TABLE 1.

Effect of regions located at distinct altitudes on yak rumen fermentation parameters.

Parameters	Groups1			SEM	P-value
	HAL	MAL	LAL
PH	6.41	6.54	6.45	0.042	0.834
T-VFA (mmol/L)	49.62b	69.41a	45.22b	2.943	< 0.001
Acetic acid (%)	74.58a	61.73b	72.09a	0.011	< 0.001
Propionic acid (%)	15.88b	24.46a	18.21b	0.008	< 0.001
Butyric acid (%)	9.54b	13.81a	9.70b	0.005	< 0.001
A/P	4.73a	2.57b	3.97a	0.18	< 0.001

¹HAL, high-altitude region (Zhongba County, Xigatse City; 4,800 m); MAL, medium-altitude region (Nagqu City; 4,500 m); LAL, low-altitude region (Dangxiong County, Lhasa City; 3,800 m). T-VFA, total volatile fatty acids; A/P, acetic acid/propionic acid.

Different superscript letters in the same row denote significant differences (p < 0.05).