🌾 Vet Guide: Hay & Pasture Testing for Winter | 2025 Nutrition Tips for Metabolic Horses 🐴

By Dr Duncan Houston, BVSc

As temperatures drop and pasture quality declines, horse owners turn to hay to keep their horses fed through the winter. But not all hay is created equal—and for horses with **Cushing’s (PPID)** or **equine metabolic syndrome (EMS)**, the wrong hay can lead to serious health consequences. 🐴❄️📉

In this 2025 guide, I’ll explain why hay and pasture testing is essential this time of year, how to collect samples correctly, and how to protect insulin-resistant horses with simple, smart nutrition planning. 🧠🌿

🍂 Why Hay Matters More in Fall & Winter

During the growing season, horses can graze fresh pasture. But as fall sets in, grass loses nutritional value—and sugar content may spike during cold weather. This is especially risky for horses with metabolic issues. 🍁🧪

As pasture fades, hay becomes the primary forage. But **hay can vary dramatically** in sugar and starch levels. According to Equi-Analytical Lab, **grass hay** can range from **5% to 35% non-structural carbohydrates (NSCs)**. That’s a huge swing. 📊

🚫 Horses at Risk Include:

• 🧬 Horses with insulin resistance
• 🧠 Horses with PPID (Cushing’s disease)
• ⚖️ Overweight or laminitis-prone horses

For these horses, hay should be **under 10% NSC**. Anything higher increases the risk of metabolic flare-ups and laminitis. ⚠️

🧪 How to Test Hay for Sugar & Starch

If your hay supplier doesn’t provide testing results, it’s up to you to ensure your horse’s safety. Here’s how to sample and submit hay for lab analysis: 🧤🛠️

🧰 Supplies You’ll Need:

• 🔩 Hay probe (core sampler)
• 🔋 Electric drill (to power the probe)
• 📦 1-quart sealable plastic bag
• 📋 Access to a lab like Equi-Analytical or Dairy One

📦 Sample Collection Instructions:

• 📦 Select at least **10 random bales** from your batch
• 📌 Probe each bale through the **center of the side** (not the end)
• 🔄 Mix all samples together in a clean bucket or bag
• 📬 Send at least **1 pound** of mixed hay to the lab

You can request a full nutrient profile, but for metabolic horses, a **simple starch and sugar panel** is usually enough. This is affordable and worth every penny. 🧪💰

🌱 How to Sample Winter Pasture

Pasture can still be a factor in winter feeding, especially in mild climates. If you want to test pasture, here’s how to do it right: 📋🌿

📏 Pasture Sampling Steps:

• 🔍 Identify the areas your horse actually grazes
• ✂️ Use scissors to clip **20+ small samples** from different areas
• 🚫 Do not include plant bases or roots—only the top portion the horse eats
• 📏 Cut into 2-inch segments and mix thoroughly
• 🧪 Send sample to the same lab you use for hay

This provides an accurate reading of sugar content in your pasture during fall or winter. 🌬️🌾

📉 What Are Acceptable NSC Levels?

NSC = Non-Structural Carbohydrates, which include sugars (WSC) and starches. For metabolic horses, the following are general guidelines: 🧠📊

• ✅ Safe: Under 10% NSC
• ⚠️ Moderate risk: 10–12% NSC
• 🚫 High risk: Over 12% NSC

Anything above 10% for an insulin-resistant horse should be avoided—or soaked in water to reduce sugar before feeding. 💧🐴

🛡️ Tips to Protect Horses with PPID or EMS

Fall is one of the most dangerous seasons for laminitis, especially in older or overweight horses. Here’s how to feed safely: 🧠⚖️

• 🧪 Always test hay before buying in bulk
• 📉 Feed **under 10% NSC** for at-risk horses
• 💧 Soak hay in cold water for 30–60 minutes to remove sugars
• 📦 Store hay off the ground to prevent mold and spoilage
• 📋 Monitor weight and body condition regularly

High sugar hay can undo months of careful metabolic management. Knowledge is power. 📉🧬

📲 Use Ask A Vet for Forage Planning

The Ask A Vet app helps you interpret hay test results and plan feeding strategies. Use it to:

• 📤 Upload lab results for vet feedback
• 📏 Get hay alternatives for high-NSC batches
• 📊 Track weight and body condition over winter
• 📦 Find low-starch, tested hay suppliers

It’s your personalized forage guide for safer winter feeding. 🐴📲

✅ Winter Hay Testing Takeaways

• 🌾 Hay and pasture sugar content varies widely—test, don’t guess
• 🧪 Use a hay probe and send a proper sample to a certified lab
• 📉 Metabolic horses need hay under 10% NSC
• 💧 Soak high-NSC hay to reduce risk if needed
• 📱 Use Ask A Vet to build a custom, season-safe feeding plan

📲 Final Thoughts from Dr Duncan Houston

Hay testing isn’t just for feed stores or large operations—it’s for every horse owner who wants to feed with confidence. Especially if you manage a horse with metabolic disease, **testing hay and pasture is one of the most powerful things you can do** to protect your horse this winter. 🧠🌾

Use the Ask A Vet app to interpret your test results and keep your horse on the right nutritional path, no matter the season. 🐎📱