Wang Xianjue, Ao Changjin, Liu Shuaiwang, Bai Chen, Zhang Fuquan, Zhang Ying, Gao Peng
College of Animal Science, Inner Mongolia Agricultural University, Hohhot 010018, China.
Anim Nutr. 2016 Jun;2(2):105-110. doi: 10.1016/j.aninu.2016.03.002. Epub 2016 Mar 18.
This experiment was conducted to investigate the effects of infusing milk precursors into the external pudic artery on rumen fermentation in lactating dairy cows. Eight multiparous Holstein cows were randomly assigned to Group A (experimental group) and Group B (control group) with 4 cows each. A 2 × 4 complex factor crossover design was used. Cows in Group A were fed corn straw as the only roughage, and cows in Group B were fed mixed roughage. The experiment was divided into two periods. In the first period, cows in Group A, received treatments: 1) a basal infusate as a control (CSC); 2) a milk fat precursor infusion including C16:0, C18:0, C18:1c9, C18:2c6, C18:3n3, acetic acid (CSF); 3) a milk protein precursor infusion including 16 amino acids (CSA); 4) the mixed infusion of milk fat and protein precursors (CSFA). And meanwhile, cows in Group B were infused the basal infusate as a control group. In the second period, the cows in both Groups A and B were crossed over, which cows in Group A were named as Group B and the cows originally in Group B were in Group A. The experimental results showed that cows in experimental group had higher ruminal pH compared with the control, and ruminal pH in CSC, CSF, CSA were significantly higher than those in their respective control group ( < 0.05). The concentration of ammonia nitrogen (NH-N) was significantly higher in CSA and CSFA compared with Group B ( < 0.05). We also observed that the infusion of mixed amino acids significantly increased the bacterial protein (BCP) content in rumen ( < 0.05) and influenced the rumen acetic acid concentration as well as the acetic to propionic ratio ( < 0.05). Milk fat precursors infusion significantly affected butyric acid concentration ( < 0.05). In addition, the content of lipopolysaccharide (LPS) in CSA was significantly higher than that in the control group ( < 0.05). It is concluded that the milk precursors infused into external pudic artery caused feedback effects on ruminal fermentation under the corn straw roughage conditions. The milk protein precursor increased the ruminal pH, the contents of BCP and acetic acid, which adjust rumen fermentation and improve milk performance.
本实验旨在研究向阴部外动脉输注乳前体物质对泌乳奶牛瘤胃发酵的影响。将8头经产荷斯坦奶牛随机分为A组（实验组）和B组（对照组），每组4头。采用2×4复合因子交叉设计。A组奶牛仅以玉米秸秆作为粗饲料，B组奶牛则饲喂混合粗饲料。实验分为两个阶段。在第一阶段，A组奶牛接受以下处理：1）基础输注液作为对照（CSC）；2）乳脂肪前体物质输注，包括C16:0、C18:0、C18:1c9、C18:2c6、C18:3n3、乙酸（CSF）；3）乳蛋白前体物质输注，包括16种氨基酸（CSA）；4）乳脂肪和蛋白前体物质混合输注（CSFA）。同时，B组奶牛输注基础输注液作为对照组。在第二阶段，A、B两组奶牛进行交叉，即A组奶牛命名为B组，原B组奶牛命名为A组。实验结果表明，与对照组相比，实验组奶牛瘤胃pH值更高，且CSC、CSF、CSA组的瘤胃pH值显著高于各自对照组（P<0.05）。与B组相比，CSA和CSFA组的氨氮（NH-N）浓度显著更高（P<0.05）。我们还观察到，混合氨基酸输注显著提高了瘤胃细菌蛋白（BCP）含量（P<0.05），并影响了瘤胃乙酸浓度以及乙酸与丙酸比例（P<0.05）。乳脂肪前体物质输注显著影响丁酸浓度（P<0.05）。此外，CSA组的脂多糖（LPS）含量显著高于对照组（P<0.05）。研究得出结论，在玉米秸秆粗饲料条件下，向阴部外动脉输注乳前体物质对瘤胃发酵产生反馈作用。乳蛋白前体物质提高了瘤胃pH值、BCP和乙酸含量，从而调节瘤胃发酵并改善产奶性能。
