Effects of infusing milk precursors into the artery on rumen fermentation in lactating cows

Abstract

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 (P < 0.05). The concentration of ammonia nitrogen (NH3–N) was significantly higher in CSA and CSFA compared with Group B (P < 0.05). We also observed that the infusion of mixed amino acids significantly increased the bacterial protein (BCP) content in rumen (P < 0.05) and influenced the rumen acetic acid concentration as well as the acetic to propionic ratio (P < 0.05). Milk fat precursors infusion significantly affected butyric acid concentration (P < 0.05). In addition, the content of lipopolysaccharide (LPS) in CSA was significantly higher than that in the control group (P < 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.

Drinking Heated Water Improves Performance via Increasing Nutrient Digestibility and Ruminal Fermentation Function in Yak Calves

“…These results are inconsistent with the increased values of serum protein and VFAs in the HW group. A few reports have found that ruminal pH is essential to the digestibility of ADF and NDF [ 26 , 27 ]. Therefore, the rumen fluid pH, which was not significantly different in this experiment, might be the reason for the lack of difference in the digestibility of ADF and NDF.…”

Dietary forage to concentrate ratios impact on yak ruminal microbiota and metabolites

“…The synthesis of rumen microbial proteins is directly related to nitrogen metabolism in the rumen ( Li et al, 2019 ). Appropriate energy and protein levels in the rumen are more conducive to the growth and reproduction of rumen microorganisms and increase the utilization of feed protein by microorganisms ( Wang et al, 2016 ). In the arginine and proline metabolism pathway, arginine is degraded by arginase to ornithine, which is metabolized to produce γ -aminobuytric acid (GABA).…”

Identification of the Potential Role of the Rumen Microbiome in Milk Protein and Fat Synthesis in Dairy Cows Using Metagenomic Sequencing

“…The differential Prevotella content can alter the carbohydrate, energy, lipid, and amino acid metabolism, causing an increase in acetate, butyrate, and propionate in the HPF group. Acetate and butyrate are milk fat precursors, while propionate is the precursor of milk protein [ 63 , 64 ]. The HPF group microbiome can effectively digest the feed ingredients to degrade them into pyruvate, finally generating more VFA.…”