Table 4.

Effect of inoculum and ammoniation treatment (trt) of barley straw on gas production and fermentation variables (pH, total VFA and individual VFA).

Item	Treatment1					P-value
	Untreated		AFEX		SEM	Trt2	Inoculum	Int2
	Slow	Fast	Slow	Fast
Gas production
Total, L/d	1.54	1.61	1.59	1.60	0.135	0.87	0.76	0.79
CH4, %	6.20	6.37	6.14	6.11	0.534	0.66	0.88	0.79
CH4, mL/d	94.2	101	94.1	105	14.4	0.83	0.23	0.83
CH4, mg/d	61.2	66.0	61.2	67.6	9.30	0.87	0.26	0.86
CH4, mg/g incubated DM	6.66	7.19	6.65	7.32	0.973	0.91	0.26	0.88
CH4, mg/g digested DM	11.7	12.9	9.67	10.8	1.49	0.046	0.22	0.98
pH	6.70	6.69	6.64	6.61	0.019	<0.001	0.095	0.34
Ammonia, mg/d	110	98.3	137	131	5.29	<0.001	0.015	0.45
Total VFA, mmol/d	50.6c3	49.0c	57.4b	59.6a	1.88	<0.001	0.67	0.035
VFA, mol/100 mol
Acetate (A)	66.1a	63.9b	63.7b	64.1b	0.618	0.001	0.006	<0.001
Propionate (P)	22.6	23.8	25.9	26.2	0.603	<0.001	0.021	0.21
Butyrate	7.22b	8.28a	6.74c	6.17d	0.098	<0.001	0.025	<0.001
Valerate	1.62	1.66	1.40	1.34	0.042	<0.001	0.60	0.10
Isobutyrate	0.916	0.933	0.849	0.848	0.012	<0.001	0.55	0.48
Isovalerate	1.51	1.44	1.33	1.30	0.035	<0.001	0.19	0.52
Caproate (×10-2)	4.52c	4.59c	5.19a	4.98b	0.011	<0.001	0.21	0.018
A:P ratio	2.93a	2.69b	2.47c	2.45c	0.090	<0.001	0.012	0.029

¹Fast refers to inoculum from animals with fast rate of NDFD; slow refers to animals with slow rate of NDFD.

²Trt refers to straw treatment: AFEX or untreated; Int refers to interaction between treatment and inoculum.

³‘a, b, c, and d’ Values within a row with the same letter do not differ (P > 0.05).