Volatile Constituents of Grass and Corn Silage. II. Gas-entrained Aroma

Abstract

Gas-entrained volatile constituents of silages which are available for rapid transmission to the mammary gland via the respiratory system of the cow were collected in cold traps and identified by gas-liquid chromatography. The volatiles from the grass silages examined were mixtures of methylsulfide, ethanal, propanal, acetone, butanone, methanol, ethanol, propanol, 2-butanol, methylacetate, and the ethyl and propyl esters of formic, acetic, propionic, and butyric acids. While methylsulfide, ethanal, methanol, ethanol, methylacetate, ethyl formate, and ethyl acetate were commonly detected in the corn silage volatiles, propanal, acetone, butanone, propanol, 2-butanol and other esters were not consistently detected, and the butyrates were usually absent. Inhalation of some of these compounds in the vapors over silage or in the vapors eructated from the rumen are believed to be responsible in part from the development of feed flavor in milk from cow fed silage.