Tall fescue, a cool-season grass, has become the basis for most pasture systems in our region.  In fact we are part of what is referred to as the “fescue belt.”

As a pasture grass, fescue is productive, relatively high quality and very persistent. Some people believe that its persistence (call it “toughness”) has kept a lot of cattlemen in business over the years.

The downside of fescue is also the reason it is so tough. It can be infected with a fungus that helps the plant survive harsh conditions, but also makes it poisonous. This “fescue toxicosis” restricts blood flow in cattle causing them to overheat in the summer and their extremities to freeze in the winter. Not only is it hard on cattle, it also harmful to horses especially pregnant mares. Without this fungus, fescue loses its toughness and either won’t persist or gets re-infected again by nearby infected fescue.

A lot of research is being done on this issue, and the more we know the worse it gets. In cattle the problems caused by infected fescue include reduced gain, reduced fertility, as well as a host of acute health issues related to the restricted circulation and increased body temperature. It is easy to notice cows limping around from fescue foot, losing the end of their tails or not shedding, three very visible symptoms of fescue poisoning. What is less easy to notice is calves putting on poor rates of gain and cows not breeding back on time. Even when these symptoms are noticed, they often aren’t attributed to fescue. If the cows aren’t limping and calves aren’t wooly, many producers don’t associate other problems with infected fescue. 

Avoiding these problems is a challenge in our part of the country where fescue has become such an important forage. Some of the options that can be taken into consideration include:

•Dilution by inter-seeding other forages such as clover or lespedeza. Warm season legumes, under the right conditions, can produce improved pasture quality when fescue is most toxic. There is some evidence that this isn’t as effective as once thought, but it does help to some extent.

•Proper grazing and management. It is known that most of the poisons from the fungus are concentrated in the seed heads and the lower two inches of the plant. By clipping mature stands of fescue to remove the seed head and not grazing too short, the most poisonous parts of the plant can be avoided.

•Moderate nitrogen fertilization. Growth driven by high application rates of nitrogen fertilizer has higher levels of toxicity.  Backing off on nitrogen fertilizer or relying on legumes for nitrogen will help reduce problems.

•Add warm season grass pastures to the grazing system. Having pastures with warm season grasses (blue stem, switch grass, etc.) allows you to move cattle off of fescue in the summer months when the effects from the poisons are the highest. Warm season grass pasture also provide better grazing during periods of drought when fescue growth stops and ends up getting grazed too short (and into the part of the plant that is more poisonous).

•Renovate pastures with non-toxic fescue. It has been found that other, non-poisonous types of fungus can be used to infect fescue providing the benefits without the toxicity. Several varieties of these “novel endophyte” infected fescues are on the market and recommendations for successful renovation are available. This is an expensive and time-consuming process but more and more producers are finding that eliminating the problems caused by poisonous fescue pays off in the long run.

These are just some of the options addressing the issues caused by grazing poisonous fescue.  It is important that producers are aware that problems exist, watch for symptoms and consider ways to address the underlying problem of poisonous fescue.

Announcements and upcoming events:

•Texas County Forage and Beef Conference – March 21.

•Fruit Tree Workshop – March 23.

Eric Meusch is an ag educator with the University of Missouri Extension. To contact him, call the Extension office in Houston at 417-967-4545 or email meusche@missouri.edu. The office is at 114 W. Main St. in Houston. Hours are 8 a.m. to 4 p.m., Tuesday through Friday.

Leave a comment

Leave a Reply