Table 4.

Effects of K₂CO₃ on rumen fermentation parameters of lactating cows.

Items	Groups1				SEM	P-value
	CON	LD	MD	HD		ANOVA	Linear	Quadratic
pH	6.36	6.49	6.53	6.54	0.029	0.094	0.021	0.041
Acetate, mmol/L	54.96b	60.52a	61.97a	63.22a	0.990	0.008	0.001	0.003
Propionate, mmol/L	33.60	34.17	35.97	33.28	0.467	0.172	0.035	0.080
Isobutyrate, mmol/L	1.56	1.33	1.48	1.38	0.071	0.697	0.552	0.764
Butyrate, mmol/L	14.06b	14.55b	15.24b	18.87a	0.589	0.007	0.002	0.002
Isovalerate, mmol/L	1.45b	1.66b	2.27a	2.37a	0.105	<0.001	<0.001	<0.001
Valerate, mmol/L	1.65	1.83	1.83	1.91	0.077	0.692	0.255	0.504
Total VFA, mmol/L	109.96	114.04	116.39	121.02	1.549	0.072	0.007	0.029
Acetate:propionate	1.53b	1.77a	1.85a	1.91a	0.038	<0.001	<0.001	<0.001

VFA = volatile fatty acids.

Superscripts differing across the same row denote significant differences (P < 0.05).

¹CON, the control group (basal diet); LD, the low dose group (basal diet + 250 g/d K₂CO₃·1.5H₂O per head); MD, the medium dose group (basal diet + 500 g/d K₂CO₃·1.5H₂O per head); HD, the high dose group (basal diet + 750 g/d K₂CO₃·1.5H₂O per head).