Infested pastures can harm cattle

David Burton

Toxin in fescue can restrict the flow of blood to animals' ears and rear limbs.

Fescue foot can show up almost any time of the year, but the cold months of December, January and February are usually the worst.

Fescue foot results from cattle grazing endophyte-infected fescue pastures that — for several reasons — produced a large amount of an ergot-like toxin.

The most prevalent toxin, ergovaline, causes a constriction of the blood vessels in some animals.

That results in less blood flowing to the extreme parts of the body (rear legs and feet, tail and ear tips), according to Eldon Cole, livestock specialist with the University of Missouri Extension.

"Poor circulation is often first noted in cattle when they get up in the morning and appear slow and a little 'ouchy' on their rear feet," said Cole.

There may be no other visible signs unless the cattle are closely inspected in a chute. Then, the rear limbs may feel cool to the touch because of the restricted blood flow.

"If no action is taken the cattle's condition can worsen, and extremely cold, snowy weather may result in frostbite to the feet and lower legs," said Cole.

A break in the skin around the hoof-dewclaw area can appear as if a wire had been placed tightly around the area.

According to Cole, in extreme situations the hoof can actually slough off.

"The most effective thing to do when you notice the limping on the rear legs is remove the cattle from the fescue pasture. Even putting them on another fescue field that may have lower toxin levels can be a benefit," said Cole.

In severe cases, putting cattle up in a dry lot and feeding grain and legume hay can help some.

"Antibiotic treatments are of little value other than preventing infections that could arise. So far, there are no magic formulas to correct the problem," he said.

Toxin levels in the fescue tend to decline into the winter," said Cole.

Some fields of fescue seem to be problems every year while others may go for years with no ill-effects. According to Cole, sensitive cattle that show the symptoms but recover may lose their tail-switch or show up the following summer with long toes on their rear feet.

The new, novel friendly-endophyte-bearing fescue variety does not show fescue foot or the warm weather symptoms associated with fescue toxicosis.

"The new friendly-endophyte fescue is recommended when new seedings of fescue are made. In other fescue pastures — not destined for renovation — every attempt should be made to add legumes to those fields," said Cole.

For more details, visit with your local University of Missouri Extension center and request MU guide sheet G4669, "Tall Fescue Toxicosis."