Table 1. Methane (CH₄), hydrogen (H₂) and carbon dioxide (CO₂) emissions from lambs fed fresh winter forage rape or fresh perennial ryegrass for 48 h periods in open circuit respiration chambers.

Intakes and emissions	Forage rape	Perennial ryegrass	P b
	(n = 24) a	(n = 18)
Period 1
DM c intake (g/d)	862 ±8.1	792 ±25.9	0.006
CH4 (g/d)	11.7 ±0.48	15.4 ±0.97	<0.001
CH4 (g/kg DM intake)	13.6 ±0.52	19.5 ±1.14	<0.001
CH4 energy loss/gross energy intake	0.050 ±0.0019	0.063 ±0.0039	0.002
CH4 (g/LW d )	0.316 ±0.0117	0.447 ±0.0139	<0.001
CH4 (g/LW0.75)	0.843 ±0.0308	1.167 ±0.0367	<0.001
H2 (g/kg DM intake)	0.026 ±0.004	0.010 ±0.001	0.109
CO2 (g/kg DM intake)	1005 ±6.8	1019 ±22.2	0.480
CH4/CO2 (mol/mol)	0.039 ±0.0014	0.052 ±0.0030	<0.001
Period 2
DM intake (g/d)	896 ±8.4	929 ±20.8	0.116
CH4 (g/d)	16.0 ±0.60	21.2 ±0.50	<0.001
CH4 (g/kg DM intake)	17.8 ±0.64	22.9 ±0.45	<0.001
CH4 energy loss/gross energy intake	0.058 ±0.0021	0.073 ±0.0014	<0.001
CH4 (g/LW d )	0.304 ±0.0108	0.392 ±0.0124	<0.001
CH4 (g/LW0.75)	0.758 ±0.0272	0.981 ±0.0314	<0.001
H2 (g/kg DM intake)	0.037 ±0.008	0.033 ±0.006	0.746
CO2 (g/kg DM intake)	1190 ±10.7	1065 ±16.3	<0.001
CH4/CO2 (mol/mol)	0.041 ±0.0014	0.058 ±0.0011	<0.001

^a Number of animals sampled. Values are means ± SEM.

^b P value for the difference between forage rape and perennial ryegrass.

^c Dry matter.

^d Live weight.