Gas Chromatographic Determination of Volatile Fatty Acids in Aqueous Media its use in Bovine Rumen Fluid and in Silage

A rapid quantitative method for the gas chromatographic determination of volatile fatty acids in aqueous media is described. It includes the use of formic acid for the elimination of “ghost peaks” and of iso-valeric acid as an internal standard. The method has been used for the examination of bovine rumen fluid and of silage.Statistical treatment of the result shows that the fluid from lactating cows has a significantly higher content of butyric acid than has the fluid from dry cows; such a difference could not be demonstrated as to acetic, propionic and valeric acid.Some experience from the determination of the volatile fatty acids in silage is also reported.