🌾 Vet Nutrition 2025: Best Grazing Times for Horses to Avoid Fructan Overload 🐴🌅

Author: Dr Duncan Houston, BVSc

Turnout is great for horses—improving gut motility, reducing stress, and minimizing behavioral problems. But for some horses, especially those with insulin resistance or a history of laminitis, not all pasture time is created equal. In this 2025 guide, Dr Duncan Houston shares when it’s safest to allow grazing and how to manage the risks of high-fructan grass. 🐎🌱

🌞 Why Grazing Time Matters

Grass contains non-structural carbohydrates (NSCs), including fructans, which can cause severe issues in sensitive horses. These carbohydrates are produced through photosynthesis and vary throughout the day and seasons. 🌱🧬

When horses consume excess fructans, they bypass the upper gut and ferment in the hindgut, disrupting gut flora and triggering laminitis or founder. ❗

🧪 What Influences Fructan Levels?

• 📅 Season: High in early spring and fall during cool, sunny weather
• 🕒 Time of day: Lowest just before sunrise; highest late afternoon
• 🌿 Part of plant: Stems contain more fructans than leaves
• 🌾 Grass stress: Drought, frost, or overgrazing boosts fructan levels

🚫 Horses Most at Risk

• ⚖️ Overweight horses
• 🧬 Insulin-resistant horses (e.g., with Equine Metabolic Syndrome)
• 🔥 Horses with previous laminitis or founder

These horses should not be turned out freely and require strict pasture management or the use of a grazing muzzle. 🩺

🌄 Best Grazing Time: Early Morning

Because photosynthesis drives sugar production, fructan levels are lowest in the early morning, just before sunrise. That makes dawn the safest time for sensitive horses to graze. 🌅✅

📉 Worst Grazing Times: Afternoon and Cool Evenings

• 🌤️ Late afternoon: Peak fructan levels from full-day photosynthesis
• ❄️ Cool evenings with sunlight: Fructans accumulate and are not metabolized

Avoid grazing horses prone to laminitis during these times. 🛑

🛠️ Pasture Management Tips in 2025

• 🪚 Avoid overgrazing: Short grass = more stem = higher fructan
• 🧢 Use grazing muzzles to reduce intake without full restriction
• 💧 Ensure fresh water and access to low-NSC hay in dry seasons
• 🧬 Rotate turnout schedules for metabolic horses based on fructan patterns

🌿 What About Dead or Drought-Stressed Grass?

Don’t be fooled by brown grass! Stressed or frost-damaged grass can be high in fructans, even if it looks “dead.” These conditions still pose risk. 🚫

🧠 Dr Duncan Houston’s Advice

"Grazing can be healthy or harmful. For insulin-resistant horses, controlling when and how they graze is just as important as what they eat." 🐴🕒

📋 When to Call Your Vet

Consult your veterinarian if:

• 📉 Your horse has had laminitis or founder
• ⚖️ You’re unsure if a grazing muzzle is appropriate
• 🩺 You need a diet plan for insulin resistance or EMS

🔚 Final Thoughts: Safe Grazing = Smarter Grazing

Letting horses graze supports their natural behaviors and health—but for at-risk horses, timing is everything. Grazing in the early morning, managing pasture height, and using muzzles can help protect your horse’s hooves and metabolic health. 🐎🌾

Need personalized grazing or nutrition advice? Visit AskAVet.com or download the Ask A Vet app for real-time support from licensed equine professionals. 📱🐴