Wednesday, June 19, 2024
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Living With Endophyte Infected Tall Fescue

Fescue without legumesThe so-called ‘fescue belt’ has some of the highest beef cow concentrations anywhere in the US. That raises the question, if fescue is so bad, why are there so many cattle where it grows? The bottom line is fescue is only bad if you don’t know how to use it effectively. For those cattle producers who do know how to use it, having tall fescue is one of the first steps to being a low-cost cattle producer.

A quick review of the fescue problem reminds us an endophytic fungus growing inside the plant is the real cause of fescue toxicity. That toxicity includes the production of alkaloids that suppress the animal’s appetite and reduce blood flow to the body extremities. This results in heat stress in the summer and potential for gangrene in the feet and tail in cold weather. The seed heads are the most toxic part of the plant and the leaf blade is least toxic. Understanding these basic factors is the basis of learning how to manage fescue effectively.

Here are some strategies for managing fescue. There is a perception that fescue is a dominating plant that will overpower everything else in the pasture and leave you with nothing but toxic fescue. This can occur but it is the direct response of poor grazing management. Cheap nitrogen fertilizer through the 1950s and 60s along with continuous grazing is what gave fescue this reputation. Take those two factors out of your management and fescue becomes a much friendlier plant.

Appropriate level of clover for fescue dilution.
Appropriate level of clover for fescue dilution.

Implementing Management-intensive Grazing is the first step to getting in control of the fescue issue. This will do several beneficial things for you. First thing is it will allow you to increase plant diversity in the pasture. Tall fescue thrives under continuous grazing while most other plants do not. Timing and degree of impact of grazing allows other plants to compete effectively with the fescue. Species diversity allows the grazing animals to dilute the toxins in their daily diet by offering something else to eat. Remember, ‘the solution to pollution is dilution’. If you have other grasses and legumes growing in the mixture, the livestock simply consume much less of the toxins. Orchardgrass, redtop, crabgrass, perennial warm-season grasses, and a wide range of legumes are all suitable companion plants for infected fescue.

Alkaloids are nitrogen-containing compounds. The more available N, the higher the alkaloid level and the more toxic the fescue becomes. Putting on a big slug of N fertilizer spikes the toxicity of fescue. Using legumes in the pasture mix to supply a lower, slow release N availability can help reduce toxicity levels. Obviously the legume component also contributes to diluting the diet itself as well.

DSCN0147With seed heads being the most toxic part of the plant, we can avoid seed head production with aggressive Spring grazing. Fescue will only produce a seed head on the first growth flush of the year. Timing and severity of Spring grazing determine how many seed heads will be present in the pasture. Later regrowth will be mostly lower -toxicity leaves making late summer or autumn stockpiled forage lower in alkaloid content.

The greatest advantage with tall fescue is its ability to be stockpiled for winter grazing. It is productive in the fall, has its best nutritive value in cooler weather, withstands a lot of freezing and thawing while still maintaining yield and quality, and it provides solid footing in the muddy winters common in the lower Midwest and Upper South. I always say there are five good reasons for growing fescue: November, December, January, February, and March.

The final piece of living with endophyte infected tall fescue is having cattle with a high level of tolerance and environmental adaptation. Several seed stock producers including Pharo Cattle Co and Ozark Hills Genetics have been successfully selecting for fescue-tolerant cattle for a number of years. These cattle have proven to be adaptable to a wide range of environmental conditions and thrive in low-input production models in conjunction with sound grazing management. As these cattle have moved eastward into the tall fescue belt, they have shown their tolerance for fescue.

JimGerrishFencingAd2Taking a coordinated approach to fescue management that includes effective planned grazing, interseeding other pasture species, and choosing fescue-tolerant cattle can turn your fescue scourge into productive, cost effective pastures. Making a plan and implementing it is the first big step to living with endophyte infected tall fescue.



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Jim Gerrish
Jim Gerrish
Jim Gerrish is the author of "Management-Intensive Grazing: The Grassroots of Grass Farming" and "Kick the Hay Habit: A Practical Guide to Year-around Grazing" and is a popular speaker at conferences around the world. His company, American GrazingLands Services LLC is dedicated to improving the health and sustainable productivity of grazing lands around the world through the use of Management-intensive Grazing practices. They work with small farms, large ranches, government agencies and NGO's to promote economically and environmentally sustainable grazing operations and believe healthy farms and ranches are the basis of healthy communities and healthy consumers. Visit their website to find out more about their consulting services and grazing management tools, including electric fencing, stock water systems, forage seed, and other management tools.


  1. Jim,
    Thanks for continuing to grant permission to use what works here in the fescue belt. What opened my eyes: fescue this time of year is equal to or better feed quality than most hay produced here, most years. According to Extension Research in Ky and VA, my area. Once we switch to supplementing fescue with hay later this winter, the cows still prefer the fescue over the hay, sometimes even while the fescue is frozen. The cows tell me they like it, too, if I pay attention!

    Worth repeating that if applying N fertilizer do so in late summer, to push the fescue growth cycle which doesn’t seed out, and favor the diluting legumes in spring and summer.

    There are two weeds we clip to help limit seed set, in late spring/early summer. Fescue seedheads just forming may be a third ‘weed’ we clip then. Debatable whether running equipment over pasture pays, but if mowing high can cover lots of ground fast…and can also spot-clip those areas with more problems instead of mowing the whole.

    • Hey, that’s not living with it, that’s killing it!

      Replacing the infected fescue is certainly another viable option and, in a long term perspective, is generally a profitable strategy. How profitable depends on the landscape and what the cost of making the conversion ends up being.

      Where this strategy most often fails is when the landowner doesn’t change basic grazing management and allows the infected fescue to reestablish and overwhelm the replacement forage.

  2. About 25 yrs ago I contacted Jim Gerrish for advice on this very topic, and his advice was just as he has written here. I followed it pretty religiously with good results, but it takes PATIENCE to breed a herd that is well adapted. Some cattle do not show the obvious signs of fescue toxicity described here .but as Jim pointed out to me, they are sub-fertile, and thus not identified until 2-5 years old. It helps that such animals drop out as breeders, but only at some cost and frustration. By all means take care to select bulls from adapted parents, or at least from a trustworthy rancher, located in the fescue belt,who does not hide behind expensive supplements or other dodges, and keep records that will enable you to identify bloodlines that are fertile despite grazing toxic fescue. There are strategies to minimize intake of toxic seed in spring and summer, including use of herbicide and lots of mowing, but it’s cheaper to follow Greg Judy’s “mob grazing” strategies in which the cattle do the mowing. I was initially afraid of the risk of toxicity, especially for immature animals, but he was right- no problem. I see very young calves eating fescue seed heads without harm. Probably they soon develop temporary aversion that protects against overindulgence ( as described by Provenza), This experience might also foster gradual physiologic adaptation to the alkaloid toxins from ingested endophyte and thus enable the animal to tolerate and better utilize fescue as food. I found that my fat and fertile ‘granny’ cows excreted huge amounts of ergot alkaloid while grazing summer fescue. To prove tolerance in these cows, I sent samples to Agrinostics ltd, Watkinsville, GA to prove presence of these alkaloids in my pasture and ingestion by these cows.

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