Volatiles from Fresh and Air-Dried Vegetative Tissues of Tall Fescue (Festuca arundinacea Schreb.): Relationship to Cattle Preference

Volatiles from fresh and air-dried forage of eight tall fescue cultivars were collected on Tenax-TA adsorbent and then examined by gas chromatography/mass spectrometry (GC/MS) and GC/flame ionization detector chromatography (GC/FID). Fifty of 52 compounds emitted from fresh forage and 99 of 103 emitted from hay were identified. The same compounds were common to all cultivars, and quantitative differences, within fresh forage or hay, were not dramatic. Fresh forage yielded 12−32 μg/L of volatiles, while dry forage yielded 0.18−0.47 μg/L. ( Z )-3-Hexenyl acetate made up 82% of total emissions from fresh forage but only 0.24% from hay. Green-leaf odor compounds made up 11% in fresh forage and 6% in hay. Previously determined grazing preferences by cattle were related positively to 6-methyl-5-hepten-2-one and negatively to ( Z )-3-hexenyl propionate and acetic acid, which together made up <0.2% of volatiles from fresh forage.