|Waldron, M - CORNELL UNIV, NEW YORK|
|Nishida, T - CORNELL UNIV, NEW YORK|
|Overton, T - CORNELL UNIV, NEW YORK|
Submitted to: Journal of Dairy Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 4, 2003
Publication Date: November 20, 2003
Citation: Waldron, M.R., Nonnecke, B.J., Nishida, T., Horst, R.L., Overton, T.R. 2003. Effect of lipopolysaccharide infusion on serum macromineral and vitamin D concentrations in dairy cows. Journal of Dairy Science. 86(11):3440-3446. Interpretive Summary: The susceptibility of the dairy cow during late pregnancy and early lactation to infectious disease has been associated with underlying metabolic disease. As examples, recently calved cows with milk fever or retained placenta are more susceptible to mastitis, suggesting that metabolic factors compromise immunity. Numerous studies have investigated the influence of metabolism on immune function in dairy cattle; however, few studies have considered the effects of the activated immune system on metabolism. The primary objective of this study was to determine if experimentally induced immune activation would modulate mineral (i.e., calcium, phosphorus, and magnesium) levels in the blood of mid-lactation cows. A secondary objective was to examine associations between mineral and vitamin D (a hormone that regulates mineral levels in the body) concentrations in the blood of control (i.e., normal) cows and cows with activated immune systems. Results indicated that activation of the immune system induced by the infusion of a bacterial component called lipopolysaccharide caused decreased concentrations of calcium and phosphorus in the blood. Blood levels of magnesium and two forms of vitamin D, however, were unaffected by immune activation. Mechanisms responsible for the reduction in blood levels of calcium and phosphorus after immune activation are unclear and require further investigation. The decreased blood calcium and phosphorus, however, may indicate a causative mechanism whereby immune activation increases the risk of secondary metabolic disorders such as retained placenta, displaced abomasums, and milk fever. Further research regarding effects of immune activation on mineral metabolism in dairy cattle is warranted. These further research results will be of great benefit to the dairy industry worldwide.
Technical Abstract: Four multiparous lactating cows (175-220 DIM) were used in a 4X4 Latin square design to assess the effects of increasing doses (0.0, 0.5, 1.0, 1.5 ug/kg BW) of lipopolysaccharide (LPS; E. coli 0111:B4) on circulating concentrations of macro-minerals and vitamin D metabolites. Treatments were dissolved in 100 ml of sterile saline and infused intravenously over a period of 100 min. Blood was sampled immediately before infusion (0 h), at 60-min intervals for 8 h, and at 24 and 48 h postinfusion. Vitamin D metabolites were analyzed in samples collected at 0, 2, 6, 24, and 48 h only. Serum calcium and phosphorus concentrations decreased after LPS infusion, but there was no effect on serum magnesium concentration. Plasma 25-OH vitamin D3 and 1,25-(OH)2 vitamin D3 were not affected by LPS infusion; however, when analyzed as 0 versus all other doses of LPS combined, there was a tendency for plasma 1,25-(OH)2 vitamin D3 concentration to decrease when cows were infused with LPS. These data suggest that the inflammatory response elicited by LPS alters plasma macro-mineral concentrations and may have important implications for calcium homeostasis and metabolic health of lactating dairy cows.