Table 2. Effects of shrub coverage on rumen pH and fermentation parameters of yaks grazed on an alpine meadow
Item | Shrub coverage | SEM | p-value |
Control | Low | Middle | High | Treatment | Linear | Quadratic |
Rumen pH | 5.65 | 5.75 | 5.27 | 5.82 | 0.128 | 0.886 | 0.990 | 0.403 |
NH3-N (mg/100 mL) | 4.48b | 4.69b | 9.36a | 9.48a | 0.802 | 0.008 | 0.004 | 0.970 |
Total VFA (mmol/mL) | 95.7 | 84.6 | 130.5 | 116.4 | 9.74 | 0.356 | 0.247 | 0.938 |
Acetate (%) | 72.8 | 74.1 | 70.1 | 70.6 | 0.89 | 0.483 | 0.219 | 0.840 |
Propionate (%) | 16.4 | 15.4 | 16.5 | 15.7 | 0.38 | 0.845 | 0.811 | 0.911 |
Butyrate (%) | 7.53 | 7.07 | 9.08 | 8.54 | 0.403 | 0.067 | 0.188 | 0.959 |
Isobutyrate (%) | 1.11b | 1.13b | 1.36ab | 1.68a | 0.096 | 0.042 | 0.038 | 0.404 |
Isovalerate (%) | 1.58b | 1.67b | 2.12ab | 2.58a | 0.156 | 0.041 | 0.018 | 0.716 |
Valerate (%) | 0.59b | 0.64ab | 0.87a | 0.86a | 0.048 | 0.028 | 0.017 | 0.513 |
Acetate:propionate | 4.52 | 4.83 | 4.39 | 4.52 | 0.169 | 0.808 | 0.791 | 0.810 |
Values within a row with different superscripts differ significantly at p < 0.05.
SEM, standard error of the mean; NH3-N, ammonia nitrogen; VFA, volatile fatty acids.