Availability and Metabolism of Various Substrates in Ruminants. I. Absorption and Metabolism of Acetate

Abstract

Two experiments were conducted in which K-acetate-1-C14 was either injected or infused intravenously into a mature dairy steer to obtain measurements of pool size, turnover rate, and turnover time of blood acetate. Estimates were made of the amount of acetate absorbed and metabolized to CO2 following feeding. It was shown that a single injection of K-acetate-1-C14 is not applicable to the measurement of acetate pool size or turnover rate because of its apparent rapid metabolism before complete mixing with the unlabeled acetate in the pool is effected. However, the turnover time of the acetate pool was calculated to be 83 min. The amount of acetate entering the pool after the consumption of 4.3 lb. of gram was estimated to be 67.24 g/hr. Of this amount, 50% was oxidized to CO2 and 50% w8 metabolized via other routes. The acetate oxidized accounted for 50% of the expired CO2.