1 材料与方法
1.1 试验动物
1.2 试验设计和饲粮
表1 饲粮组成及营养水平(干物质基础)Table 1 Composition and nutrient levels of diets (DM basis)% |
| 项目 Items | 组别 Groups | ||||
|---|---|---|---|---|---|
| Ⅰ | Ⅱ | Ⅲ | Ⅳ | Ⅴ | |
| 原料 Ingredients | |||||
| 玉米 Corn | 24.04 | 30.01 | 33.78 | 40.29 | 45.58 |
| 大豆油 Soybean oil | 0.55 | 1.67 | 3.00 | 4.01 | 5.21 |
| 豆粕 Soybean meal | 4.26 | 4.28 | 4.86 | 4.41 | 4.38 |
| 玉米干酒糟及其可溶物 Corn DDGS | 3.56 | 3.56 | 2.66 | 3.55 | 3.74 |
| 玉米秸秆 Corn straw | 20.00 | 20.00 | 20.00 | 20.00 | 20.00 |
| 羊草 Chinese wildrye | 43.92 | 36.76 | 31.92 | 23.89 | 17.18 |
| 小麦麸 Wheat bran | 1.02 | 1.02 | 1.02 | 1.02 | 1.02 |
| 石粉 Limestone | 0.22 | 0.27 | 0.33 | 0.40 | 0.46 |
| 碳酸氢钠 NaHCO3 | 0.90 | 0.90 | 0.90 | 0.90 | 0.90 |
| 食盐 NaCl | 0.54 | 0.54 | 0.54 | 0.54 | 0.54 |
| 预混料 Premix1) | 0.99 | 0.99 | 0.99 | 0.99 | 0.99 |
| 合计 Total | 100.00 | 100.00 | 100.00 | 100.00 | 100.00 |
| 营养水平 Nutrient levels2) | |||||
| 综合净能 NEmf/(MJ/kg) | 4.90 | 5.52 | 6.11 | 6.74 | 7.36 |
| 干物质(风干基础) DM (air-dry basis) | 87.80 | 87.55 | 87.44 | 87.15 | 86.94 |
| 粗蛋白质 CP | 10.08 | 10.18 | 10.37 | 10.77 | 10.01 |
| 中性洗涤纤维 NDF | 47.34 | 43.49 | 40.65 | 36.50 | 32.90 |
| 酸性洗涤纤维 ADF | 27.37 | 24.74 | 22.88 | 20.00 | 17.55 |
| 钙 Ca | 0.33 | 0.33 | 0.33 | 0.33 | 0.33 |
| 磷 P | 0.22 | 0.22 | 0.22 | 0.22 | 0.22 |
1)每千克预混料含有 Each kilogram of the premix contained the following:VA 1 000 000 IU,VD3 200 000 IU,VE 1 000 IU,烟酸 niacin 2 000 mg,泛酸 pantothenic acid 1 000 mg,叶酸 folic acid 50 mg,生物素 biotin 10 mg,Fe 4 000 mg,Cu 500 mg,Mn 2 000 mg,Zn 4 000 mg,Se 10 mg,I 50 mg,Co 1 mg。 2)综合净能为计算值,其余为实测值。NEmf was a calculated value, while the others were measured values. |
1.3 饲养试验
1.4 消化代谢试验
1.5 呼吸代谢试验
1.6 绝食代谢试验
1.7 检验指标及方法
1.7.1 生长性能
ADG(kg/d)=(末重-初重)/试验天数。
DMI(kg/d)=(饲喂量×饲粮样DM含量-剩料量×剩料样DM含量)/试验天数。
1.7.2 饲粮营养水平
1.7.3 能量代谢指标
消化能(DE,MJ/d)=GE摄入量-粪能;
代谢能(ME,MJ/d)=GE摄入量-粪能-尿能-甲烷能;
净能(NE,MJ/d)=GE摄入量-粪能-尿能-甲烷能-热增耗;
甲烷能(MJ/d)=CH4产生量(L/d)×39.54 /1 000;
总产热(THP,kJ/d)=16.175×O2消耗量(L/d)+5.021×CO2产生量(L/d)-2.167×CH4
产生量(L/d)-5.987×尿氮含量(g/d);
绝食产热(FHP,kJ/d)=16.175×绝食O2
消耗量(L/d)+5.021×绝食CO2产生量(L/d)-2.167×绝食CH4产生量(L/d)-5.987×绝食尿氮含量(g/d);
热增耗(MJ/d)=THP-FHP;
维持净能(NEm,MJ/d)=FHP;
GE消化率(%)=100×DE/GE摄入量;
GE代谢率(%)=100×ME/GE摄入量。
ER=a×W0.75+b×ADG。
1.8 数据统计分析
2 结果与分析
2.1 育肥期西门塔尔杂交公牛生长性能
表2 育肥期西门塔尔杂交公牛生长性能Table 2 Growth performance of Simmental hybrid bulls during fattening period |
