Growth and Fattening Performances of Friesian-Boran Crossbred Bull Calves Fed on Different Protein Supplements

The study was conducted at Holetta Research Center to evaluate growth performance and economic feasibility of fattening 50 and 75% Friesian-Boran growing crossbred bull calves for the period of 626 days. Twenty-four 50% Frisian-Boran crossbred weaned male calves and another twenty- four 75% Frisian-Boran crossbred growing weaned calves reared at Holetta Research Center were randomly assigned to six dietary treatments; T1=Noug seed cake based supplement with 18% CP level, T2=Noug seed cake based supplement with 20% CP level, T3= Linseed cake based supplement with 18% CP level, T4= Linseed cake based supplement with 20% CP Level, T5=Cottonseed cake based supplement with 18% CP and T6=Cottonseed cake based supplement with 20% CP Level. The interaction effect between feed supplements and calf genotypes was not significant. In this study higher (p<0.05) body weight of 196.50±7.78 and 404.88±17.96 kg was attained for 12 and 24-months growing bull calves that were supplemented with cotton seed cake at 20% crude protein level, respectively than calves supplemented with 18% CP level. Crossbred bull calves supplemented with cotton seed cake at 20% CP had also higher (p<0.05) final body weight, live weight change, daily weight gains and feed conversion efficiencies of 404.88±17.96, 334.25±17.62, 0.558±0.03 kg and 9.46±0.87 kg DMI/kg gain, respectively than those fed on noug seed cake at 18% CP level (314.25±17.96, 244.25±17.62, 0.407±0.03 kg and 13.60±0.88 DMI/kg gain), respectively. Except for initial weight, i.e., weaning weight and feed conversion efficiencies, Friesian-Boran (50% FB) crossbred growing bull calves had better (p<0.05) final body weight, live weight change and daily weight gain of 378.04±17.96, 308.79±10.17 and 0.518± 0.02, respectively compared to those with 75% exotic blood level (346.25±10.37, 275.38±10.17, and 0.463.02) respectively. Friesian Boran (50% FB) crossbred growing bull calves fed on cotton seed cake-based supplement with 20% CP level (T6) had better net income of 10792.7 ETB/head followed by those supplemented with linseed cake with 20% CP level (T4) which was 5772.6 ETB/head. Generally, dairy producers (farmers) can benefit from fattening of their crossbred dairy bull calves; especially 50% Friesian-Boran crosses using Cotton and linseed cakes-based concentrates formulated with 20% crude protein.

本研究于霍莱塔研究中心（Holetta Research Center）开展，旨在评估为期626天的育肥周期内，50%与75%弗里生-博兰（Friesian-Boran）杂交生长公牛犊的生长性能与经济可行性。研究选取该中心饲养的24头50%弗里生-博兰杂交断奶公犊，以及24头75%弗里生-博兰杂交断奶生长公犊，将其随机分为6组日粮处理组：T1为粗蛋白（Crude Protein, CP）水平18%的诺格籽饼（Noug seed cake）补充料，T2为粗蛋白水平20%的诺格籽饼补充料，T3为粗蛋白水平18%的亚麻籽饼（Linseed cake）补充料，T4为粗蛋白水平20%的亚麻籽饼补充料，T5为粗蛋白水平18%的棉籽饼（Cottonseed cake）补充料，T6为粗蛋白水平20%的棉籽饼补充料。饲料补充剂与犊牛基因型的交互效应未达到显著水平。本研究结果显示，饲喂20%粗蛋白水平棉籽饼补充料的12月龄与24月龄生长公牛犊，分别获得了196.50±7.78 kg与404.88±17.96 kg的更高体重（p<0.05），优于饲喂18%粗蛋白水平补充料的对应组别。饲喂20%粗蛋白棉籽饼补充料的杂交公牛犊，其终体重、活体重变化、日增重与饲料转化率分别为404.88±17.96 kg、334.25±17.62 kg、0.558±0.03 kg与9.46±0.87 kg干物质采食量/千克增重，同样显著优于饲喂18%粗蛋白诺格籽饼补充料的犊牛（对应指标分别为314.25±17.96 kg、244.25±17.62 kg、0.407±0.03 kg与13.60±0.88 kg干物质采食量/千克增重）。除初始体重（即断奶体重）与饲料转化率外，50%弗里生-博兰杂交（50% FB）生长公牛犊的终体重、活体重变化与日增重分别为378.04±17.96 kg、308.79±10.17 kg与0.518±0.02，均显著优于75%外血占比的杂交犊牛（对应指标分别为346.25±10.37 kg、275.38±10.17 kg与0.463±0.02）。饲喂20%粗蛋白棉籽饼补充料（T6组）的50%弗里生-博兰杂交生长公牛犊，其单头净收益为10792.7埃塞俄比亚比尔（ETB），位居首位；其次为饲喂20%粗蛋白亚麻籽饼补充料的T4组，单头净收益为5772.6 ETB。总体而言，养殖户可通过杂交奶公牛犊的育肥获益，尤其是采用粗蛋白含量20%的棉籽饼与亚麻籽饼浓缩饲料饲喂50%弗里生-博兰杂交犊牛的方案。