Fescues have long been known for longevity, hardiness, drought tolerance and high yields, according to Matt Poore, extension livestock commodity coordinator and extension ruminant nutrition specialist at North Carolina State University.

It is able to withstand heavy grazing and is excellent for stockpiling.

Fescue was introduced in the early 1940s, and early on it was known as a “wonder grass” in many regions. It was not known then that the very thing which makes fescue have many of its positive traits is what also causes severe health and reproduction problems and reduced growth in the livestock that consume it.

Fescue toxicity is a term many graziers know about, but they may not realize the importance of it or what the origin of the problem is.

The toxicity is caused by a fungus (a type of endophyte) in a symbiotic relationship with the plant. It does not harm the plant in this case, but in fescue it does harm the animals eating it. This endophyte was not identified until the 1970s, and by then millions of acres had been planted.

“The fungus that lives between the plant cells produces toxins known as ‘ergot alkaloids’ that cause severe health and reproduction problems and reduced growth in livestock,” says Poore.

Effects of the toxins include decreased milk production, poor body condition, general poor health, decreased weight gain, delayed hair coat shedding, low conception rate, low birthweight, circulatory problems (such as ear tips freezing and sloughing off of tail switches), reduced feed intake and lameness.

How bad is the problem? “All said and done, fescue is now estimated to cost the beef industry more than $1 billion a year,” Poore says.

Shipping fever (bovine respiratory disease or BRD) also costs the beef industry more than $1 billion a year, but BRD is considered by most to be a much more important problem than fescue toxicity.

“I think it is because the losses from fescue come as money that never gets into your pocket. Your cows may ‘tolerate’ fescue and still give you a 500-pound calf, and your breeding rate might be 85 percent, and your incidence of weak calves, no milk, etc., may only cost you a few calves a year.

The truth is that those calves could weigh 600 pounds, your breeding rate could be more than 90 percent, and you should have almost no losses due to weak calves or lack of milk. The difference between the fescue problems and BRD is the lost value, which is something you really don’t realize you lost.

With BRD, a feedlot owner is looking down at a dead calf that they paid $1,000 for, and it is real obvious to them that the value of that calf was a cash loss.”

Fescue is so aggressive and successful that it now covers more than 35 million acres in the eastern U.S. Poore says droughts in recent years have increased the dominance of fescue in many regions and increased the fungal infection rate of individual plants in a pasture, which increases the toxin levels. The warming climate has also resulted in fescue moving up to higher elevations.

Management of a fescue field can be a simple part of the solution, including keeping cattle off infected fescue during hot weather. Poore says, “Animals don’t tolerate the toxins well during hot weather. They do better in cool weather, and resting fescue during heat while grazing warm-season forages instead is good for the whole system.”

Poore says one great way to reduce the amount of toxicity is to limit the amount of seedhead development. “Seedheads are one of the best sources of those toxins.

Seedheads are also low in nutritive value, often being below the requirements of a lactating cow, so they really don’t do you much good,” he says.

Poore continues, “The key to limiting problems from these seedheads is to not allow them to develop, or at least to limit their development. The flowering tillers that produce seedheads are predetermined by spring and, once they are removed, no more flowering tillers will develop until the next year.

Methods of removing the seedheads are through hay production, early grazing, clipping or through chemical seedhead suppression.”

Cutting fescue for hay results in forage useful for winter feeding, and some of the toxins degrade during the curing process. Haylage can also help utilize early cutting, but toxins may be conserved in haylage systems.

Clipping seedheads helps reduce toxin loads on cows, but you need to be aware that it is an expensive and wasteful process to clip a lot of forage you paid to grow but didn’t need for the cows, Poore says. Reducing fertilization (limiting added nitrogen to only in the fall) will help limit spring seedhead production and will also increase clover stands, assuming soil pH is adequate.

“One of the best practices you can do is to turn out a little earlier than usual and move cows rapidly through the pastures during the early spring growth phases,” Poore says. “The trick is not to graze too short (leave 4 to 6 inches), but rather to move cows quickly and let them eat the boot-stage seedheads.

At that point, the seedheads are not very toxic and they are very palatable to the cows. Grazing the seedheads early will allow very significant vegetative regrowth and will result in much better-quality forage going in to late spring and early summer.”

Poore said the use of metsulfuron (an herbicide) can also be useful to suppress fescue seedheads. “There are several commercial herbicides containing metsulfuron, but there is some recent research with Chaparral (which is a combination of metsulfuron and aminopyralid) that shows it does a good job suppressing seedheads and also controls a lot of common weeds including horse nettle, pigweed and many other problem weeds,” he says.

A 2-ounce-per-acre application of Chaparral in the boot stage is the recommended practice, Poore says. He noted that if Chaparral application rate is too high, it can be pretty toxic to fescue, so overapplication should be avoided.

“Also, this practice seems to work best when there are other desirable forages such as bluegrass, orchardgrass and dallisgrass mixed in the stands which are released when fescue is suppressed,” he says.

Poore says that however it is approached, spending time early in the season controlling seedhead development (except in hayfields) will pay off later in the grazing season.

“We are working hard both in research and outreach programs to explore diversifying with alternative forages including non-toxic fescue, annuals and native warm-season grasses, and that diversification of the forage system is a great thing to do.”

Sometimes the best solution may be to kill off the fescue and replace it with warm-season grasses and non-toxic infected fescues (novel endophyte varieties).

“The real solution to this problem will be a combination of replacing toxic fescue with other forages on some acreage, improving genetic tolerance to toxic fescue in the cattle and providing supplements and/or remedies that will help alleviate symptoms of the toxins,” Poore says.  

PHOTO 1: Methods of removing fescue seedheads consist of hay production, early grazing, clipping or chemical seedhead suppression.

PHOTO 2: One real solution to the fescue problem involves replacing toxic fescue with other forages on some acreage, thus minimizing the toxicity. Photos by Matt Poore.

Kelli Boylen is a freelance writer based in Iowa.