Glucose Metabolism in Dairy Cattle and the Effect of Acetate Infusion

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Abstract
Glucose turnover rate, glucose pool size, and glucose space were determined in 3 Holstein cows 2-4 hr after feeding, using 2 isotope dilution techniques. Turnover rates obtained by the single injection and constant infusion methods were 1.46 and 1.12 mg/min/kg body wt, respectively. The mean pool size, when expressed on a unit weight basis (mg/kg body wt), and mean turnover rate were significantly higher (P<0.05) as determined by the single injection procedure. Comparison of the ruminant turnover rate data to non-ruminant data lends further support to the contention that glucose is quantitatively less important in ruminant metabolism. Evidence of dminished glucose utilization was obtained during the intravenous infusion of unlabeled acetate (approximately 1 Mol/hr). Glucose turnover rates obtained during acetate infusion were only 75 and 79% of the preinfusion rates. These data are interpreted as suggesting the preferential utilization of acetate by the peripheral tissues during intervals of increased acetate availability.