Toxic Effects of Straw

Oregon produces 70% of the world supply of cool season grass seed, including tall fescue (Lolium arundinaceum) and perennial ryegrass (L. perenne). About 225,000 ha of grass seed are currently in production in Oregon. Traditionally, the seed was harvested in June and July and the straw residue in the fields was burned during July and August. Today, the straw is harvested and used for animal feed, principally in Japan, Korea and Taiwan. In 2006, 33,000 containers of compressed straw were shipped to the Pacific Rim countries from Northwest US ports. The production of cool season grass seed is continuing to increase. Almost all the increase consists of cultivars with high endophyte (Neotyphodium spp.) infestation. As a consequence, much more endophyte-infected straw is being produced. Endophytes produce alkaloids that are advantageous to plants but deleterious to livestock when fed straw with too high a concentration of these toxins. In this chapter, the toxic effects of straw feeding and toxin threshold levels will be discussed.