Table 6.
Characterization of rumen fermentation profile in finishing beef cattle ranked for residual methane emissions, sex, and genotype
| RME ranking1 | Sex | Genotype | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Rumen fermentation2 | Mean | SD | High, n = 84 | Medium, n = 114 | Low, n = 84 | SEM3 | Steers, n = 128 | Heifers, n = 154 | SEM3 | Late, n = 219 |
Early, n = 63 |
SEM3 | P-value, RME ranking | P-value, sex | P-value, genotype |
| pH | 6.8 | 0.3 | 6.8 | 6.8 | 6.8 | 0.1 | 6.8 | 6.8 | 0.1 | 6.8 | 6.8 | 0.1 | 0.48 | 0.76 | 0.10 |
| Total SCFA, mM | 124.2 | 34.4 | 134.5a | 120.9b | 119.9b | 7.2 | 119.8 | 130.4 | 8.9 | 123.4 | 126.8 | 6.9 | 0.02 | 0.39 | 0.54 |
| Acetate, % | 74.3 | 6.7 | 73.6 | 73.1 | 73.5 | 1.5 | 71.9 | 74.9 | 1.9 | 73.7 | 73.1 | 1.4 | 0.85 | 0.26 | 0.51 |
| Propionate, % | 13.0 | 4.3 | 13.0a | 14.0a | 14.5b | 1.2 | 14.4 | 13.2 | 1.5 | 13.7 | 13.9 | 1.1 | 0.04 | 0.59 | 0.66 |
| Butyrate, % | 7.8 | 2.6 | 8.0 | 7.8 | 7.1 | 0.7 | 7.7 | 7.5 | 0.9 | 7.5 | 7.7 | 0.69 | 0.10 | 0.89 | 0.56 |
| A:P | 5.7 | 1.4 | 6.7a | 5.8b | 5.7b | 0.6 | 5.2 | 7.0 | 0.8 | 6.3 | 5.9 | 0.6 | 0.03 | 0.11 | 0.31 |
| Hydrogen production, mM | 663.7 | 157.2 | 688.6a | 622.9b | 630.7b | 37.6 | 626.5 | 668.3 | 48.0 | 654.8 | 640.0 | 36.5 | 0.03 | 0.54 | 0.56 |
1High, RME were >0.5 SD above the mean; medium, RME was ±0.5 SD above and below the mean; low, RME was >−0.5 SD below the mean.
2A:P, acetate to propionate ratio.
3SEM, pooled standard error.
a,bLeast squares means within main effect and a row with different superscripts differ.