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Table 3 Effects of diets and incubation time on in vitro degradability of NDF (NDFd) and of true DM (TDMd), gas production (GP) and methane (CH4) production, and predicted values of GP and CH4 production

From: Influence of main dietary chemical constituents on the in vitro gas and methane production in diets for dairy cows

  Degradability Actual GP, ml per: Actual CH4 mL per Predicted GP Predicted CH4
NDFd, g/kg NDF TDMd, g/kg DM g DM g TDMd g DM g dNDF g TDMd 100 mL GP mL/g DM mL/g DM
Diet
 Reference 567 840 274 325 34.2 168 40.8 12.5 244 38.8
 Low NDF 612A 872A 288A 331 34.4 174 39.3 11.9 250 39.6
 High NDF 480B 767B 228B 300B 30.8B 151B 39.9 13.5A 220 35.9
 Low CP 545 835 277 333 33.4 169 39.9 12.0 242 38.0
 High CP 542 831 255B 310 34.0 176 41.0 13.3A 234 37.8
 Low lipid 583 845 265 315 33.1 159 39.0 12.3 251 37.2
 High lipid 531 826 253B 304B 32.2B 169 38.8 12.5 238 37.9
  SEM 10.3 4.2 5.6 7.2 0.53 3.4 0.63 0.40 10.9 2.09
P-value <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 0.025 <0.001 0.33 0.70
P-value of contrasts
 Low vs High NDF <0.001 <0.001 <0.001 <0.001 <0.001 0.002 0.99 <0.001 0.99 0.99
 Low vs High CP 0.99 0.99 <0.001 0.009 0.99 0.99 0.99 <0.001 0.99 0.99
 Low vs High lipid 0.003 0.028 0.017 0.99 0.99 0.99 0.99 0.99 0.99 0.99
Incubation time
 24 h 472 801 250 314 29.6 172 37.0 11.9 214 34.9
 48 h 631 860 276 320 36.7 161 42.6 13.2 260 41.5
  SEM 10.5 3.5 7.4 8.8 0.59 1.8 0.66 0.54 7.6 1.69
P-value 0.009 0.007 0.14 0.69 0.014 0.046 0.027 0.22 0.06 0.12
RMSE 15.5 7.2 4.0 7.6 0.69 3.2 0.94 0.25 21.9 3.78
  1. Values with different superscripts within column are significantly (P < 0.05) higher (A) or lower (B) compared to the reference diet (containing 361, 158, and 33 g/kg DM of NDF, CP, and lipids)
  2. Low NDF low NDF diet (325 g/kg DM), High NDF high NDF diet (435 g/kg DM), Low CP low protein diet (CP, 115 g/kg DM), High CP high protein diet (CP, 194 g/kg DM), Low lipid low lipid diet (EE, 26 g/kg DM), High lipid high lipid diet (EE, 61 g/kg DM)