[目的]探究日粮中添加乳糖对奶牛泌乳性能及瘤胃发酵的影响。[方法]选用胎次、体况相近的泌乳期中国荷斯坦牛20 头,随机分为4 组,分别为对照组、试验Ⅰ组、试验Ⅱ组和试验Ⅲ组,对照组饲喂基础日粮,试验Ⅰ~Ⅲ组在基础日粮中分别添加5%、10%和15%乳糖,预试验7 d,正式试验30 d。分别用乳成分分析仪、比色法和气相色谱法等测定乳成分及瘤胃发酵参数。[结果]与对照组相比,各试验组奶牛干物质采食量、产奶量和常规乳成分无显著影响（P>0.05）,但产奶量随乳糖添加量的增加呈升高趋势,乳脂、乳蛋白和乳糖含量也有提高趋势。与对照组相比,试验Ⅱ组和Ⅲ组的奶牛乳脂率显著升高（P<0.05）,试验Ⅰ组、Ⅱ组和Ⅲ组的乳糖率显著升高（P<0.05）。与对照组相比,各试验组奶牛瘤胃pH值、总挥发性脂肪酸、氨态氮浓度和脂多糖含量等指标无显著差异（P>0.05）,试验Ⅲ组奶牛瘤胃乙酸和异丁酸含量显著降低（P<0.05）,试验Ⅱ组、Ⅲ组奶牛瘤胃丁酸含量显著升高（P<0.05）。[结论]日粮中添加乳糖可改善奶牛泌乳性能,对泌乳期奶牛瘤胃发酵有促进作用。
[Objective] The aim was to explore the effect of adding lactose to diet on lactation performance and rumen fermentation of dairy cows. [Method] Twenty lactating China Holstein cows with similar parity and body condition were randomly divided into four groups, namely, control group, experiment group I, experiment group II and experiment group III. The control group was fed with basic diet, and experiment groups I-III were fed with 5%, 10% and 15% lactose on the basis of basic diet, respectively. The preliminary experiment lasted for 7 days and the formal experiment lasted for 30 days. Milk components and rumen fermentation parameters were determined by milk component analyzer, colorimetry and gas chromatography respectively. [Result] Compared with the control group, the dry matter intake, milk yield and routine milk components of dairy cows in each experimental group had no significant effect (P > 0.05), but the milk yield increased with the increase of lactose dosage, and the contents of milk fat, milk protein and lactose also increased. Compared with the control group, the milk fat rate of dairy cows in experimental group II and III increased significantly (P < 0.05), and the lactose rate in experimental group I, II and III increased significantly (P < 0.05). Compared with the control group, there were no significant differences in rumen pH, total volatile fatty acids, ammonia nitrogen concentration and lipopolysaccharide content among the experimental groups (P > 0.05). The contents of acetic acid and isobutyric acid in the rumen of the experimental group III were significantly decreased (P < 0.05), while the contents of butyric acid in the rumen of the experimental group II and III were significantly increased (P < 0.05). [Conclusion] Adding lactose to the diet can improve the lactation performance of dairy cows and promote rumen fermentation of dairy cows during lactation.
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