Toxigenic Endophyte-Infected Tall Fescue and Ergot Alkaloids

Area of Science:

• Veterinary Medicine
• Toxicology
• Equine Reproduction

Background:

• Fescue toxicosis and reproductive ergotism manifest as similar toxidromes in pregnant mares.
• These conditions are collectively termed equine ergopeptine alkaloid toxicosis (EEPAT).
• Both syndromes stem from ergopeptine alkaloids (EPAs) of fungal origin.

Purpose of the Study:

• To identify the common cause and clinical presentation of fescue toxicosis and reproductive ergotism in equids.
• To define equine ergopeptine alkaloid toxicosis (EEPAT) as a unifying diagnosis.
• To outline the reproductive consequences and prevention strategies for EEPAT.

Main Methods:

• Clinical case review and toxicological analysis of ergopeptine alkaloid (EPA) exposure in equids.
• Comparative analysis of toxidromes associated with tall fescue endophyte infection and Claviceps purpurea.
• Literature synthesis on the pathophysiology and clinical signs of EEPAT.

Main Results:

• EEPAT presents identical clinical signs in late-gestational mares, including hypoprolactinemia-induced agalactia/dysgalactia, prolonged gestation, and dystocia.
• Foals born to affected mares often exhibit dysmaturity and failure of passive transfer.
• EPAs originate from Epichloë coenophiala in tall fescue or Claviceps purpurea in other grasses.

Conclusions:

• EEPAT is a significant reproductive hazard in horses, caused by fungal EPAs.
• Effective prevention strategies include minimizing exposure to contaminated forages and addressing hypoprolactinemia.
• Understanding the shared etiology of these conditions is crucial for equine reproductive health management.