Table 2.

Effects of diet, time of collection of sample and their interaction on ruminal pH and fermentation parameters in ruminal fluid collected from Holstein calves fed a control diet (CTR) and a nitrate-containing diet (NIT).

Item	Diet		SEM	P-value
	CTR	NIT		Diet	Time	D × T
pH	6.8	6.8	0.03	0.753	0.001	0.136
NH3–N, mg/dL	8.5	10.2	0.35	0.047	0.002	0.001
Total VFA, mmol/L	236.2	228.4	8.23	0.253	0.036	0.092
Fermentation profile, %
Acetate	69.6	75.3	0.55	0.009	0.279	0.001
Propionate	20.9	14.9	0.49	0.010	0.245	0.001
Butyrate	6.2	6.9	0.19	0.198	0.817	0.149
Iso-butyrate	1.3	0.8	0.13	0.115	0.255	0.308
Valerate	0.6	0.4	0.02	0.037	0.917	0.165
Iso-valerate	1.3	1.4	0.05	0.748	0.411	0.098
A/P ratio	3.7	5.4	0.14	0.005	0.196	0.001

D × T = Diet × Time interaction; NH₃–N = ammonia nitrogen; VFA = Volatile fatty acids; A/P = acetate to propionate ratio.