Claviceps fungal spores are found in soil in much of the U.S. and infect the seeds of many grasses, particularly during wet spring months. This infection results in sclerotia (also called ergot bodies) growth instead of a healthy seed.
The sclerotia, which look like mouse droppings, contain concentrated levels of many ergot alkaloids. A number of these alkaloids are similar to the major toxin found in endophyte-infected tall fescue and can cause clinical signs similar to those seen in mares with fescue toxicosis.
To reduce the risk of ergot poisoning, keep pastures clipped to remove seedheads. Check hay and bedding for presence of ergot bodies. Because of the raking and baling process, ergot bodies in hay or bedding are rare, but can occur.
Cynthia Gaskill, DVM, PhD, Dipl. ABVT, veterinary clinical toxicologist at UK’s Veterinary Diagnostic Laboratory; Ray Smith, PhD, forage extension specialist within UK’s Department of Plant and Soil Sciences; and Krista Lea, MS, research analyst and coordinator of UK’s Horse Pasture Evaluation Program, provided this information.