Table 4.
Equations using dietary CP as independent variable
| Dependent variables | Equation | AIC | MSE | R2 | P-valued |
|---|---|---|---|---|---|
| VFA, %, otherwise stateda | |||||
| Total VFA, mM | Ŷ = 29.2671 + 7.9317 × CP – 0.2264 × CP2 | 3,485 | 135.1 | 0.13 | 0.01 |
| Acetate | Ŷ = 54.56 | 2,882 | 28.4 | — | >0.05 |
| Propionate | Ŷ = 25.723 + 0.3937 × CP – 0.02629 × CP2 | 3,014 | 26.3 | 0.64 | 0.04 |
| Butyrate | Ŷ = 13.16 | 2,636 | 11.0 | — | >0.05 |
| True digestibility, % | |||||
| OM | Ŷ = 55.89 | 2,966 | 29.2 | — | >0.05 |
| CP | Ŷ = 57.69 | 2,395 | 44.3 | — | >0.05 |
| NDF digestibility | Ŷ = 45.45 | 2,767 | 62.0 | — | >0.05 |
| NH3–N, mg/dL | Ŷ = 4.2717 × exp(0.0647 × CP) | 1,045 | 11.0 | 0.16 | 0.01 |
| N flow, g/d | |||||
| NH3–N | Ŷ = 0.09499 × exp(0.07532 × CP) | 185 | 0.03 | 0.16 | 0.01 |
| NANb | Ŷ = 1.0905 + 0.03793 × CP | 172 | 0.04 | 0.79 | 0.04 |
| Bacterial-N | Ŷ = 0.9246 + 0.002654 × CP | –18 | 0.03 | 0.83 | 0.02 |
| Dietary | Ŷ = 0.7082 | 24.7 | 0.13 | — | >0.05 |
| EMPSc | Ŷ = 21.9473 + 0.3668 × CP | 2,724 | 25.0 | 018 | 0.02 |
AIC = Akaike information criteria; MSE = mean square error.
aVolatile fatty acids.
bNon-ammonia nitrogen.
cEfficiency of microbial protein synthesis, calculated as g of bacterial nitrogen/ kg of organic matter truly digested.
d P-value of the model.