Abstract：
This study investigated the effects of extruded soybean meal (ESBM) in comparison with canola meal (CM) fed on an equivalent crude protein (CP) basis on lactational performance and ruminal fermentation of dairy cows. Following a 2-wk covariate period, 48 Holstein cows averaging (±SD): 146 ± 46 d in milk (DIM) and 43 ± 7 kg/d milk yield (MY) were assigned 1 of 2 treatment diets in a randomized complete block design experiment, which included a 2-wk period for dietary treatment adaptation before experimental data were collected. Following the adaptation period, samples and experimental data were collected for a total of 7 wk. Cows were blocked based on parity, DIM, and MY. Treatment diets contained 15.8% CM (containing 41.2% CP) or 13.2% ESBM (with 48.7% CP) of total mixed ration dry matter (DM), with similar inclusion of other feed ingredients. The CM diet was supplemented with canola oil, whereas the ESBM diet was supplemented with soybean hulls to achieve similar ether extract and neutral detergent fiber contents between the diets. Urea and rumen-protected Met and Lys were added to both diets to meet or exceed cow recommendations. Whole-ruminal digesta samples were collected from 10 (5 per treatment) ruminally cannulated cows. Eight cannulated cows were removed during the last week of the experiment to participate in another study. Treatment did not affect DM intake and MY or energy-corrected MY of the cows. Energy-corrected MY, apart from experimental wk 5, was similar between treatments. Apart from experimental wk 3 and 7, milk fat concentration and yield were greater for cows fed ESBM compared with CM. In multiparous cows only, milk true protein yield was greater for cows fed CM compared with ESBM. Ruminal concentration of total volatile fatty acids and the molar proportion of acetate were greater for ESBM, and propionate and valerate were greater in cows fed CM. Acetate to propionate ratio was greater for cows fed ESBM versus CM diet. Compared with the CM diet, the ESBM diet increased plasma concentrations of Ile, Leu, and Phe but not the sum of essential AA. Apparent total-tract digestibility of acid detergent fiber was greater in cows fed ESBM relative to CM. In this experiment, CM and ESBM included on an equal CP basis in the diet of dairy cows, resulted in similar DM intake, MY, and feed efficiency.
摘要：
这项研究调查了挤压豆粕（ESMM）与在同等粗蛋白（CP）基础上饲喂的油菜粉（CM）对奶牛泌乳性能和瘤胃发酵的影响。在2周的协变量周期之后，平均48头荷斯坦奶牛（±SD）：146±46d的牛奶（DIM）和43±7kg/d的产奶量（MY）在随机完整的区组设计实验中分配了2种处理饮食中的1种。其中包括在收集实验数据之前进行2周的饮食治疗适应。适应期之后,共收集了7周的样本和实验数据。奶牛是根据平价被封堵的，DIM,和我的。处理日粮含有15.8%CM（含41.2%CP）或13.2%ESMM（含48.7%CP）的总混合日粮干物质（DM），含有类似的其他饲料成分。CM饮食补充了菜籽油，而ESMM饮食中添加了大豆壳，以实现饮食之间相似的醚提取物和中性洗涤纤维含量。将尿素和瘤胃保护的Met和Lys添加到两种饮食中以满足或超过奶牛的建议。从10头(每个处理5头)日流插管的母牛中收集全瘤胃消化物样品。在实验的最后一周，将八头插管的母牛取出，以参与另一项研究。治疗不影响DM的摄入量和MY或能量校正的MY牛。能量校正我的，除了第5周的实验外，处理之间的情况相似。除了实验第3周和第7周，与CM相比，饲喂ESBM的奶牛的乳脂浓度和产量更高。仅在多胎母牛中，与ESMM相比，饲喂CM的奶牛的牛奶真蛋白产量更高。总挥发性脂肪酸的瘤胃浓度和乙酸盐的摩尔比例较大，饲喂CM的奶牛中丙酸和戊酸含量更高。与CM饮食相比，饲喂ESMM的奶牛的乙酸盐与丙酸盐的比率更高。与CM饮食相比，ESMM饮食增加了Ile的血浆浓度，Leu,和Phe，但不是基本AA的总和。相对于CM，饲喂ESBM的奶牛对酸性洗涤剂纤维的表观总道消化率更高。在这个实验中,CM和ESMM在相等的CP基础上包括在奶牛的饮食中，导致类似的DM摄入量，我的,和饲料效率。
