Table 3.

Production of volatile fatty acids by in vitro cultures containing ruminal contents from control-fed and crude glycerin-fed steers, when cultures were fed substrates consisting of diets containing 0 or 15% crude glycerin (Exp. 1)

Item, mM	Control-fed rumen fluid		Crude glycerin-fed rumen fluid		P-value3
	CON1	15CG2	CON	15CG	Diet	Substrate	D×S
Total VFA	24.2	25.2	12.4	27.9	0.47	0.20	0.26
Acetate	18.3	12.4	6.9	13.3	0.29	0.95	0.22
Propionate	4.2	7.7	3.5	9.8	0.54	<0.01	0.23
Butyrate	1.6	4.1	1.8	3.7	0.91	<0.01	0.70
Isobutyrate	0.03	0.14	0.16	0.18	0.41	<0.01	0.99
Valerate	0.22	0.66	0.24	0.64	0.98	<0.01	0.87
Isovalerate	0.04	0.17	0.19	0.17	0.88	0.01	0.83

¹CON = Control diet, without crude glycerin.

²15CG = 15% added crude glycerin.

³Diet = Finishing diet fed to donor animals, Substrate = Diet that was included in the in vitro fermentations, D×S = Interaction of diet of the donor animal and substrate fed to the in vitro culture.