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.