Supplementation with fat-coated rumen-protected glucose during the transition period enhances milk production and influences blood biochemical parameters of liver function and inflammation in dairy cows

Abstract Supplementation of rumen-protected glucose (RPG) may be a useful dietary strategy to improve energy balance in transition dairy cows. The present study was performed to investigate whether supplementation with RPG could improve milk production and reduce inflammation or infection during the transition period in cows. Twelve Holstein cows (age, 4–5 yrs; bodyweight, 515 ± 42 kg; milk yield, 16.1 ± 3.7 kg/d)in late gestation were allotted to one of 2 treatments. The treatments were a basal diet plus 200 g/d of RPG (450 g/kg of glucose, 450 g/kg of coating fat and 100 g/kg of water) or a basal diet plus 90 g/d of coating fat (CON). Treatments were applied from 1 wk before to 2 wk after calving. Animal performance data were recorded, and the overall tract apparent digestibility of prepartum or postpartum cows was determined. Blood was sampled on d −4, 0, 7, and 14 to examine the plasma biochemical parameters and proinflammatory cytokines. The RPG supplementation increased the milk yield, but did not change the dry matter intake. Compared with cows in the CON group, the plasma total protein concentration was lower in the RPG group. Cows in the RPG group had greater plasma albumin concentrations but lower globulin and interleukin-8 concentrations during the transition period. The RPG supplementation tended to increase the plasma alanine aminotransferase concentration but did not change the plasma aspartate aminotransferase concentration. Dietary RPG supplementation increased the non-esterified fatty acid concentration and tended to decrease the plasma glucose concentration. In conclusion, these results indicate that supplementation with 200 g RPG per day improves milk production and reduces inflammatory markers but might have compromised the liver function of the transition cows in this study.