Department of Animal Science, The Pennsylvania State University, University Park, PA 16802.
Fabin Bros. Farms, Indiana, PA 15701.
J Dairy Sci. 2023 Sep;106(9):6198-6215. doi: 10.3168/jds.2022-22818. Epub 2023 Jul 26.
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.
本研究旨在比较膨化大豆粕（ESBM）与菜籽粕（CM）在基于等粗蛋白（CP）基础上对奶牛泌乳性能和瘤胃发酵的影响。在为期 2 周的协变量期后，将 48 头荷斯坦奶牛平均（±SD）：泌乳天数（DIM）为 146±46 天，产奶量（MY）为 43±7kg/d，随机分配到 2 种处理日粮中，进行完全随机区组设计实验，在收集实验数据前，这 2 种处理日粮分别进行了为期 2 周的适应期。适应期后，共采集了 7 周的样品和实验数据。奶牛根据胎次、DIM 和 MY 进行分组。处理日粮中含有 15.8%CM（CP 含量为 41.2%）或 13.2%ESBM（CP 含量为 48.7%），占全混合日粮干物质（DM）的 15.8%，其他饲料成分的添加量相似。CM 日粮中添加了菜籽油，而 ESBM 日粮中添加了大豆皮，以达到日粮间相似的乙醚提取物和中性洗涤纤维含量。在这两种日粮中均添加了尿素和瘤胃保护性 Met 和 Lys，以满足或超过奶牛的推荐量。从 10 头（每处理 5 头）瘤胃插管奶牛中采集全瘤胃内容物样品。在实验的最后一周，有 8 头瘤胃插管奶牛被移除，以参与另一项研究。处理组对奶牛的 DM 摄入量、产奶量或校正能量后的产奶量没有影响。除了实验第 5 周外，校正能量后的产奶量在处理组之间相似。与 CM 相比，除了实验第 3 周和第 7 周外，ESBM 组奶牛的乳脂浓度和乳脂产量更高。仅在经产奶牛中，与 CM 相比，ESBM 组奶牛的乳真蛋白产量更高。ESBM 组奶牛瘤胃总挥发性脂肪酸浓度和乙酸摩尔比例较高，CM 组奶牛丙酸和戊酸浓度较高。ESBM 组奶牛的乙酸丙酸比大于 CM 组。与 CM 日粮相比，ESBM 日粮增加了 Ile、Leu 和 Phe 的血浆浓度，但不包括必需 AA 的总和。与 CM 相比，ESBM 组奶牛的酸性洗涤纤维的全肠道表观消化率更高。在本实验中，以等 CP 基础在奶牛日粮中添加 CM 和 ESBM，导致奶牛的 DM 摄入量、产奶量和饲料效率相似。
