Table 1.
Ingredients and nutritional composition of the experimental rations (DM basis).
| Item | Dietary levels of RSC, % DM |
|||
|---|---|---|---|---|
| 0 | 2.7 | 5.4 | 8.0 | |
| Ingredients, % | ||||
| Corn | 27.50 | 28.30 | 28.90 | 29.15 |
| Corn gluten meal | 5.60 | 3.73 | 2.00 | 0.10 |
| Soybean meal | 5.35 | 4.32 | 3.20 | 2.20 |
| RSC | 0.00 | 2.65 | 5.35 | 8.00 |
| Sodium chloride | 1.00 | 1.00 | 1.00 | 1.00 |
| Sodium bicarbonate | 1.00 | 1.00 | 1.00 | 1.00 |
| Premix1 | 2.00 | 2.00 | 2.00 | 2.00 |
| Corn silage | 57.55 | 57.00 | 56.55 | 56.55 |
| Total | 100.00 | 100.00 | 100.00 | 100.00 |
| Nutritional composition | ||||
| NEmf2, MJ/kg | 5.42 | 5.50 | 5.48 | 5.48 |
| OM, % | 89.52 | 89.42 | 89.41 | 89.68 |
| CP, % | 11.96 | 12.06 | 12.04 | 11.93 |
| RDP3, % CP | 64.53 | 63.52 | 61.42 | 58.18 |
| RUP3, % CP | 35.47 | 36.48 | 38.58 | 41.82 |
| ADIP, % CP | 7.85 | 8.45 | 9.11 | 10.09 |
| Neutral detergent fiber, % | 44.85 | 44.14 | 44.52 | 44.91 |
| Acid detergent fiber, % | 25.54 | 25.49 | 25.99 | 26.46 |
| Ether extract, % | 1.49 | 1.80 | 1.82 | 2.05 |
| GLS and metabolites, mmol/g | ||||
| GLS | 0.00 | 5.99 | 12.10 | 18.09 |
| SCN | 0.00 | 0.01 | 0.02 | 0.03 |
| Total | 0.00 | 6.00 | 12.12 | 18.12 |
DM = dry matter; RSC = rapeseed cake; NEmf = net energy for maintenance and fattening; OM = organic matter; CP = crude protein; RDP = rumen degradable protein; RUP = rumen undegradable protein; ADIP = acid detergent insoluble protein; GLS = glucosinolates; SCN = thiocyanate.
Provided per kilogram DM of ration: 54 mg Zn (ZnSO4); 70 mg Fe (FeSO4); 38 mg Mn (MnSO4); 12.8 mg Cu (CuSO4); 1.2 mg I (KI); 0.17 mg Se (Na2SeO3); 0.6 mg Co (CoCl2); 2.31 mg vitamin A; 75 μg vitamin D3.
NEmf was calculated according to Feng (2000).
The contents of RDP and RUP were calculated according to NRC (2001) based on the nitrogenous fractions of feeds analyzed using the methods of Licitra et al. (1996).