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 or 2020. 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 2021 foaling season was estimated to be $471,544 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 $1.87 million dollars over the four foaling seasons.