Pyrolysis-gas-chromatography-mass-spectrometry for the analysis of forages and by-products

Abstract

Forages and by-products, such as stovers and hulls, are important ruminant feedstuffs. Considerable effort is expended on composition determination, including research to better understand the relationship between composition and utilization by ruminants. Most of the procedures used are empirical in nature and make such determinations difficult at best. For example, the primary procedures used to determine a forage's potential feeding value are based on fiber determinations using extractive procedures. While it is possible to chemically analyze feedstuffs in a non-empirical fashion, the analyses required are so time consuming and extensive as to be generally impractical. Pyrolysis-gas chromatography/mass spectrometry (PY-GC/MS), on the other hand, is simple to carry out and generates no waste, while being capable of simultaneously providing information on the composition of many or all of the feedstuff constituents. Research has demonstrated that PY-GC/MS can provide detailed information on constituents such as lignin, tannins, carbohydrates, etc. The information provided has been shown to be useful in determining the basis for wet chemical procedures (i.e. what exactly does a procedure determine), in differentiating subtle differences in composition between varieties of the same plant species, and in comparing the overall composition of one material to another. Finally, PY-GC/MS can be a tremendous tool for the determination of forage and by-product composition which has until now been largely ignored by animal nutritionists and forage researchers.