Table 4.
Comparison of animal performance, diet, and enteric methane emission data from studies with different methods to quantify enteric methane emission in lactating dairy cows.
| Item 1 | Method 2 | p-Value 3 | |||
|---|---|---|---|---|---|
| Respiration Chamber | SF6 | GreenFeed® | Other | ||
| Animal | |||||
| Metabolic weight (BW0.75), kg | 128.98 a ± 1.11 (n = 188) |
125.00 b ± 1.11 (n = 114) |
131.46 a ± 1.44 (n = 52) |
134.16 a ± 3.28 (n = 8) |
<0.01 |
| Milk yield (MY), kg/day | 31.82 b ± 0.91 (n = 192) |
29.63 c ± 0.91 (n = 132) |
35.46 a ± 1.23 (n = 52) |
33.12 abc ± 2.81 (n = 8) |
<0.01 |
| Milk protein, g/kg | 32.94 a ± 0.19 (n =161) |
31.99 ab ± 0.23 (n = 105) |
32.03 ac ± 0.38 (n = 40) |
34.85 ac ± 1.69 (n = 2) |
<0.01 |
| Milk fat, g/kg | 39.91 ab ± 0.58 (n = 169) |
38.25 a ± 0.61 (n = 111) |
38.99 ab ± 0.85 (n = 40) |
43.01 ab ± 3.52 (n = 2) |
0.04 |
| DMI, kg/day | 21.06 b ± 0.41 (n = 191) |
20.76 b ± 0.43 (n = 125) |
23.42 a ± 0.62 (n = 40) |
23.25 ab ± 1.72 (n = 4) |
<0.01 |
| Diet | |||||
| Forage in diet, g/kg DM | 596.56 a ± 12.33 (n = 178) |
543.79 b ± 14.92 (n = 64) |
569.28 ab ± 17.78 (n = 42) |
623.83 a ± 38.94 (n = 8) |
<0.01 |
| NDF, g/kg DM | 346.53 ± 7.32 (n = 163) |
344.78 ± 8.02 (n = 81) |
344.11 ± 10.35 (n = 42) |
397.69 ± 25.40 (n = 6) |
0.23 |
| Crude protein, g/kg DM | 166.70 ± 1.37 (n = 182) |
165.66 ± 2.25 (n = 68) |
171.20 ± 2.79 (n = 44) |
159.00 ± 7.56 (n = 6) |
0.29 |
| Ether extract, g/kg DM | 42.58 a ± 1.52 (n = 134) |
36.09 b ± 2.45 (n = 35) |
34.24 b ± 2.90 (n = 25) |
28.02 b ± 6.97 (n = 4) |
<0.01 |
| Starch, g/kg DM | 191.96 ± 9.11 (n = 113) |
204.93 ± 11.97 (n = 48) |
211.56 ± 16.77 (n = 23) |
164.38 ± 36.65 (n = 4) |
0.42 |
| OM digestibility, g/kg | 709.81 a ± 7.57 (n = 105) |
674.03 b ± 8.17 (n = 44) |
691.87 ab ± 10.70 (n = 26) |
693.48 ab ± 32.24 (n = 2) |
<0.01 |
| Methane Enteric Emission | |||||
| Production, g/cow/day | 445.3 a ± 10.61 (n = 218) |
406.0 b ± 10.75 (n = 142) |
470.0 a ± 14.52 (n = 53) |
458.0 a ± 38.32 (n = 6) |
<0.01 |
| SEM, g/cow/day | 22.28 b ± 1.97 (n = 207) |
27.55 a ± 2.03 (n = 136) |
22.32 b ± 2.92 (n = 45) |
13.42 b ± 7.48 (n = 6) |
0.03 |
| Yield, g/kg DMI | 21.20 ± 0.47 (n = 191) |
20.19 ± 0.50 (n = 125) |
20.55 ± 0.77 (n = 40) |
17.89 ± 2.23 (n = 4) |
0.13 |
| Intensity, g/kg MY | 14.53 ± 0.36 (n = 192) |
15.38 ± 0.44 (n = 132) |
14.35 ± 0.69 (n = 52) |
13.53 ± 2.04 (n = 6) |
0.38 |
1 DMI = dry matter intake; NDF = neutral detergent fiber; OM = organic matter; SEM = standard error of mean. 2 Least squares mean ± standard error (n = observation). 3 F-test to compare studies with different enteric methane emission methods. a–c Means values in the same row with different superscripts differ (p < 0.01).