Tall Fescue

One of the most common grasses found in central Kentucky horse pastures is KY-31 tall fescue. It is a coarse-bladed grass that tends to grow in clumps, although it can be widespread throughout a field. The leaf blade is abrasive when felt along the edge, and it has clear striations running down the leaf. The base of each blade is round and it is a deeper green when compared to other grasses during the growing season.

KY-31 tall fescue is a hardy cool season grass that is drought and cold tolerant that stands up to heavy use. These characteristics are due to the symbiotic relationship with the endophyte found within the plant. Although this gives the grass its resilience, the endophyte also produces a toxin which can be harmful to late term pregnant mares. This toxin, called ergovaline, can cause agalactia, dystocia, red bag, and late term abortion. Ergovaline concentrations vary both seasonally and between individual plants. Sensitivity to this toxin also varies between mares.

When managing broodmares, it is important to know how much of their pasture is comprised of KY-31 tall fescue. Although fescue is less palatable than other grasses, the horses will consume it if the field has been overgrazed or other forage options are limited. Implementing good pasture management practices will help mitigate the risks associated with grazing tall fescue. This includes ensuring that fields receive enough rest in order to bounce back after use along with seeding other desirable grasses.

KY-31 is not the only commercially available tall fescue variety. Several novel varieties have been developed with the benefits of an endophyte that do not produce the ergovaline toxin. Because these novel varieties are genetically different, they are safe for all class of horse. However, both KY-31 and novel tall fescue look the same and require a lab test to differentiate between the two. Therefore, it is not recommended to seed into existing KY-31 stands. Seeding novel tall fescue is a great option for farms with little KY-31 tall fescue present or those looking to fully renovate fields.

While KY-31 tall fescue is prevalent throughout central Kentucky, understanding its effects is crucial to broodmare management. Knowing the composition of your fields allows for appropriate planning to reduce the risks associated with grazing tall fescue. Maintaining a strong stand of desirable grasses, including bluegrass, orchardgrass, and novel tall fescue maximizes land use and provides safe pastures for all horses.

Seasonal Tip: Apply fertilizer after a killing frost!