Endophytes in Perennial Ryegrass and Tall Fescue Straw (Nutrition Update, Volume 11)

The use of turf-type perennial ryegrass and tall fescue as livestock feed can result in health problems. The presence of endophytes is beneficial to the plants but feeding straw, screenings or grazing infected pastures is known to cause fescue foot (fescue toxicosis) and ryegrass staggers in cattle, sheep and horses. Turf-type varieties can contain high levels of two alkaloids - ergovaline (in tall fescues) and lolitrem B (perennial ryegrass). Safe feeding levels of the two toxins are shown below and have been determined through work at Oregon State University. The Oregon State University testing lab is one of very few places that analyzes for these toxins.

Ergovaline (parts per billion)

Lolitrem B (parts per billion)
Horses 300 - 500 Not determined
Cattle 400 - 750 1800 - 2000
Sheep 800 - 1200 1800 - 2000

Testing of straw, straw and chaff, and chaff was done by Manitoba Agriculture and Food in 2000.  Results of a limited number of tall fescues showed ergovaline levels less than 20 ppb.  Lolitrem B levels in tall fescue exceeded 2000 ppb in 8 of the 10 samples analyzed.

For additional general information, as well as feeding recommendations, please refer to the MAFRD factsheet entitled "Endophytes in Perennial Ryegrass and Tall Fescue Straw."

February 2001