Table 2. Ingredients and chemical composition of experimental diets.
| Item | Crude protein concentration (g Kg-1 DM) | |||
|---|---|---|---|---|
| 156 | 139 | 132 | 127 | |
| Ingredients (g Kg-1) | ||||
| Corn silage | 536 | 540 | 533 | 530 |
| Corn meal | 296 | 316 | 324 | 323 |
| Soybean meal | 133 | 83 | 70 | 53 |
| Urea | 87 | 57 | 29 | 0 |
| Soypass®(1) | 0 | 29 | 44 | 68 |
| Sodium bicarbonate | 7 | 7 | 7 | 7 |
| Mineral-vitamin supplement(2) | 19 | 19 | 19 | 19 |
| Chemical composition | ||||
| Dry matter (DM, g Kg-1 organic matter) | 582 | 580 | 583 | 585 |
| Crude protein (g Kg-1 DM) | 156 | 139 | 132 | 127 |
| Gross energy (Kcal kg-1) | 3.94 | 3.94 | 3.95 | 3.96 |
| Non-fiber carbohydrate (g Kg-1 DM) | 413 | 427 | 435 | 438 |
| Neutral detergent fiber (g Kg-1 DM) | 353 | 356 | 355 | 358 |
| Acid detergent fiber (g Kg-1 DM) | 161 | 161 | 161 | 162 |
| Ether extract (g Kg-1 DM) | 33 | 33 | 33 | 33 |
| Rumen-degradable protein (g Kg-1 DM)(3) | 97 | 77 | 67 | 56 |
| Rumen-undegradable protein (g Kg-1 DM)(3) | 57 | 59 | 63 | 68 |
| Metabolizable protein (g/day)(3) | 1.88 | 1.88 | 1.88 | 1.88 |
| Net energy for lactation (Mcal Kg-1 DM)(3) | 1.61 | 1.62 | 1.62 | 1.61 |
(1)Lignosulfonate-treated soybean meal (Cargill, Uberlândia, MG, Brazil). (2)Composition (kilogram of dry matter): 190 g Ca, 60 g P, 20 g S, 20 g Mg, 35 g K, 70 g Na, 15 mg Co, 700 mg Cu, 10 mg Cr, 700 mg Fe, 40 mg I, 1,600 mg Mn, 19 mg Se, 2,500 mg Zn, 200,000 IU vitamin A, 50,000 IU vitamin D3,1,500 IU vitamin E, and 600 mg F. (3)Estimated using the Cornell Net Carbohydrate and Protein System, version 6.1.