This article originally appeared in the January 2008 Ag News and Views newsletter.
One of the major forage research emphasis areas here at the Noble Research Institute is developing perennial cool-season grass grazing systems that will take the place of annual cool-season forage systems. The hope is that perennial forage will eliminate the cost of establishing an annual winter pasture and improve margins for stocker producers. Of all the grasses that have been evaluated so far, the greatest strides have been made with tall fescue. Noble Research Institute studies looking at tall fescue production, economics of production and management are underway.
Across the nation, tall fescue covers some 35 million acres making it one of the most popular forages in the country. Unfortunately, for many people the mere mention of tall fescue brings an automatic dismissal conjuring up bad experiences with poor animal performance or lack of persistence. There are a lot of negative feelings that need to be overcome before tall fescue becomes an accepted option.
The majority of tall fescue is infected with a fungal endophyte. This fungus lives between the cells of the plant in a symbiotic relationship. The plant provides the endophyte with shelter and nutrients - a place for the fungus to live and reproduce. The endophyte returns the favor by producing alkaloid compounds that provide the plant with insect and drought resistance, grazing tolerance and overall plant persistence. Regrettably, some of the alkaloids produced by an endophyte-infected plant cause poor animal performance, including low average daily gain (ADG), rough hair coats, elevated body temperatures, etc., and are one reason producers developed a bad taste for tall fescue.
Endophyte-infected plants produce endophyte-infected seed that will produce other endophyte-infected plants. In the field, the only way that the endophyte can travel is through the seed. Researchers found that over time the endophyte can die in the seed, leaving the potential for growing an endophyte-free plant. This discovery led to the release of several endophyte-free varieties of tall fescue in the 1980s and early 1990s. These varieties were thought to be the answer to eliminating poor animal performance of livestock grazing tall fescue, and they were. Sadly, another problem arose with the elimination of the endophyte, the symbiotic relationship, along with the plant persistence qualities, was lost. While the endophyte-free varieties gave good animal performance, they tended to persist only about five years or less. This left a lot of producers happy with animal performance, but very unhappy with lost stands.
This leads to a new generation of tall fescues. New Zealand researchers isolated naturally occurring endophytes that produced alkaloids associated with insect persistence, but did not produce alkaloids associated with poor animal performance. These "animal-friendly" endophytes are termed "novel." The first commercial release of novel endophyte-infected tall fescue was the MaxQ® endophyte inserted into the tall fescue variety Jesup and released as Jesup MaxQ. In trials at the Noble Research Institute, Jesup MaxQ has shown greatly increased ADGs and better plant persistence than toxic endophyte-infected Kentucky 31+.
These new tall fescues look to be well adapted to clay-type soils east of I-35. However, west of I-35 where rainfall is lower, the selection for an adapted tall fescue becomes very important. How do we expand the range of tall fescue? A couple of options are being evaluated here at the Noble Research Institute. A selection of tall fescue was chosen by plant breeder Andy Hopkins at the Pasture Demonstration Farm west of Ardmore and infected with a novel endophyte. This selection has proven to be better adapted than Jesup MaxQ in trials in our region. It has been planted on cooperator farms and is being evaluated in production environments. Another option is tall fescues that go dormant during the summer and break dormancy in the fall. These types of tall fescues avoid summer droughts and, if production is similar to non-summer-dormant tall fescue, will further help expand the westward range of tall fescue.
These are not the tall fescues of old. They will offer exciting opportunities for grazing managers in the future.