Table 6.

Ruminal pH in feedlot cattle fed diets varying in percentage of barley silage measured for 6 days using indwelling pH data loggers

	Barley silage, % of dietary DM					P-value1
Item	0	4	8	12	SEM	Silage	Linear	Quadratic
Ruminal pH
Minimum	5.07	5.27	5.29	5.41	0.082	0.003	0.043	0.011
Mean	5.61	5.87	5.93	5.95	0.144	<0.001	<0.001	0.007
Maximum	6.38	6.50	6.57	6.56	0.143	0.005	0.004	0.15
Range	1.31	1.23	1.28	1.15	0.091	0.33	0.99	0.12
Duration, h/d
pH < 5.8	16.7	11.4	9.8	8.3	3.64	<0.001	<0.001	0.002
pH < 5.5	11.3	4.2	4.2	4.0	2.41	<0.001	<0.001	0.002
pH < 5.2	3.66	0.51	0.88	1.00	0.684	0.001	0.001	0.009
Area, pH × h/d
pH < 5.8	6.99	2.98	2.84	2.67	1.456	<0.001	<0.001	0.001
pH < 5.5	2.72	0.64	0.77	0.85	0.527	<0.001	<0.001	0.002
pH < 5.2	0.503	0.064	0.105	0.148	0.1018	0.011	0.006	0.047
Acidosis index, (pH × h/d)/kg DMI
pH < 5.5	0.263	0.060	0.067	0.074	0.0497	<0.001	<0.001	0.001
pH < 5.2	0.049	0.006	0.009	0.013	0.0098	0.006	0.003	0.035

¹ P-values indicate overall silage, linear, and quadratic effects. There was no day (P ≥ 0.26) or day × diet (P ≥ 0.13) effect on pH variables.