Table 6.

Rumen pH and VFA profile of steers fed high and low intakes with two levels of monensin inclusion

	Lowa		High			Probabilityb
Item	0	200	0	200	SEMc	Monensin	Intake	Time	M × I	M × T	I × T
Ruminal pH	6.4	6.58	6.27	6.39	0.054	0.02	0.01	<0.01	0.62	0.13	<0.01
Molar proportion
Acetate	63.87	59.74	65.66	58.01	0.863	<0.01	0.94	<0.01	0.07	0.03	0.07
Propionate	21.20	24.02	21.02	26.05	0.921	<0.01	0.33	<0.01	0.25	<0.01	0.14
Butyrate	10.84	11.09	9.62	11.31	0.653	0.16	0.46	<0.01	0.29	0.01	0.24
Isobutyrate	1.22	1.54	1.08	1.38	0.036	<0.01	<0.01	<0.01	0.70	<0.01	0.01
Isovalerate	1.88	2.64	1.64	2.13	0.183	<0.01	0.06	<0.01	0.48	<0.01	<0.01
Valerate	0.99	0.96	0.98	1.04	0.047	0.76	0.49	<0.01	0.36	<0.01	0.07
Acetate:propionate	3.04	2.51	3.16	2.28	0.136	<0.01	0.71	<0.01	0.21	<0.01	0.04
Concentration, mM
Acetate	52.07	41.89	57.01	44.93	1.589	<0.01	0.03	<0.01	0.56	<0.01	<0.01
Propionate	17.32	16.82	18.28	20.38	1.019	0.45	0.05	<0.01	0.23	<0.01	<0.01
Total VFA	81.67	69.98	86.79	77.54	2.595	<0.01	0.03	<0.01	0.65	<0.01	<0.01

^aLow = received 80% NRC requirements; high = received 120% NRC requirements; 0 = 0 mg/d monensin inclusion; 200 = 200 mg/d monensin inclusion.

^bMonensin = effect of 0 vs. 200; intake = effect of low vs. high; M × I × T interaction for acetate proportion (P = 0.03); all others (P > 0.10).

^c n = 4.