animals and competing plants. Fescue plants carrying the fungus are said to be endophyte-infected. Not every plant is infected, but at least 90 percent of our fescue fields contain high endophyte levels.
On paper, the nutritional value of fescue is similar to other forages, but actual livestock performance can be disappointing. Although a clear link between the alkaloids and palatability has not been proven, grazing animals do avoid fescue in favor of better-tasting forages when given a choice.
Animals limited to a steady fescue diet often display higher than normal body temperature and respiration rates, decreased food intake and reproductive problems. The combination of these symptoms is often called "summer slump" because they worsen as rising temperatures make it difficult for animals to dissipate excess body heat. Affected animals spend more time trying to stay cool and less time grazing, which sharply reduces their rate of weight gain and milk production.
According to a 1990 study, losses to the U.S. beef industry from these symptoms top $609 million annually, so it may be hard to understand why cattlemen still favor fescue.
It may be that any income lost due to poor animal performance is offset by the fact that they can stock more animals per acre of fescue. It's also cheaper and takes less time to maintain fescue pasture than pasture dominated by other forages.
In addition, fescue withstands the elements after the growing season ends better than most grasses, allowing it to be stockpiled for grazing well into the winter. Stockpiling fescue saves time and money by reducing the need for feeding hay.
Fescue sod withstands vehicle traffic and livestock trampling, providing a good place for calving and winter-feeding. Also, fescue sod effectively resists erosion and helps save precious topsoil. These qualities make fescue a suitable turf grass, which has generated an entire industry. Each summer, Missouri farmers harvest about 75 percent of the Kentucky 31 tall fescue sold in the U.S. This market produces positive cash flow during the summer, when little else on the farm is ready to be sold.
Plant breeders have developed endophyte-free fescue varieties to curtail the animal health problems linked to infected fescue. However, these varieties are not popular as forages or seed sources because they lack the resiliency provided by the endophyte. Researchers are currently developing fescue varieties that contain "friendly" endophytes that maintain host plant resilience without creating health problems for livestock. This line of research may benefit