Table 1.
Composition and nutrient levels of the experimental diets (on a dry matter basis)
| Items | Treatments | ||
|---|---|---|---|
| L | M | H | |
| Ingredient | |||
| Chinese wildrye | 12.50 | 12.50 | 12.50 |
| Dry alfalfa hay | 16.50 | 16.50 | 16.50 |
| Corn silage | 21.00 | 21.00 | 21.00 |
| Corn | 12.90 | 18.12 | 27.85 |
| Wheat bran | 12 | 10 | 8.29 |
| Soybean meal | 5 | 4.44 | 4 |
| DDGS a | 5 | 5 | 4.86 |
| Cottonseed meal | 4.02 | 3 | 3 |
| Rice hull powder | 9.08 | 7.44 | 0 |
| Premixb | 2.00 | 2.00 | 2.00 |
| Total | 100.00 | 100.00 | 100.00 |
| Nutrient level | |||
| Dry matter (%) | 89.43 | 89.45 | 89.64 |
| Metabolizable energyc(MJ/kg) | 9.34 | 10.08 | 10.88 |
| CPd (%) | 14.09 | 14.06 | 14.12 |
| NDF d (%) | 50.52 | 48.27 | 42.74 |
| ADF d (%) | 35.13 | 33.41 | 29.19 |
| Ash (%) | 7.61 | 6.93 | 5.69 |
| Calcium (%) | 0.97 | 0.94 | 0.92 |
| Phosphorous (%) | 0.46 | 0.46 | 0.46 |
aDDGS, distillers dried grains with soluble
bManufactured by the Precision Animal Nutrition Research Centre, Beijing, China. Premix provided the following per kg of concentrate: vitamin A, 30150 IU; vitamin D, 9675 IU; vitamin E, 76.5 mg; Fe, 132 mg; Cu, 26 mg; Mn, 118.30 mg; Zn, 166 mg; Se, 0.07 mg; I, 0.11 mg; Co, 0.03 mg; Ca, 6.76 g; P, 0.68 g
cMetabolizable energy was calculated according to the Nutrient Requirements of Dairy Cattle (NRC, 2001)
dCP, Crude protein; NDF, Neutral detergent fiber; ADF, Acid detergent fiber