Volatile Compounds in Blood, Milk, and Urine of Cows Fed Silage-Grain, Bromegrass Pasture, and Hay-Grain Test Meals1,2

Abstract

Two to four cows per treatment were fasted after test meals, their fluids were sampled for 28 to 54 hr, and analyzed by gas liquid chromatography. Methyl sulfide, acetone and butanone occurred and increased during the 1st hr after silage was fed and reached maximal concentrations at about 4.5 hr. Ethanol, however, reached an early maximum during the first hr and a secondary maximum at 4.5hr.The test meal of bromegrass pasture produced a small amount of methyl sulfide and an increase in acetone. They reached maxima at about 4.5hr.Acetone, butanone, and a small amount of methyl sulfide were the only components found consistently after test meals of alfalfa hay and grain, except that one of the four cows produced an unidentified material and did not produce butanone, except in urine.All animals fasted after the test meal developed high concentrations of acetone in body fluids at about 30hr.