☠️ Vet Guide 2025: Plant Toxins and Liver Disease in Horses—What You Need to Know 🐴🌿

Author: Dr Duncan Houston, BVSc

Liver disease in horses is uncommon—but when it happens, it’s usually due to ingesting toxic plants or contaminated feed. Many common weeds and molds produce powerful toxins that damage liver cells, sometimes fatally. In this 2025 guide, Dr Duncan Houston explains the top plant and feed-related liver threats and how to protect your horse. 🐎🧠

🔬 Signs of Liver Disease in Horses

Liver issues often develop slowly. Watch for:

• 📉 Decreased appetite
• 😴 Depression or lethargy
• 💢 Colic-like symptoms
• 😮 Yawning or odd behaviors
• 🟡 Yellow mucous membranes (jaundice)

Early veterinary diagnostics and liver enzyme tests are essential to detect issues before they become severe. 🧪

🌱 Dangerous Plants to Avoid

🧪 Pyrrolizidine Alkaloid Plants

These toxic compounds accumulate over time and destroy liver cells. Horses may not show signs until significant damage is done.

• 🚫 Senecio
• 🚫 Groundsel
• ⚠️ Often consumed when baled in hay or when pasture is sparse

🌿 Cocklebur (Xanthium strumarium)

Common in western states, this plant is most toxic at the seedling stage, especially in early spring.

• 🌱 2-leaf seedlings contain high toxin levels
• 🍂 Horses eat it when forage is scarce

💡 Prevent access by providing hay early and monitoring pasture growth. 🚫

🌾 Grain-Related Toxins

🔥 Aflatoxin

Aflatoxin is a toxin produced by mold on grain crops, particularly during warm, damp conditions.

• 🌽 Found on corn, sorghum, and other grains
• 💨 Mold may not be visible—but toxins still present

Prevention Tips:

• ✅ Buy feed from reputable suppliers
• 🏠 Store feed in a cool, dry place
• 🔬 Ask for or perform aflatoxin testing on suspicious feed

💧 Blue-Green Algae (Cyanobacteria)

This microscopic organism can cause algal blooms in warm weather, especially in stagnant ponds.

• 🌊 Forms a green or colorful sheen on the water
• ☠️ Produces toxins harmful to the liver

Do this if you spot an algal bloom:

• 🚱 Remove horses from the pasture immediately
• 🚰 Provide an alternative clean water source

🧠 Dr Duncan Houston’s Advice

"Liver disease is often silent until it’s severe. Prevention starts with pasture management, safe feed storage, and early veterinary screening." 🐴🧬

✅ Key Prevention Steps

• 🌱 Identify and remove toxic plants from pastures
• 🍽️ Feed clean, mold-free hay and grains
• 🔍 Inspect feed ingredients and hay for unusual weeds
• 💧 Test pond water if algal bloom is suspected
• 🩺 Get liver values checked in lethargic or anorexic horses

🔚 Final Word: Prevent the Poison

Many cases of liver disease in horses are entirely preventable. A keen eye on forage, feed quality, and water safety can protect your horse from irreversible liver damage. 🐎💚

Need help with toxin identification or liver health support? Visit AskAVet.com or download the Ask A Vet app for expert help today. 📱☠️