title: Effects of diet energy density and milking frequency in early lactation on tumor necrosis factor-alpha responsiveness in dairy cows.
abstract: A whole blood stimulation assay (WBA) with Escherichia coli lipopolysaccharide (LPS) and an enzyme-linked immunosorbent assay (ELISA) were established to measure the production of tumor necrosis factor-alpha (TNF-alpha) in bovine plasma. The assays were used to study the effect of time around parturition, and diet energy density, and milking frequency on TNF-alpha responsiveness of dairy cows in early lactation. Forty cows were included in a 2 x 2 factorial block design. One factor was high (H) versus low (L) diet energy density and the other factor was two versus three daily milkings. Blood samples were collected in weeks -3, -1, 2, 3, 5, 9, and 13 around parturition, and investigated for the TNF-alpha production ex vivo and CD14+ monocytes. The TNF-alpha response, CD14+ monocyte number, and CD14 expression level on monocytes were significantly increased in the weeks close to parturition. However, dips of varying sizes were observed for the measured parameters in week 3 after calving. Diet and milking frequency had no effect on the TNF-alpha response ex vivo or CD14 expression level on monocytes, but cows fed diet H had significantly higher numbers of CD14+ monocytes than cows fed diet L. The WBA with LPS was a fast reliable method for repeated measurements of TNF-alpha responsiveness in cattle. Previous findings of increased TNF-alpha responses in periparturient cows were confirmed, whereas diet energy concentration and milking frequency had no effect on the TNF-alpha responsiveness in early lactation.
authors.affiliation: Department of Animal Health and Welfare, Danish Institute of Agricultural Sciences, Research Centre Foulum, P.O. Box 50, DK-8830 Tjele, Denmark. ChristineM.Rontved@agrsci.dk
authors.forename: C M
authors.initials: CM
authors.lastname: Røntved
authors.forename: J B
authors.initials: JB
authors.lastname: Andersen
authors.forename: J
authors.initials: J
authors.lastname: Dernfalk
authors.forename: K L
authors.initials: KL
authors.lastname: Ingvartsen
mesh_terms: D000821:Animal Feed; D000818:Animals; D002417:Cattle / Q000097:blood / Q000502:physiology*; D002149:Energy Intake / Q000502:physiology*; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary; D005260:Female; D005434:Flow Cytometry / Q000662:veterinary; D007774:Lactation / Q000502:physiology*; D018950:Lipopolysaccharide Receptors / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology; D008892:Milk / Q000378:metabolism*; D009752:Nutritional Status / Q000502:physiology; D011247:Pregnancy; D011897:Random Allocation; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis* / Q000378:metabolism
chemical_list: D018950:Lipopolysaccharide Receptors; D008070:Lipopolysaccharides; D014409:Tumor Necrosis Factor-alpha