Tall fescue is the most common cool-season pasture grass I see in Missouri. And most of it is infected with the fungus Neotyphodium coenophialum. The fungus is often called "endophyte." Endo means "inside" and phyte is "plant."

The concern with the fungus growing inside the plant is that, although the fungus improves the survivability of the fescue, the fungus also produces ergot alkaloids, which are toxic to animals. From a plant's perspective, this is great. The fungus improves the plant's ability to compete and hammers plant predators. The use of endophyte-free fescue has been triedÑit does improve animal performance, but stand persistence has been low, especially if the area is prone to drought.

Endophyte-free grass is more prone to being eaten by insects, mammals or attacked by pathogens.

The use of novel, non-ergot-producing endophyte infected fescue has been tried as well, to varying results. Novel-endophyte plants are protected via patents and shouldn't be harvested for replant.

Ergot alkaloids produced by the endophyte include: lysergic acid, clavine alkaloids and ergopeptines. The alkaloids are found in stem, leaf and seed tissue; they are highly concentrated in the seed.

Probably the most work has been done on the compound ergovaline, but there is ongoing discussion as to which compounds actually cause the problems.

In spring, the plant's concentration of alkaloid levels jump as soon as the heads appear. Levels decline during fescue's dormant summer stage, then spike up again in the fall, when growth picks back up. The biggest reduction in animal performance seems to occur when the levels of toxic compounds in the plants are falling or flat. This indicates that there is a lingering effect of consuming infected fescue. In the spring, animals eat high levels, then as the summer moves on, heat stress makes the situation worse.

The thought among nutritionists and animal physiologists is that it takes 6 to 8 weeks to clear an animal of toxins once feeding of infected fescue is stopped.

"Fescue foot" or a tail falling off are pretty dramatic signs of problems with fescue. Most of the time far milder things are seen.

Common symptoms are calves shedding their winter coats, increased body temp, increased breathing rate, standing in ponds, low feed intake, low average daily gain, reproductive problems (no milk, calving problems, thick placentas, cows didn't clean, etc.).

At this time, we think that dealing with fescue and animals comes down to dealing with the amount of ergot alkaloids.

For rough work, estimate that for every 10 percent infection you have on a fescue pasture, you lose 0.1 lb. ADG. Yes, animals can lose weight on fescue pastures.

Some things that really are good for grass, (i.e. high amounts of nitrogen) make it more challenging to handle the alkaloids-because alkaloid concentration increases with increasing nitrogen applications.

From an animal perspective, you need to do something about the load the animals are eating prior to seeing the symptoms of fescue toxicity.

Limiting nitrogen application tends to reduce ergot alkaloids, but I am not a fan for managing for low yields.

Aggressive legumes, such as a red clover, will dilute out the fescue. Often a couple pounds of clover seed are spread with fertilizer. You can use non-fescue summer pastures while saving fescue pastures as stockpiled feed for cows. Work at MU has shown that alkaloid concentrations fall during the winter.

In supplemental feeding of concentrates, the gold standard is hand feeding at 0.25 percent to 0.5 percent of body weight per day. Feeding concentrates on growing calves substantially improves their performance. If you need to offer feed ad lib, MFA TrendSetter SLR is the product of choice.

Over the years I have worked with Tasco (seaweed), FEB-200 (yeast cell walls), and Bio-stim (cell walls and clays) CTC, thiamine, and Bovatec.

If I had to use infected fescue, my first preference would be to feed about 0.5 percent to 1 percent body weight of an MFA complete feed. By doing so in the spring and fall during rapid grass growth, I would pick up the effects of dilution, better protein efficiency, additive effects and trace mineral-vitamin supplementation.

For stockpiled fescue when the alkaloids are lower and for cows, I'd feed a couple to 4 pounds of breeder cubes. I would use TrendSetter on the calves. If I was in a situation where I was only using a mineral addition, I would use a mineral balanced for cool-season grasses, such as Fescue Equalizer with CTC and aggressive levels of vitamin A, zinc and copper. XI mineral would also be a good choice.