Specialists Involved: Jimmy Henning, Ray Smith and Krista Lea

A central Kentucky thoroughbred horse farm experienced a high incidence of fescue toxicosis symptoms in pregnant and foaling mares during early 2017. The UK Plant and Soil Science Forage Group was contacted by the farm at the advice of the consulting veterinarian. After a farm visit, the farm agreed to a program of pasture evaluation. Fields were samples for species composition, endophyte infection level, and ergovaline content. After being presented results showing damaging levels of infected tall fescue, the farm began an aggressive program of fescue eradication in some fields and complete re-establishment in two others. They also changed their pasture usage for foaling mares in the 2018 season to avoid exposure to toxic tall fescue.

As a result of the knowledge of fescue presence and fescue eradication in selected pastures, the farm was able to avoid exposing pregnant mares to toxic tall fescue. As a result, the farm experience no difficulty in foaling (dystocia) and fewer thickened placentas (red bags) and no foal losses due to tall fescue in 2018, 2019, 2020, 2021 and 2022. Dystocia and thickened placentas are indicators of fescue toxicity in pregnant mares.

Fewer fescue-related foal deaths and associated syndromes resulted in four more live foals and greatly reduced veterinary costs in each year compared to 2017. The economic impact of having four more foals in the 2022 foaling season was estimated to be $475,000 using the 2089-2020 three-year average Keeneland September yearling sale figures.

The total economic benefit to this farm from adopting UK forage management recommendations exceeds $2.345 million dollars over the five foaling seasons.

In a related outcome, this farm has expanded by purchasing an additional 200 acres to give their existing pastures more rest. These pastures will be sampled for endophyte presence and ergovaline concentration and mares will be stocked accordingly. The farm manager credits the UK Equine Pasture Evaluation Program for the improved ability to manage pastures and control foaling difficulties due to tall fescue.