The author is an extension beef specialist at North Carolina State University and the director of the Amazing Grazing Program, a pasture-based livestock educational initiative.

Tall fescue has become entrenched across the middle part of the eastern U.S., creating a region called the Tall Fescue Belt. Many farms were planted to tall fescue in the 1960s, and many of those original stands are still productive today. Unfortunately, the variety that was widely planted, Kentucky 31, is known to host a fungus called an endophyte, which produces toxins.

The incredible agronomic characteristics of tall fescue are also what can make it a wicked problem. Essentially, the toxins that are beneficial for the plant can be detrimental to livestock. There are many things you can do to alleviate toxicosis, including diluting pastures with other forage species, reducing fertilizer application rates, and clipping seedheads. The ultimate solution is to replace the toxic tall fescue with a nontoxic novel-endophyte tall fescue or some other species of forage.

Another conundrum is that some farmers see few fescue toxicosis symptoms in their livestock, while others see symptoms with high frequency. In the Northern and high-elevation areas, there are typically fewer problems than in the hotter parts of the Tall Fescue Belt. Also, the symptoms tend to be seasonal, being worst in early summer and minimal at other times of the year.

Your context will determine if you really have a problem with tall fescue or not. If you have high-performing cattle, fescue toxicosis will keep them from realizing their full potential. If you are finishing animals for local beef sales, fescue toxicosis will prolong the days to harvest and reduce meat quality. If you have great stands of tall fescue and few symptoms, then you might not have an issue.

Here are some truths — and some myths — about tall fescue.

“Tall fescue is a great grass.”

I think this one is both a myth and a truth. In the Tall Fescue Belt, there is no other species that can offer all the benefits of tall fescue. When Kentucky 31 was released, it quickly became the conservation plant of choice. It established quickly and stubbornly persisted year after year on marginal land. It was promoted as the first permanent pasture grass for the South, and it has lived up to that name.

The rise of the summer slump, fescue foot, and other symptoms in grazing cattle led to the discovery of the endophyte and its ergot alkaloid toxins. The impact of the toxins on animal performance causes me to personally downgrade Kentucky 31 tall fescue from a great grass to a fair one. Fortunately, there are many new generations of novel-endophyte tall fescue products on the market that bring tall fescue back to my great grass category.

One benefit of tall fescue is how well it works for winter grazing. Stockpiling forage into the fall and grazing after Christmas is a safe option because this is when the ergot toxin levels start to drop. Also, sugar content rises, and this drives improved palatability for livestock.

If you have novel-endophyte tall fescue, it can also be stockpiled, and our research shows it holds up as well as toxic fescue. A major benefit of novel-endophyte tall fescue is that it can be grazed at any time during fall and early winter because it does not have toxins.

“Kentucky 31 is the best because you just can’t kill it.”

This one is a myth. Across the Tall Fescue Belt, we are seeing many old stands of tall fescue thinning or disappearing. Most of this is because of heavy grazing, winter treading damage, reduced fertilization, and competition from warm-season annuals and perennials. Undermanagement along with frequent drought over the last two decades has resulted in poor stands of tall fescue where it used to dominate.

“Novel-endophyte tall fescue is too expensive to plant.”

This one is another myth. A farmer with excellent stands of Kentucky 31 tall fescue should carefully evaluate their situation before converting to a novel-endophyte variety. If a pasture needs to be renovated, one thing I can clearly recommend to livestock producers is not to plant Kentucky 31.

It may be true that Kentucky 31 could be the least expensive seed you can buy. Today, you can purchase Kentucky 31 for about $1.50 per pound, while novel-endophyte tall fescue seed will cost about $4 per pound. Assuming a planting rate of 15 pounds per acre, that is a difference of $37.50 per acre. If you run a budget and calculate the total cost of pasture renovation, it will come to at least $150 per acre in costs other than seed.

The truth is that renovation is expensive no matter what you plant. My economic calculations show that if you plant novel-endophyte tall fescue, it will pay you back in about four years. If you plant Kentucky 31 in the same situation, it will take eight years to make a return on investment. So, the statement should be, “Pasture renovation is so expensive you can’t afford to plant an inferior product like Kentucky 31.”

Once you renovate a pasture, there are a few practices that will help it prosper: fertilize it, don’t feed hay with toxic fescue seed on renovated acres, and don’t overgraze it. If you follow those principles, you can keep stands for the long run.

“If you have tolerant livestock, you can live with Kentucky 31.”

This one might be a truth, but finding those tolerant animals can be a challenge. Animals with heat tolerant genetics like Brahman cattle and breed composites do better on toxic tall fescue than English cattle breeds in hot environments; however, these animals may have other issues that limit their adaptation.

Early hair coat shedding in Angus cattle has been shown to be a critical trait for cattle on toxic fescue. Some breeds are developing expected progeny differences (EPDs) for tall fescue tolerance. This has been a slow process, though, so some level of fescue intolerance continues to be bred into cattle in the region.

The most powerful fescue tolerance trait described to date is the slick hair gene. This simple dominant mutation produces a high tolerance to heat and parasites. Recent research also shows high tolerance to the effects of ergot alkaloids. Tolerant livestock will continue to be an important consideration for tall fescue systems, but we are a long way from reliably purchasing animals with proven tolerance.

In the end, each farmer in the Tall Fescue Belt must decide how to manage their specific problems. Some with relatively tolerant animals, who live in cooler regions, or who simply lack the resources to renovate pastures may stick to the status quo. Other farmers may evaluate pastures and decide to renovate them to provide better nutrition for their animals.

Renovation is costly, so it should be strategically implemented to upgrade a forage system. For example, renovating select acres to native warm-season grasses or novel-endophyte tall fescue will help complement a base of toxic tall fescue.