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Forage Focus: Tall Fescue

grazing endophyte-infested fescue

Tall fescue is one of North America's most abundant forage species. It's been planted on an estimated 40 million acres from the lower Midwest to eastern Oklahoma and central Georgia. While tall fescue has some desirable agronomic traits, there are problems associated with grazing it due to the presence of an endophytic fungus that lives within the plant.

Endophyte toxicosis causes cow reproduction problems, low weaning weights, and poor gains of grazing stocker animals. Tail switches and hooves can develop a gangrenous condition and fall off, and animals often have scruffy hair coats.

Plant breeders began to work on the endophyte fungus problem, and by the mid 1980s developed tall fescue varieties with low levels of the fungus within the plant. But, was discovered that these varieties didn't persist as well as the old endophyte varieties.

More recently, plant breeders shifted to developing endophyte-infected tall fescue with a non-toxic endophyte. The aim was to obtain the improved animal performance of non-endophyte varieties, while maintaining the toughness and stand persistence of high-endophyte varieties.

Researchers at Ag Research Grasslands, Palmerstown North, New Zealand, identified a group of non-toxic (novel) endophyte strains and inserted them into elite cultivars of fescue. Under an agreement with Pennington Seed Co., Joe Bouton at the University of Georgia and New Zealander Gary Latch inserted this non-toxic endophyte technology into endophyte-free tall fescue varieties.

The result from Pennington Seed was MaxQ™. Meanwhile, the MaxQ technology has been inserted into the Jesup variety of tall fescue. Subsequent Georgia research found that beef steers grazing on Jesup MaxQ from April to June in 1999 had average gains of 2.6 lbs./day as compared to 1.7 lbs./day on high endophyte-infected Jesup.

Questioning the new cultivars
As far as MaxQ technology is concerned, several things need to be considered. First, how well will Jesup MaxQ persist throughout the Southeast. Persistence has been extensively tested both on producer farms and in research plots throughout Central and North Georgia.

"MaxQ has persisted in common Bermudagrass stands for more than six years, even when subject to constant, heavy grazing through multiple drought years," says John Andrae, Extension Forage Specialist at the University of Georgia. "I am confident that it will persist in the tall fescue belt when reasonably managed."

Several research stations within the Louisiana State University AgCenter system and in Mississippi are currently investigating Jesup MaxQ persistence. Mississippi researchers in Starkville have continuously grazed paddocks of Jesup MaxQ since 2000 and find they persist as well as the toxic variety.

Louisiana researchers are advising producers to hold off planting the new variety until more research has been conducted in Louisiana. Research is also under way at other sources to develop additional non-toxic endophyte cultivars.

ArkPlus is one relatively new tall fescue variety on the market. The University of Arkansas (UA) released ArkPlus in 2003. It's a variety developed from an endophyte-free fescue strain and infected with a non-toxic endophyte found in the Mediterranean region.

Developed by UA researchers using germplasm from the University of Missouri (MU), ArkPlus seems to have 90% the stand density of Kentucky-31 and the same resistance to stress.

Craig Roberts, an MU Extension forage specialist, says the tall fescue "could conservatively put 200 more lbs. on every steer than a toxic-endophyte fescue."

Whitey Hunt, Innisfail Farm, Madison, GA, bit the bullet and planted 40 acres of pasture in MaxQ in the 2001. "We now have 42 heifers on the MaxQ," Hunt says. "Come see the pasture, and you'll find the heifers feeding during the heat of the day. The cows on toxic fescue aren't grazing — they're in the mud or hunting for shade."

Hunt says there's also a tremendous difference in the appearance of the heifers grazing MaxQ. The cattle on MaxQ are slick-haired and in excellent body condition, he says. The cattle on toxic fescue are one or two body condition scores less — with longer hair.

Hank Bell, Madison, GA, says the real "proof of the pudding" for MaxQ came during the summer months when cattle without calves grazing KY31 were laying in the shade in the afternoon.

"The other cows with calves were out grazing MaxQ at the same time and appeared to be very comfortable," Bell says. "The cows on the MaxQ with nursing calves were in considerably better body condition than cows on KY31 fescue without calves."

Calculating cost
It can be costly to replace old, tall fescue pastures with these new varieties, says Curt Lacy, University of Georgia Extension livestock economist. Georgia has 800,000 to 2 million acres of tall fescue, primarily in the northern parts of the state. And, it costs about $200/acre to plant the newer, non-toxic varieties, he says.

"Cattlemen have to look at improving pastures as an investment, much like investing in a better bull or upgrading other parts of their operation," he says. Lacy figures a novel endophyte-infected fescue would pay for itself in five years.

John Waller does grazing and fescue toxicosis research in his work as a University of Tennessee animal scientist. He's been looking at the technology used to develop MaxQ for several years.

"This variety has been working quite well in some very diverse environments in Tennessee," he says. His data show animal performance has been as good as with the endophyte-free fescue. Cattle prefer to eat the MaxQ more than the endophyte-infected fescue, Waller adds. "In fact, we caution people to adjust stocking rates upward when grazing stands of MaxQ — it's that palatable."

Waller observed that producers running stocker cattle have seen a more pronounced payback with MaxQ — mostly due to improved animal performance. "Our general recommendation is that people who need to refurbish a fescue pasture should look at using this variety," he adds. "Our reluctance before was in persistence, but we're cautiously saying persistence is looking good with MaxQ."