🩺 Aflatoxin Poisoning in Horses: A Vet’s 2025 Guide | Dr Duncan Houston BVSc

Meta description: Learn how aflatoxins from moldy feed lead to liver damage, immunosuppression, and neurologic signs in horses—treatment, prevention, and Ask A Vet support for safe nutrition in 2025.

1. 🍄 What Are Aflatoxins?

Aflatoxins are potent mycotoxins produced by *Aspergillus flavus*, *A. parasiticus*—often found in moldy corn, grains, nuts, hay, and oilseeds when stored in warm, humid conditions (>21 °C, high moisture) :contentReference[oaicite:3]{index=3}. Aflatoxin B₁ is the most toxic, metabolized in the liver to a harmful epoxide that causes DNA damage, immunosuppression, and liver failure :contentReference[oaicite:4]{index=4}.

2. ⚠️ Why Horses Are Susceptible

Though rare, horses are sensitive to aflatoxicosis. Warm, humid climates, drought-stressed crops, poor storage, and insect damage create ideal conditions for mold growth :contentReference[oaicite:5]{index=5}. Cases may go unnoticed until multiple horses fall ill due to contaminated feed.

3. 🩺 Signs & Clinical Manifestations

Acute Exposure

• Sudden death or acute liver failure without warning. Acute aflatoxicosis often ends fatally :contentReference[oaicite:6]{index=6}.

Subacute & Chronic Exposure

• Depression, anorexia, fever, weight loss, rough coat, poor growth, and anemia :contentReference[oaicite:7]{index=7}.
• Gastrointestinal signs: colic, diarrhea, bloody feces :contentReference[oaicite:8]{index=8}.
• Jaundice (yellow mucous membranes), bruise susceptibility, epistaxis :contentReference[oaicite:9]{index=9}.
• Neurologic tension: tremors, ataxia, muscle spasms, seizures :contentReference[oaicite:10]{index=10}.
• Chronic signs include recurrent respiratory issues, possibly linked to aflatoxin inhalation :contentReference[oaicite:11]{index=11}.

4. 🔎 Diagnostic Approach

• History & feed inspection for mold presence.
• Blood tests: elevated liver enzymes, elevated bile acids, altered albumin/globulin ratio, anemia, clotting abnormalities :contentReference[oaicite:12]{index=12}.
• Feed analysis via HPLC or ELISA for aflatoxin B₁ levels :contentReference[oaicite:13]{index=13}.
• Liver ultrasound or biopsy in chronic cases :contentReference[oaicite:14]{index=14}.
• Necropsy: jaundiced liver with centrilobular necrosis, hemorrhage :contentReference[oaicite:15]{index=15}.

5. 🛠️ Treatment & Supportive Care

No specific antidote exists. Treatment focuses on eliminating toxin exposure and supporting liver function:

• Immediate removal of contaminated feed :contentReference[oaicite:16]{index=16}.
• Activated charcoal orally to reduce absorption :contentReference[oaicite:17]{index=17}.
• IV fluids with dextrose to support hepatic metabolism.
• Vitamin K and B-complex support for clotting and metabolism :contentReference[oaicite:18]{index=18}.
• Liver protectants—SAMe, silymarin, milk thistle—as per vet guidance.
• Antimicrobial therapy if immunosuppressed or secondary infection suspected :contentReference[oaicite:19]{index=19}.
• In chronic cases, prolonged rest and monitoring—recovery may be slow and incomplete.
• Toxin binders like hydrated sodium calcium aluminosilicates (HSCAs) may reduce absorption—industry use is common though not FDA-approved :contentReference[oaicite:20]{index=20}.

6. 🛡️ Prevention & Feed Management

• Store feed dry (<7% moisture), cool, pest-free—regular bin cleaning minimizes contamination :contentReference[oaicite:21]{index=21}.
• Implement first-in-first-out use; monitor for mold or dust.
• Avoid feeding whole mold-prone grains (corn, cottonseed) without testing :contentReference[oaicite:22]{index=22}.
• Periodic feed testing during hot, humid seasons :contentReference[oaicite:23]{index=23}.
• Consider toxin-binding supplements during high-risk periods :contentReference[oaicite:24]{index=24}.

7. 💬 Ask A Vet Tailored Support

With Ask A Vet, you gain access to:

• 📋 Feed and hay audits—upload photos/videos for contamination assessment.
• 📆 Dosing & monitoring plans for charcoal, IV fluids, vitamins.
• 📊 Bloodwork review, liver enzyme monitoring, recovery trajectory insight.
• 🎓 Webinars: “Mycotoxin prevention,” “Liver support protocols,” “Safe feed storage.”
• 🤝 Long-term follow-up: adjust nutrition, recheck schedules, binder use guidance.

8. ❓ Frequently Asked Questions

Q: How much aflatoxin is toxic?

Levels >0.5–1 ppm can injure liver; >2 ppm may be fatal :contentReference[oaicite:25]{index=25}.

Q: Can horses recover fully?

Yes—for mild to moderate cases with supportive care; advanced liver damage may cause lasting deficits.

Q: Are toxin binders safe?

They reduce absorption but don’t eliminate toxins—should supplement thorough feed management :contentReference[oaicite:26]{index=26}.

Q: Should I test hay?

Yes—especially corn-based or dusty feeds in humid climates. Labs use ELISA or HPLC to detect aflatoxin.

9. ✅ Final Takeaway

Aflatoxin poisoning is rare but may be lethal. Vigilant feed management, mold monitoring, charcoal use, liver support, and binder programs help protect your horse. As Dr Duncan Houston, I recommend Ask A Vet for real-time feed audits, customized care plans, and ongoing liver monitoring—to keep your equine partner safe and thriving in 2025 and beyond.