Effects Of Infusion With Milk Precursors Into External Pudic Artery On Rumen Fermentation In Lactating Dairy Cows

This study aims to reveal effect of different diet pattern and infusion with nutrition on rumen fermentation under the diet condition with single corn straw as roughage and mixed roughage.Experiment 1 Two kinds of different quality roughage on rumen fermentation of comparative study2×2 single factor crossover design was used and eight cows were randomly divided A and B groups with four cows each. The test had two phases with 14 days each. In first phase, cows in group A fed CS diet with corn straw as roughage and group B fed MF diet with mixed roughage; after transitional period, in the second phase, the group A fed MF diet and group B fed CS diet. We collected rumen fluid samples on the last day in each phase and analyzed the indicators of pH, NH3-N, BCP, VFA and LPS. The results showed that the pH value of MF treatment was higher than CS treatment without big gap. The NH3-N concentration in MF tended to be higher compare to CS(P=0.05). And the BCP concentration had the same tendency(P=0.07). Acetic acid in CS tended to be lower compare to MF (P=0.08), but propionic acid and butyric acid in CS had no significant difference compare to MF. The TVFA and acetic to propionic ratio were lower than MF without significant influence. However, the content of LPS was significantly higher than MF (P=0.0086)Experiment 2 Effects of infusion with milk precursors into external pudic artery on rumen fermentation in lactating dairy cowsEight multiparous Holstein cows were randomly assigned to A and B groups with four cows each.2×4 complex factors crossover design was used. Cows in the experimental group were fed corn straw as the only roughage, and cows in the control group were fed mixed roughage. The experiment was divided into two periods. In the first period, group A, as the experimental group, Conducted treatments:1) a basal infusate as control (CSC); 2) milk fat precursor infusion (CSF); 3) milk protein precursor infusion (CSA); 4) the mixed infusion of milk fat and protein precursors (CSFA). And meanwhile, group B infused basal infuscate as the control In the second period after transition, the treatments of group A and B were exchanged. The experimental results showed that cows treated with experimental treatments had higher ruminal pH compared with the control, and that in CSC, CSF, CSA were significantly higher than their respective control group (P<0.05). And fatty acid infusion group and amino acid infusion group had significant difference (P<0.05) The NH3-N concentration in CSF and CSFA were significantly higher than each control group (P<0.05). And CSC and CSF had significant difference with CSA (P<0.05). We also observed that infusion of amino acids significantly increased the BCP content in rumen (P<0.05) compared to control group. CSA tended to be higher than CSC and CSF. The acetic acid in CSA was significant higher than MFA and CSC (P<0.05). The propionic acid in CSA and CSFA were significant lower than CSC (P<0.05). In addition to the butyric acid in CSF was significant lower than MFF (P<0.05), there were no difference between the infusion groups. And the TVFA also had no difference among the infusion groups. The acetic to propionic ratio in CSA was significant higher than MFA (P<0.05) and that in CSA and CSFA were significant higher than CSC (P<0.05). In addition, the content of LPS in CSA is higher than control group significantly (P<0.05). But there were no significant difference among the infusion group. Overall, the trend of infusion group of LPS content was same as each control groups.The overall result is that the rumen fermentation indications were variance with two typical diets. Rumen microbes could use nitrogen source effectively because of the concentrations of NH3-N and BCP in mixed roughage group were significant higher than corn straw group. The effect of rumen fermentation of mixed roughage is better than single corn straw roughage. Milk precursors infused into external pudic artery caused feedback effects on ruminal fermentation under the corn straw roughage conditions. The milk protein precursor increases ruminal pH, BCP and acetic acid to adjust rumen fermentation and improve milk performance.