 1.49 × d_NFE +1142 (g/d) | 0.90 | 337 |
| Ellis et al. [21] | Methane (MJ/d) = 0.14 × forage (%) + 8.6 | 0.56 | 89 |
| Mills et al. [105] f | Methane (MJ/d) = 0.07 × ME (MJ/d) + 8.25 | 0.55 | 159 |
| Mills et al. [105] b | Methane (MJ/d) = 0.92 × DMI (kg/d) + 5.93 | 0.60 | 159 |
| Mills et al. [105] b | Methane (MJ/d) = 10.3 × forage (%) + 0.87 × DMI (kg/d) + 1.1 | 0.61 | 159 |
| Grainger et al. [26] b | Methane (g/d) = 18.5 × DMI (kg/d) − 9.5 | 0.56 | 16 |
a GE = gross energy intake; Ym = emission factor; b DMI = dry matter intake; c BW = body weight; d CF = crude fibre; NFE = N-free extract; CP = crude protein; Cfat = crude fat; e The equation is based on digested amounts which is designated with “d”; f ME = metabolizable energy intake.