Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada T6G 2P5.
J Dairy Sci. 2011 Jan;94(1):370-5. doi: 10.3168/jds.2010-3488.
Milk production, rumen fermentation, and whole-tract apparent nutrient digestibility in response to feeding 20% steam-rolled wheat with or without sodium bicarbonate were evaluated in 12 Holstein cows averaging 165±16 DIM. Cows were fed 1 of 2 isoenergetic and isonitrogenous diets containing either 0 or 0.75% sodium bicarbonate on a DM basis for 21 d in a crossover design. Rumen fluid samples were obtained 18 times during the last 2 d of each period, and fecal samples were collected on 12 occasions from d 18 to 21 of each period. Removal of sodium bicarbonate from the diet did not affect DMI (21.0 kg/d), yields of milk (30.8 kg/d), or milk components (1.16, 1.01, and 1.40 kg/d for fat, protein, and lactose, respectively). Whole-tract apparent digestibility of DM, CP, ADF, and NDF did not differ between the 2 treatments (75.3, 76.6, 67.2, and 63.6%, respectively). The mean rumen pH was 6.24 and was not affected by excluding sodium bicarbonate from the diet. Rumen NH3-N (12.31 mg/dL) and lactic acid (3.63 mM) concentrations were not different, whereas total volatile fatty acids concentration tended to increase when sodium bicarbonate was present in the diet (110 vs. 116 mM). However, average concentrations of the individual volatile fatty acids, as a proportion of total volatile fatty acids, were not affected by treatment. In conclusion, dairy cow diets can include up to 20% steam-rolled wheat without the need for added sodium bicarbonate as long as the diets are formulated to meet the fiber requirements of the cow.
在 12 头平均产奶天数为 165±16 的荷斯坦奶牛中，评估了饲喂 20%蒸汽压片小麦及添加或不添加碳酸氢钠对产奶性能、瘤胃发酵和全肠道表观养分消化率的影响。奶牛饲喂 2 种等能量和等氮的日粮，其中 1 种日粮基础上添加 0 或 0.75%碳酸氢钠，采用交叉设计，每个处理饲喂 21 天。在每个周期的最后 2 天，每隔 18 小时采集瘤胃液样品，在每个周期的第 18-21 天，采集 12 次粪便样品。日粮中去除碳酸氢钠对干物质采食量（21.0kg/d）、产奶量（30.8kg/d）和乳成分（脂肪、蛋白质和乳糖分别为 1.16、1.01 和 1.40kg/d）没有影响。2 种处理间干物质、粗蛋白、酸性洗涤纤维和中性洗涤纤维的全肠道表观消化率没有差异（分别为 75.3%、76.6%、67.2%和 63.6%）。瘤胃液 pH 均值为 6.24，且不受日粮中去除碳酸氢钠的影响。瘤胃氨态氮（12.31mg/dL）和乳酸（3.63mM）浓度没有差异，而添加碳酸氢钠时总挥发性脂肪酸浓度有增加的趋势（110 vs. 116mM）。然而，作为总挥发性脂肪酸的一部分，各挥发性脂肪酸的平均浓度不受处理的影响。总之，奶牛日粮中可以包含高达 20%的蒸汽压片小麦，而无需额外添加碳酸氢钠，只要日粮的纤维满足奶牛的需求。
