What’s Wrong with Tall Fescue Grass?

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by iStockphoto.com/MrInc
Most tall fescue is infected with a fungus living within the plant, which is referred to as an endophyte.

A year before I bought my first two Black Angus calves, I purchased a 50-pound sack of tall fescue seed to sow in my 4-acre pasture. As I tossed the seed onto the thin spots of the field, I enjoyed that sense of satisfaction you get knowing you are taking care of your land. As I later discovered, I couldn’t have been more wrong.

A year after grazing the calves on the pasture, they didn’t look quite right to me. They had good appetites and seemed content, but their coats looked ragged and rust colored. Being inexperienced at the time, I thought it possible they might not be pure Black Angus, which would account for the inconsistencies. I wasn’t quite sure what to think until I did a little research into why my cattle weren’t behaving as expected.

Finding the culprit

As it turns out, tall fescue – or rather the endophytic fungus that it harbors – affects cattle, horses and other grazing animals in a variety of ways, and sometimes it can be dangerous. I was lucky, as my cattle were fine, and my family eventually enjoyed a freezer full of homegrown, grassfed beef. But it could have been worse.

Horse eating green grass.

I live in Missouri, which is part of the tall fescue belt, an area extending from North and South Carolina to eastern Kansas. Tall fescue isn’t limited to this part of the United States, though. It grows like a weed in almost every state. In fact, it is sometimes considered a weed, invading natural areas in at least 16 states. About 35 million acres of pasture are filled with tall fescue, making it the most important cultivated grass in the United States. You’ve probably stepped on it in lawns, sports fields and parks.

If unmowed, tall fescue can grow very tall – up to 4 or more feet. It can be identified by its clumpy appearance and its coarse blades, which uncurl from their base. A cheap and easy-to-grow perennial, it stays green most of the year.

Since the 1940s when the Kentucky 31 variety was introduced, it has gained a reputation for its strength and durability. “It holds a lot of hillsides together. It’s tremendous for soil conservation; it’ll grow over a wide range of soil and climate conditions, and it can tolerate overgrazing,” says Garry Lacefield, an extension forage specialist at the University of Kentucky.

Despite its long history as reliable forage for farm animals, tall fescue has an ugly, dark side. Most tall fescue is infected with a fungus living within the plant, which is referred to as an endophyte. This fungal endophyte – Neotyphodium coenophialum – contributes to tall fescue’s environmental tenacity, and also makes tall fescue toxic to animals that eat it. How bad is it? “Tall fescue is costing beef cattle producers in excess of $1 billion a year,” Lacefield says.

How it affects animals

Farm animals don’t eat a mouthful of tall fescue and then fall down and die. In fact, some tolerate it quite well and live long, healthy lives grazing it daily. Tall fescue affects different species, different breeds and even individual animals in different ways. Cattle, horses, sheep and goats all can be affected in some way by the toxins the endyophyte produces.

Cows in the barnyard.

Common problems the toxin causes include longer gestation periods, reduced number of births and poor survival of offspring. It can narrow blood vessels, making it more difficult for blood to get to an animal’s extremities. Affected cattle might have ragged, unkempt coats that are shed long after winter has passed, similar to my two Black Angus calves. Because toxic tall fescue can interfere with their ability to regulate body heat, cattle may pant a lot on hot days, and you might notice them trying to cool off by standing in ponds and creeks. They may lose their appetites, gain little weight or even lose pounds during the summer. Poor circulation can also lead to more obvious problems, including freezing ears or tails that fall off in winter.

One of the most severe problems fescue can cause in cattle is called “fescue foot,” a lameness that may start with slight difficulty walking and end up with gangrene in the hooves and rear legs.

“If you see them starting to get sore, you’ve definitely got to get them off that pasture,” says veterinarian Jason Cater of Drew County, Arkansas. “If it goes on long enough and if it’s severe enough and untreated, they’ll slough off that hoof wall, and it can be a situation where you have to put the animal down.”

Sheep can also get fescue foot, but among farm animals, horses are the most sensitive to toxic tall fescue. “Horses are affected more seriously,” Cater says. “When horses are carrying a foal, if they’re on tall fescue they develop an inflammation of the placenta that can be so severe they will sometimes abort. It also produces a lack of milk production in horses.”

What causes some animals to be barely affected while others get serious complications? Part of the explanation is the amount of toxin they eat. Some fields have less toxic tall fescue than others. On average, experts estimate that around 80 percent of all tall fescue is infected with the toxic fungus.

“If you have tall fescue on your property, you can assume it’s toxic,” says Lacefield, but the level of infection varies. A field of tall fescue that includes a mixture of clover, orchard grass or other grasses will be less toxic than one with only fescue. And some animals are stronger to begin with and are better able to tolerate the toxin.

