Dairy Cattle Nutrition Division, National Dairy Research Institute, Karnal, Haryana 132001, India.
Michigan Biotechnology Institute, 3815 Technology Blvd, Lansing 48910.
J Dairy Sci. 2018 Sep;101(9):7990-8003. doi: 10.3168/jds.2018-14584. Epub 2018 Jul 4.
The seasonal lack of availability of lush green forages can force dairy farmers in developing nations to rely on crop residues such as wheat and rice straw as the major feed source. We tested whether ammonia fiber expansion (AFEX) treatment of wheat straw would increase the energy available to Murrah buffalo and Karan-Fries cattle consuming 70% of their diet as wheat straw in India. Forty lactating animals of each species were blocked by parity and days in milk and randomly assigned to 1 of 4 treatment diets (n = 10). Treatments were a nutrient-rich diet with 0 to 20% straw (positive control; PC) and 3 high-straw diets with various levels of AFEX-treatment: (1) 70% untreated straw (no AFEX), (2) 40 to 45% untreated straw with 25 to 30% AFEX-treated straw (low AFEX), and (3) 20% untreated straw with 50% AFEX-treated straw (high AFEX). The AFEX-treated straw was pelleted. Urea was added to the no and low AFEX diets so they were isonitrogenous with the high AFEX diet. Animals were individually fed the PC diet for 14 d followed by 7 d of adaptation to treatments, full treatments for 28 to 35 d, and finally PC diets for 21 d. Compared with buffalo fed the PC diet, those fed high-straw diets consumed 29% less feed dry matter, put out 16% less milk energy, and lost 0.8 kg/d more body weight; the AFEX treatment of straw did not alter intake or milk production but greatly ameliorated the body weight loss (-1.0 kg/d for no AFEX and -0.07 kg/d for high AFEX). In Karan-Fries cattle, high-straw diets decreased dry matter intake by 39% and milk energy by 24%, and the high AFEX diet increased intake by 42% and milk energy by 18%. The AFEX treatment increased digestibilities of organic matter, dry matter, neutral detergent fiber, acid detergent fiber, and crude protein by 6 to 13 percentage points in buffalo and 5 to 10 points in cattle. In conclusion, AFEX treatment increased the digestibility and energy availability of wheat straw for lactating buffalo and cattle and has commercial potential to improve milk production and feed efficiency when high-quality forages or grains are not available.
在发展中国家，由于季节性缺乏茂盛的绿色饲料，奶农可能不得不依赖于农作物残余物，如小麦和水稻秸秆，作为主要饲料来源。我们测试了氨纤维膨胀（AFEX）处理小麦秸秆是否会增加食用 70%小麦秸秆的印度瘤牛和卡兰-弗里泽牛的可用能量。每个品种的 40 头泌乳动物按胎次和泌乳天数分为 10 个块，并随机分配到 4 种处理日粮中的 1 种（n = 10）。处理方法包括一种富含营养的日粮，其中含有 0 至 20%的秸秆（阳性对照；PC）和 3 种高秸秆日粮，其具有不同水平的 AFEX 处理：（1）70%未处理的秸秆（无 AFEX），（2）40-45%未处理的秸秆与 25-30% AFEX 处理的秸秆（低 AFEX），（3）20%未处理的秸秆与 50% AFEX 处理的秸秆（高 AFEX）。经 AFEX 处理的秸秆被制粒。未处理的低 AFEX 日粮和高 AFEX 日粮中添加了尿素，使其与高 AFEX 日粮的含氮量相同。动物先单独喂食 PC 日粮 14 天，然后适应处理日粮 7 天，再用完整的处理日粮喂养 28-35 天，最后用 PC 日粮喂养 21 天。与喂食 PC 日粮的瘤牛相比，喂食高秸秆日粮的动物减少了 29%的饲料干物质摄入量，减少了 16%的牛奶能量，体重每天减少 0.8 公斤；秸秆的 AFEX 处理并没有改变采食量或产奶量，但大大减轻了体重下降（无 AFEX 处理的体重每天减少 1.0 公斤，高 AFEX 处理的体重每天减少 0.07 公斤）。在卡兰-弗里泽牛中，高秸秆日粮使干物质摄入量减少了 39%，牛奶能量减少了 24%，而高 AFEX 日粮使摄入量增加了 42%，牛奶能量增加了 18%。AFEX 处理使瘤牛和牛的有机物、干物质、中性洗涤纤维、酸性洗涤纤维和粗蛋白的消化率提高了 6-13 个百分点，牛的消化率提高了 5-10 个百分点。总之，AFEX 处理提高了泌乳瘤牛和牛对小麦秸秆的消化率和能量利用率，当优质饲料或谷物不可用时，具有提高牛奶产量和饲料效率的商业潜力。
