Table 2.

Effect of diet (D) and period (P) on volatile fatty acid (VFA) levels^a in rumen fluid

	RES		ADLIB			Significance
	Period 1	Period 2	Period 1	Period 2	SEMb	D	P	D*Pc
Molar Proportions, mmol/L VFA
Acetic Acid	60.9	67.79	52.14	77.57	6.875	0.942	0.024	0.186
Propionic Acid	13.98	28.44	20.1	34.75	2.506	0.018	<0.001	0.968
N-Butyric Acid	10.5	11.09	6.02	13.84	1.895	0.653	0.033	0.064
Iso-Butyric Acid	1.84	0.15	1.1	0.54	0.202	0.351	<0.001	0.562
N-Valeric Acid	0.88	2.18	1.38	2.87	0.261	0.029	<0.001	0.708
Iso-Valeric Acid	2.31	1.55	2.31	1.97	0.244	0.386	0.029	0.388
Total, mmol/L VFA	90.42	111.18	83.04	131.55	9.831	0.513	0.001	0.167
Acetate:Propionate Ratio	4.4	2.4	2.6	2.2

^aRuminal fluid samples were taken from 5 different points within the rumen of each bull at slaughter and VFA levels were measured using an automated gas chromatograph

^bSEM, standard error of the mean

^cD*P, diet × period interaction