不同收获期青贮玉米对奶牛瘤胃部分指标和消化率的影响

Effect of Corn Silage with different Harvest Stages on the Ruminal Parameters and Digestibility in Holstein Cows

[目的]为了科学利用全株玉米青贮饲料。[方法]通过3头装有永久性瘤胃瘘管的荷斯坦奶牛,采用3×3拉丁方试验设计,测定乳熟前期、乳熟期、蜡熟期玉米青贮组成的日粮对奶牛瘤胃pH值、NH3-N、VFA浓度和消化率的影响。[结果]发现:饲喂不同收获期玉米青贮日粮时奶牛瘤胃内pH值分别为6.89、6.73和6.79;氨氮浓度分别为33.32 mg/dl,38.87mg/dl和34.53 mg/dl;TVFA浓度平均值分别为66.60 mmol/L、66.52 mmol/L、59.06mmol/L;DM的消化率分别为55.67%、73.58%、76.69%;CP的消化率分别为52.93%、70.65%、71.85%;NDF的消化率分别为41.76%、66.51%、64.08%;ADF的消化率分别为29.47%、57.04%、54.79%。[结论]蜡熟期与乳熟期收获的玉米青贮组成日粮的主要营养成分消化率均高于乳熟前期,但3组日粮对奶牛瘤胃内环境及发酵产物的影响不显著。

To analyze the effects of corn silage harvested at different stages on the ruminal parameters, Three rumen fistulated Holstein dairy cattle were arranged in 3 × 3 Latin square design to test the diets containing corn silage harvested at premilk stage, milk stage, dough stage on ruminal pH value, ammonia nitrogen and VFA concentration and ruminal digestibility of feed in Holstein cows. The results showed that, when the diet with corn silage harvested at different stages, the ruminal pH values, Average of NH3- N concentrations were 6.89, 6.73 and 6.79, and 33.32 mg/dL, 38.87 mg/dL and 34.53 mg/dL, respectively. Means of total VFA were 66.60 mmol/L, 66.52 mmol/L and 85.86 mmol/L, respectively. Digestibility of DM and CP were 55.67%, 73.58% and 76.69% and 52.93%, 70.65% and 71.85%, respectively. Digestibility of NDF were 41.76 %, 66.51% and 64.08 % respectively, Digestibility of ADF were 29. 47%, 57.04% and 54.79% respectively. It implied that diets with corn silage harvested at different stage do not influence rumen parameters significantly and nutrient digestibility of diet with corn silage harvested at milk stage and dough stage higher than diet with corn silage harvested at premilk stage.