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 |