Table 5.

Effect of C₁₈ fatty acid source in the supplementary concentrate and measurement period on methane emissions from lactating dairy cows offered a pasture based diet (least square means ± SEM).

Methane (CH4) Variable	Treatment 1				Measurement Period (MP) 2			p-Value
	SA	SO	LO	SEM	1	2	SEM	Treatment	MP	Treatment x MP
Total CH4, g/d	293 a	289 a	245 b	8.9	241	311	7.2	0.002	<0.001	0.15
g CH4/kg milk	15.7 a	14.8 a	12.4 b	0.5	12.3	16.3	0.4	<0.001	<0.001	0.14
g CH4/kg milk solids	207 a	195 a	165 b	6.3	166	211	5	<0.001	<0.001	0.12
g CH4/kg DMI 3	17.9 a	18.7 a	16.3 b	0.51	15.2	20.0	0.42	0.004	<0.001	0.02
g CH4/g of added FA 4	0.46 a	0.45 a	0.40 b	0.16	0.38	0.49	0.01	0.02	<0.001	0.19
CH4/GEI 5, MJ/MJ	0.052 a,b	0.055 a	0.047 b	0.0015	0.045	0.058	0.0012	0.002	<0.001	0.02

¹ SA = supplementary concentrate containing 16% FW stearic acid; SO = supplementary concentrate containing 16% FW soy oil; LO = supplementary concentrate containing 16% FW linseed oil; ² MP = measurement period, MP 1 corresponds to 17 to 22 d post treatment introduction and MP 2 corresponds to 44 to 49 d after treatment introduction; ³ DM = dry matter; OM = organic matter; CP = crude protein; NDF = neutral detergent fiber; ADF = acid detergent fiber; ADL = acid detergent lignin; WSC = water soluble carbohydrates; ³ DMI = dry matter intake; ⁴ FA = fatty acids; ⁵ GEI = gross energy intake. ^a,b Means within rows differ significantly.