|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., Nishida, T., Nonnecke, B.J., Overton, T.R. 2003. Effect of lipopolysaccharide on indices of peripheral and hepatic metabolism in lactating cows. Journal of Dairy Science. 86(11):3447-3459. Interpretive Summary: Gram-negative bacteria are responsible for the pathology of many diseases of livestock. Neonatal septicemia, mastitis, certain diarrheas and pneumonias, and metritis are infections in dairy cattle commonly caused by these organisms. Because infectious disease can impact productive processes, it is important to minimize its occurrence in order to maintain profitability in livestock production systems. There is a dearth of information regarding the effects of infectious disease on the metabolism of cattle. The objective of this study was to characterize the effects of experimentally induced inflammation, also referred to as immune activation, on multiple aspects of metabolism in lactating dairy cows. Results from this study indicate that immune activation results in significant changes in productive (i.e., milk production), clinical (i.e., body temperature and feed intake), and metabolic (i.e., hormone, glucose and fat levels in the blood as well as liver function) well-being of the lactating dairy cow. In particular, the cow's capacity to metabolize energy-rich nutrients was altered dramatically, possibly benefitting the energy demands of an activated immune system. Using a similar experimental approach, we will determine if the metabolism of the recently calved cow experiencing the physiologic stress associated with calving and the induction of lactation is more severely affected by immune challenge. The results of this study will be of great benefit to the livestock industry world-wide.
Technical Abstract: Four multiparous lactating cows [175-220 days in milk (DIM)] were used in a 4x4 Latin square design to assess the effects of increasing doses [0.0, 0.5, 10, 1.5 ug/kg body weight (BW)] of lipopolysaccharide (LPS; Escherichia coli 0lll:B4) on performance and plasma metabolite and hormone concentrations. In addition, effects of immune activation on in vitro hepatic metabolic capacity were evaluated in 12 multiparous lactating cows (150-220 DIM) infused with 0 (n=6), 1.0 (n=4), or 2.0 (n=2) ug LPS/kg. Animals administered 0 ug LPS/kg BW were pair-fed with an LPS-infused animal during this portion of the study. For both objectives, LPS was dissolved in 100 ml of sterile saline and infused intravenously over a 100-min period. Milk production decreased linearly with LPS dose for 24 h after LPS infusion and generally returned to preinfusion levels by the sixth milking after LPS infusion. The DMI also decreased linearly by dose for 24 h following LPS infusion and regained preinfusion levels 3 d after infusion. Blood was sampled immediately before infusion (0 h) at 60-min intervals for 8 h, and at 24 and 48 h postinfusion. Overall mean plasma tumor necrosis factor-alpha (TNF-alpha), insulin, glucagon, and cortisol concentrations increased linearly with LPS dose and plasma beta-hydroxybutyrate (BHBA) decreased linearly by dose after LPS infusion. Infusion of LPS decreased the insulin:glucagon molar ratio, but did not affect plasma concentrations of growth hormone (GH), insulin-like growth factor-1 (IGF-1), leptin, or L-(+-) lactate. Plasma concentrations of glucose tended to increase initially and subsequently decrease, and there was a quadratic tendency for increased plasma nonesterified fatty acids (NEFA) concentrations after LPS administration. In the second objective, hepatic capacity for conversion of [1-14C]L-(+-) lactate and [1-14C]palmitate, but not [1-14C]propionate or [1-14C]L-alanine, to CO2 increased after LPS administration. Hepatic capacity to convert [1-14C]propionate to glucose tended to increase, but neither esterification nor the conversion of palmitate to acid soluble products were altered by LPS.