Responses of Lactation, Rumen Fermentation and Blood Biochemical Parameters with Increasing Dietary Inulin Supplementation in Mid-Lactation Dairy Cows

Effects of dietary supplementation of inulin in dairy cows were investigated in this study. Thirty-six mid-lactation Holstein dairy cows were randomly divided into six groups with six cows per group and offered a total mixed ration supplemented with 0 (control), 50, 150, 200, 250 and 350 g/d inulin per head, respectively. The animals were pre-fed for 2 weeks before rumen fluid, milk and blood samples were collected weekly for 3 weeks. With increasing inulin doses, milk yield (p < 0.01) and milk fat concentration (p = 0.04) were linearly increased, while milk urea nitrogen (p < 0.01) and somatic cell count (p = 0.04) were linearly decreased. Linear increases were also detected in the proportions of milk saturated fatty acids (p < 0.01) and polyunsaturated fatty acids (p = 0.04); however, milk monounsaturated fatty acids were linearly decreased (p = 0.04). The ruminal concentrations of acetate, propionate and butyrate increased, while the ruminal pH and the concentration of NH3-N reduced at a decreasing rate with increasing inulin doses (p < 0.01). Moreover, the concentrations of lactic acid (p = 0.03) and total volatile fatty acids (p < 0.01) were linearly upregulated. There were linear increases in the serum concentrations of superoxide dismutase (p = 0.02), immunoglobin G (p < 0.01), immunoglobin M (p = 0.04), interleukin-2 (p < 0.01) and interleukin-10 (p = 0.04); quadratic increases in serum total protein (p < 0.01) and albumin (p = 0.02) and linear decreases in serum total cholesterol (p = 0.02), triglyceride (p < 0.01) and malondialdehyde (p < 0.01). The results indicated that inulin increased milk production, shifted milk fatty acid profile, upregulated rumen volatile fatty acid concentration, and enhanced antioxidant and immunity function in dairy cows in a dose-dependent manner.

Automated summary

The study found that inulin supplementation in dairy cow feed increased milk production, changed milk fatty acid profiles, elevated rumen volatile fatty acid concentration, and enhanced antioxidant and immunity function in a dose-dependent manner.