| 项目 Items | 组别 Groups | P值 P-value | ||||
|---|---|---|---|---|---|---|
| Ⅰ | Ⅱ | Ⅲ | Ⅳ | Ⅴ | ||
| 初重 IBW/kg | 461.31±37.77 | 456.53±24.98 | 462.42±54.07 | 464.88±34.33 | 462.73±18.83 | 0.999 |
| 末重 FBW/kg | 493.50±50.73 | 489.33±11.45 | 495.77±43.77 | 498.53±33.66 | 502.27±35.04 | 0.994 |
| 平均日增重 ADG/(kg/d) | 1.07±0.44 | 1.09±0.53 | 1.11±0.36 | 1.12±0.03 | 1.32±0.58 | 0.956 |
| 干物质采食量 DMI/(kg/d) | 11.39±0.48 | 11.68±0.21 | 11.68±0.07 | 11.56±0.12 | 11.39±0.17 | 0.456 |
| 料重比 F/G | 11.61±3.65 | 12.22±4.81 | 11.53±4.69 | 10.31±0.16 | 10.08±5.02 | 0.959 |
2.2 育肥期西门塔尔杂交公牛能量代谢指标
表3 育肥期西门塔尔杂交公牛能量代谢指标Table 3 Energy metabolism indices of Simmental hybrid bulls during fattening period |
| 项目 Items | 组别 Groups | P值 P-value | ||||
|---|---|---|---|---|---|---|
| Ⅰ | Ⅱ | Ⅲ | Ⅳ | Ⅴ | ||
| GE摄入量 GE intake/(MJ/d) | 156.59±6.10 | 176.39±16.38 | 181.12±13.31 | 181.65±8.02 | 190.47±17.01 | 0.119 |
| 粪能 FE/(MJ/d) | 66.19±7.34 | 70.35±14.23 | 66.48±4.41 | 57.25±5.39 | 56.06±5.21 | 0.210 |
| 尿能 UE/(MJ/d) | 1.51±0.28 | 1.84±0.34 | 1.50±0.99 | 1.41±0.32 | 1.94±0.91 | 0.805 |
| 甲烷能 CH4-E/(MJ/d) | 10.16±0.20 | 11.19±1.25 | 11.24±0.45 | 11.42±1.54 | 12.96±4.66 | 0.681 |
| 消化能 DE/(MJ/d) | 90.40±4.60c | 106.04±2.35bc | 114.65±17.29ab | 124.40±6.63ab | 134.42±17.75a | 0.009 |
| 代谢能 ME/(MJ/d) | 78.73±4.12c | 93.01±1.17bc | 101.90±17.74ab | 111.57±5.01ab | 119.52±13.48a | 0.006 |
| GE消化率 GE digestibility/% | 57.80±3.47c | 60.37±4.45c | 63.07±5.21bc | 68.47±2.42ab | 70.50±0.92a | 0.007 |
| GE代谢率 GE metabolizability/% | 50.33±3.16b | 53.00±4.36b | 55.97±5.96ab | 61.43±1.50a | 62.80±1.35a | 0.009 |
| 维持净能 NEm/(MJ/d) | 50.40±2.00 | 50.67±2.34 | 50.73±3.63 | 51.47±3.30 | 51.89±1.67 | 0.954 |
| 净能 NE/(MJ/d) | 61.99±14.96c | 71.23±4.19bc | 76.64±12.27abc | 84.38±2.63ab | 93.30±11.00a | 0.031 |
2.3 育肥期西门塔尔杂交公牛能量需要量
表4 育肥期西门塔尔杂交公牛能量需要量Table 4 Energy requirements of Simmental hybrid bulls during the fattening period |
| 模型 Models | 决定系数 R2 | F值 F-value | 样本量 Sample size | P值 P-value |
|---|---|---|---|---|
| DE=0.811W0.75+25.786ADG | 0.983 8 | 398.12 | 15 | 0.003 |
| ME=0.713W0.75+23.254ADG | 0.981 0 | 385.67 | 15 | <0.001 |
| NE=0.494W0.75+22.493ADG | 0.993 6 | 379.36 | 15 | <0.001 |
DE:消化能 digestible energy;ME:代谢能 metabolizable energy;NE:净能 net energy;W0.75:代谢体重 metabolic body weight;ADG:平均日增重 average daily gain。 |
