Living With Endophyte Infected Tall Fescue

The 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. [caption id="attachment_16723" align="align

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4 thoughts on “Living With Endophyte Infected Tall Fescue

  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.

    1. 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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