The toxin wasn’t identified until the 1970s when Charles Bacon, then a graduate student, thought to look for a fungus associated with the grass. “We identified it, and, of course, no one would believe me at first,” says Bacon, who continues to study fungi and tall fescue with the Agricultural Research Services of the USDA. “It was as much of a problem convincing the farmers as the animal scientists. They thought all animals on fescue looked like this, and they had no idea (the animals) could be better.”

The fungus that Bacon discovered lives in the space between the plant cells on tall fescue. When the grass starts to make a seed head, the fungus moves up the stem and concentrates in the seed. The only way the fungus spreads is through those infected seeds. If a plant isn’t infected, it never will be. Unfortunately, the fungus gives the infected grass an advantage over uninfected tall fescue, and over time, the infected grass will take over a field, out-competing any other grass nearby. If nature were allowed to run its course, we could find ourselves in a future full of more and more toxic tall fescue along with more problems for the animals that eat it.

It’s not just the farm animals that are affected by tall fescue. David Long, a wildlife biologist for the Arkansas Game and Fish Commission, drives a state truck sporting a bumper sticker that reads, “Don’t Do Fescue.” He and other wildlife biologists who work for the commission use the bumper stickers to start a conversation with landowners. He wants landowners to be aware that a thick monoculture of this sod-forming grass is contributing to the loss of quail and grassland songbirds.

“Tall fescue is neither food nor cover for wildlife,” he says. Making a note that deer and turkey will cross a field of tall fescue and only eat the clover or other grasses, he says, “Landowners in a rural setting may not want to plant it in their yards if they want to observe wildlife.”

Managing tall fescue

Luckily, there’s a strong incentive for getting rid of toxic tall fescue: money. The payoff for farmers comes in the form of healthier cattle that produce more offspring. Without a steady diet of toxins, the cattle also gain weight quicker on the same amount of pasture. The Alliance for Grassland Renewal – a group composed of extension agents, researchers, cattle producers and seed companies – is promoting the use of a new type of nontoxic tall fescue to replace the toxic variety. The new variety, called “novel endophyte tall fescue,” was created by infecting tall fescue with a naturally occurring nontoxic fungus. This new variety seems as sturdy as the toxic variety but causes no problems for the animals that eat it. Its drawbacks are its cost – about two to three times more than the toxic seed – and the work involved in renovating a pasture.

Will McClain, a University of Missouri extension agent and member of the Alliance, presents workshops to Missouri farmers about the benefits and costs of switching to the novel nontoxic fescue. “Not everybody will jump on this bandwagon,” he says. “A lot of the little guys aren’t going to do this for a while. But the big producers are starting to do this.”

Replacing toxic tall fescue with the novel nontoxic variety takes some planning and commitment. It also takes an investment of time, work and money.

“It’s the same process you’d use to put in alfalfa,” McClain says. It involves killing the fescue with repeated tillage or spraying with an herbicide, planting a cover crop, then tilling or spraying again, then finally planting the novel nontoxic tall fescue.

Darrel Franson, who raises cattle near Mount Vernon, Missouri, has planted the novel nontoxic variety since 2001. By systematically replacing the infected tall fescue in some of his pastures each year, he has now renovated about 100 acres. His detailed records show exactly how much he has saved. Taking into account the improvement in birthrate and weight of calves, he has paid back the cost of renovating a pasture in two years. As for profits, he makes an additional $196 per cow per year.

“Part of the reason I can pay for renovation so quickly is that I support a cow and her calf through gestation and on through lactation on only 1.6 acres,” he says.

Other farmers, such as Chris Boeckmann in Loose Creek, Missouri, have learned to manage their tall fescue fields and aren’t comfortable making a switch to the novel nontoxic grass. Boeckmann raises about 75 steers each year, grass-feeding them mostly tall fescue. His cattle graze on his pastures from the time they have been weaned until he trucks them to the local processor. “I fully understand that the toxicity of fescue is a challenge, but that challenge can definitely be minimized,” Boeckmann says.

“One of my main focuses on fescue is trying to manage it by grazing,” he says. “We do rotational grazing, and I try to move the cows every couple of days.”

To reduce the amount of toxins his cattle are exposed to, he uses proven techniques, such as diluting his fields by planting plenty of clover, then planting annual warm-season grasses when the fescue goes dormant in the summer heat. In addition to careful management of his pastures, he has switched to South Poll cattle, a breed that does better on his pastures than the Black Angus he started with.

Whatever Boeckmann has done has worked for him. His attention to his cattle and pastures rewards him with a successful business and healthy cattle.

There’s no one-size-fits-all solution for dealing with toxic tall fescue. If your goal is to make your lawn or fields more bird and wildlife friendly, diluting tall fescue with clover and other grasses should do just that. If you’re raising farm animals, you have a range of options to try. Whatever steps you take to reduce the effects of the toxin, you’ll be making things better for yourself, your farm animals and the wildlife.

Jack Wax lives in Columbia, Missouri, where he cares for a flock of 23 chickens that roam freely on the 10 acres surrounding his home.