HOUSTON, Mo. — Kentucky-31 tall fescue pastures are naturally infected with a fungus (called “the endophyte”) that grows between the cell walls of the plant. The fungus produces several alkaloids that allow the plant to survive drought, insects, and grazing pressure. However, one group of alkaloids, ergot alkaloids, impact livestock performance.

“Livestock that consume toxic, endophyte-infected tall fescue experience decreased conception rates, milk production, and feed intake. This decrease in livestock performance can cost livestock producers thousands of dollars annually,” said Sarah Kenyon, agronomy specialist, University of Missouri Extension.

According to Kenyon, one management strategy is to select tall fescue cultivars that do not contain an endophyte or endophyte-free tall fescue. However, removing the endophyte also eliminates the plants ability to survive drought and insect pressure.

“The endophyte produces other alkaloids that allow the plant to survive in adverse conditions. Because of this, endophyte-free tall fescue varieties should not be planted south of the Missouri River,” said Kenyon.

FRIENDLY CULTIVARS

A better option, according to Kenyon, is to select tall fescue cultivars with non-toxic endophyte types. These cultivars of tall fescue are also called novel or friendly tall fescue.

“Non-toxic tall fescue contains endophyte strains that allow for stand persistence during drought and insects, but do not produce ergot alkaloids that result in reduced animal performance,” said Kenyon.

Several cultivars are available today, these include Jesup tall fescue with the endophyte MaxQ, Bar-Optima with E34, Texoma with MaxQII, Estancia with ArkShield, and Martin with Protek.

“Animal performance on non-toxic fescue is better than that of toxic tall fescue. Average daily gain of steers grazing non-toxic tall fescue is an average of 0.5 lb per day more than animals on toxic Kentucky-31. Conception rates and animal intake are also higher than that of animals grazing toxic tall fescue,” said Kenyon.

PASTURE RENOVATION

According to Kenyon, stand persistence can be as good as Kentucky-31. The key to good stand persistence is to renovate the old Kentucky-31 stand properly. To do this, Kenyon recommends using the spray-smother-spray method.

Spray with glyphosate, plant a smother crop, and then spray with glyphosate again before planting non-toxic tall fescue. In some situations, this process will need to be repeated to kill Kentucky-31 tall fescue completely.

“Once the new stand on non-toxic tall fescue has been established, producers will need to follow rotational grazing practices to maintain a vigorous stand,” said Kenyon.

For more information, University of Missouri Extension and NRCS support programs with the Alliance of Grassland Renewal. A list of upcoming programs can be found online at http://grasslandrenewal.org/education.htm.

Source: David Burton, University of Missouri