Submitted to: American Dairy Science Association Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 7/24/2002
Publication Date: N/A
Citation: Interpretive Summary:
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 plasma concentrations of macro-minerals, vitamin D, and protein. 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 0, 2, 6, 24, and 48 h samples only. Parallel response trends were observed for all doses of LPS administered; therefore, LPS response data were combined and analyzed as either 0 ug/kg BW LPS (CTL) or all doses of LPS combined (TRT). Plasma calcium (9.52 vs. 8.57 mg/dl, SE=0.36) and phosphorus (5.81 vs. 4.26 mg/dl, SE=0.34) concentrations decreased after LPS infusion (P less than 0.05 and P less than 0.005, respectively), but differences in plasma magnesium concentrations were not significant (2.16 vs. 2.21 mg/dl, SE=0.04; P more than 0.20). Plasma 25-OH vitamin D3 (80.4 vs. 75.9 ng/ml, SE=3.5) was not different (P more than 0.20), whereas 1,25-(OH)2vitamin D3 (50.9 vs. 42.1 pg/ml, SE=3.8) tended to decrease (P=0.08) after LPS infusion. Differences in plasma protein concentration (7.72 vs. 7.55 g/dl, SE=0.10) after LPS administration approached a trend (P=0.17). These data suggest that the inflammatory response elicited by LPS alters plasma macro-mineral and vitamin D concentrations that are important for calcium homeostasis and metabolic health of lactating dairy cows.