Table 4. Feeding method effects on methane production, methane conversion factor, methane emission factor, and ruminal fermentation yields in Hanwoo steers

Variables	Diets		SEM	p-value
	SF (n = 8)	TMR (n = 8)
Methane production (g/d)	161.41	167.60	8.62	0.213
Methane production (L/d)	225.37	234.01	12.04	0.183
Methane yield (g/d/kg)
DMI	21.00	22.86	0.74	0.176
OMI	22.28	24.49	0.75	0.154
dDMI	29.95	31.92	1.00	0.307
dOMI	31.19	33.53	0.99	0.265
dNDFI	133.16	124.06	4.32	0.291
MCF1) (%)	6.43	7.07	0.23	0.135
MEF2) (methane/head/year kg)	57.59	61.18	3.11	0.089
pH	6.91	6.76	0.08	0.209
Ammonia nitrogen (mg/dL)	8.86	6.81	0.65	0.474
Total volatile fatty acids (mM)	53.55	60.26	4.81	0.287
Acetate (mM)	31.80	36.95	3.02	0.227
Propionate (mM)	13.38	14.02	1.31	0.605
Butyrate (mM)	8.38	9.29	0.76	0.197
Acetate:Propionate ratio	2.48	2.67	0.12	0.460

Methane conversion factor = gross energy percent in feed converted to methane [1].
Methane emission factor = (MJ/head/d of gross energy intake) × (MCF ÷ 100) × 365 ÷ (55.65 MJ/kg of methane) [1].
SF, separate feeding concentrate and forage; TMR, total mixed ration; DMI, dry matter intake; OMI, organic matter intake; dDMI, digestible dry matter intake; dOMI, digestible organic matter intake; dNDFI, digestible neutral detergent fiber intake.