Table 2
Influence of dietary treatments on characteristics of digestion

	Urea fermentation potential			P -value
Item	0	0.6	1.2	Linear	Quadratic	SEM
Steer replications	6	6	6
Intake (g/d)
DM	3556	3553	3551
OM	3343	3359	3378
NDF	453	455	457
N	66.2	57.6	48.2
Starch	1907	1919	1932
GE (Mcal/d)	15.2	15.2	15.3
Flow to the duodenum (g/d)
OM	1655	1749	1894	0.05	0.76	83.0
NDF	338	370	456	0.05	0.55	42.0
Starch	385	441	533	0.08	0.77	61.0
Total N	76.4	68.8	64.4	0.04	0.70	4.0
Microbial N	40.6	34.7	31.4	0.04	0.69	3.0
NH-N	2.30	2.04	1.58	0.06	0.72	0.3
Non-ammonia N	74.1	66.7	62.9	0.04	0.66	3.8
Feed N	24.7	23.2	22.7	0.20	0.71	0.9
Ruminal digestibility, %
OM	62.6	58.3	53.23	0.04	0.91	0.3
NDF	25.3	18.6	0.30	0.05	0.54	0.9
Starch	79.8	77.0	72.4	0.09	0.78	0.3
Feed N	62.6	59.7	52.9	0.04	0.64	0.5
Microbial efficiency1	19.4	17.8	17.5	0.06	0.40	0.7
N efficiency2	1.12	1.16	1.30	0.05	0.44	0.07
Fecal excretion (g/d)
OM	624	705	756	0.06	0.77	48.0
NDF	282	319	348	0.06	0.87	25.0
Starch	35.9	49.0	56.6	0.10	0.78	9.4
Total N	20.9	22.2	21.8	0.48	0.44	1.0
GE (Mcal/d)	3.28	3.66	3.90	0.05	0.75	0.84
Postruminal digestibility (% of flow to duodenum)
OM	62.2	59.7	60.0	0.37	0.49	1.9
NDF	15.3	11.2	22.8	0.41	0.33	7.3
Starch	90.5	89.1	89.3	0.60	0.69	1.9
Total N	72.6	67.6	66.2	0.08	0.53	2.7
Total tract digestibility (% of intake)
OM	81.3	79.0	77.6	0.06	0.75	1.4
NDF	37.8	29.8	23.9	0.07	0.85	5.3
Starch	98.1	97.4	97.1	0.11	0.77	0.5
Total N	68.5	61.5	54.9	0.04	0.97	4.5
DE, %	78.5	76.0	74.5	0.05	0.74	1.4
DE, Mcal/kg	3.36	3.26	3.20	0.05	0.73	0.06