Endophyte fungus levels in perennial ryegrass and tall fescuse varieties grown for seed in Oregon, USA - implications for responsible grass straw use as livestock feed

Abstract

Baling of perennial ryegrass (Lolium perenne) and tall fescue (Festuca arundinacea) straw residue following seed harvest has become a common practice in Oregon's grass seed industry. In 2005, almost 670 000 tons [607 000 Mg (tonne)] of grass straw was exported to Japan and Korea for use as livestock feed. Most of the grass seed varieties grown today are turf-type, which in recent years have been developed with high levels of fungal endophyte infection. Currently, over 73% and 43% of perennial ryegrass and tall fescue varieties, respectively, are ranked as having a "High" (>61% infected) infection level. Concern for the safe use of these grass straw residues had led to their routine analysis for toxin content before shipment to consuming markets. These chemical analyses provide assurances against deleterious effects to livestock fed Oregon grass straw. Keywords: straw, endophyte-infected, perennial ryegrass, tall fescue