Table 4.
Diet digestibility in growing beef steers fed diets of varying F:C at ad libitum intake
| Treatment1 | P-value | |||||||
|---|---|---|---|---|---|---|---|---|
| Item | HF:C | IF:C | EF:C | LF:C | VLF:C | SEM2 | Linear | Quadratic |
| Dry matter digestibility, % | 61.8 | 62.7 | 65.3 | 69.3 | 73.6 | 1.54 | <0.01 | 0.06 |
| OM | ||||||||
| Intake, g/d | 6,888.5 | 7,321.2 | 7,943.6 | 7,206.5 | 8,050.9 | 397.3 | 0.01 | 0.47 |
| Fecal excretion, g/d | 2,376.9 | 2,519.7 | 2,500.7 | 2,065.8 | 1,916.2 | 182.9 | 0.01 | 0.07 |
| Digested, g/d | 4,514.1 | 4,824.7 | 5,421.8 | 5,163.9 | 6,113.5 | 294.4 | <0.01 | 0.55 |
| Digestibility, % of intake | 66.0 | 65.8 | 68.4 | 72.3 | 75.7 | 1.64 | <0.01 | 0.08 |
| NDF | ||||||||
| Intake, g/d | 3,047.6 | 3,156.2 | 3,020.2 | 2,192.6 | 2,362.9 | 152.50 | <0.01 | 0.01 |
| Fecal excretion, g/d | 1,856.6 | 1,699.8 | 1,524.8 | 1,098.3 | 890.1 | 91.05 | <0.01 | 0.02 |
| Digested, g/d | 1,197.0 | 1,462.4 | 1,494.5 | 1,100.3 | 1,471.8 | 93.84 | 0.44 | 0.13 |
| Digestibility, % of intake | 40.0 | 46.0 | 49.9 | 50.2 | 62.7 | 1.88 | <0.01 | 0.10 |
| ADF | ||||||||
| Intake, g/d | 1,890.3 | 1,866.6 | 1,815.8 | 1,104.7 | 794.5 | 91.93 | <0.01 | <0.01 |
| Fecal excretion, g/d | 1,260.5 | 1,118.3 | 952.6 | 679.0 | 494.5 | 56.97 | <0.01 | 0.03 |
| Digested, g/d | 640.2 | 758.3 | 862.1 | 435.6 | 298.9 | 60.67 | <0.01 | <0.01 |
| Digestibility, % of intake | 33.3 | 40.0 | 47.1 | 38.9 | 35.3 | 2.94 | 0.58 | <0.01 |
| Starch | ||||||||
| Intake, g/d | 1,568.0 | 1,976.7 | 2,287.3 | 2,863.4 | 3,852.5 | 194.99 | <0.01 | 0.01 |
| Fecal excretion, g/d | 1.1 | 109.3 | 161.9 | 221.7 | 256.0 | 35.79 | <0.01 | 0.40 |
| Digested, g/d | 1,564.6 | 1,867.5 | 2,123.3 | 2,641.8 | 3,594.3 | 190.19 | <0.01 | <0.01 |
| Digestibility, % of intake | 99.7 | 94.4 | 92.7 | 92.1 | 93.3 | 1.28 | <0.01 | <0.01 |
1DRC replaced corn silage and alfalfa hay at 0% (HF:C), 22.5% (IF:C), 45% (EF:C), 67.5% (LF:C), and 83.8% (VLF:C) of dietary DM.
2Pooled standard error of the least-squares mean (n = 10 except in period 3 n = 9).