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

Abstract

Biological fluids were analyzed for volatile constituents following a test meal of silage-grain, bromegrass pasture, hay and grain. Gas-liquid chromatographic (GLC) peak heights of the volatile materials observed were plotted as a function of feeding time. Several volatile materials increased after cows consumed the test meal. Methyl sulfide, acetone and butanone occurred and increased during the 1st hr after silage was fed. It reached a maximum concentration in about 4.5 hr. Ethanol reached an early maximum during the 1st and a secondary maximum at about 4.5 hr. Bromegrass pasture resulted in a small amount of methyl sulfide and a slight increase in acetone in milk and blood. The maximum occurred at about 4.5 hr. after feeding. Acetone, butanone, methyl sulfide and an unidentified volatile material were produced in the fluids of cows after they had consumed alfalfa hay and grain. All animals that were fasted after the test meal produced high levels of acetone in body fluids at 30 hr.