🧬 Vet Guide 2025: Understanding Digestion in Horses—From Forage to Fermentation 🐴🌿

Author: Dr Duncan Houston, BVSc

Equine digestion is unlike that of other domestic animals. Horses have evolved to graze continuously on native grasses, not consume large, grain-heavy meals twice a day. Unfortunately, modern feeding practices clash with their natural design—leading to problems like colic, gastric ulcers, and laminitis. In this 2025 guide, Dr Duncan Houston explains how the equine digestive system works and how you can support your horse’s health through proper feeding. 🐎🧠

🩺 How the Equine Digestive System Works

Horses have a monogastric system (like humans and dogs), meaning a single-chamber stomach. However, they also possess a cecum—a large fermentation chamber that functions similarly to the rumen in cattle. 🌾

Key Differences from Other Animals:

• 👨‍⚕️ Simple stomach like humans and dogs
• 🐄 Hindgut fermentation via the cecum, unlike cattle’s foregut rumen

This combination means horses can digest grains, fats, and proteins in the small intestine—but rely on their hindgut to ferment fibrous forage. 🧬

🌿 The Role of Forage in Horse Digestion

Horses evolved to graze continuously on low-calorie grasses, spreading their food intake over 16–18 hours daily. Modern feeding—two meals in a stall—is the opposite of what they need. 🔄

Modern Feeding Problems:

• 🍽️ Large grain meals stress the small intestine
• ⏱️ Long fasting periods lead to gastric ulcers
• 💥 Excess carbs reaching the cecum disrupt fermentation and lower pH

The result? Increased risk for colic, founder, and digestive inflammation. ⚠️

🧠 Small Intestine: Primary Digestion Site

The small intestine is where digestion of proteins, fats, and non-structural carbohydrates occurs. Horses don't have a gall bladder, but they still digest fat efficiently because bile flows directly from the liver into the intestine. 🧴

Digestion Highlights:

• 🥩 Protein and fat breakdown starts in the small intestine
• 🍞 Sugars and starches are also absorbed here—until overloaded

When too many carbs escape digestion here, they ferment in the cecum. This leads to an acidic hindgut and dangerous health consequences. 🧪

🦠 Cecum: The Fermentation Powerhouse

The cecum is packed with bacteria and microbes that ferment undigested fiber. This is how horses extract energy from hay and pasture. However, this system is delicate and easily disrupted. 🌱

Problems Occur When:

• ⚠️ Starch overload enters the cecum
• 📉 pH drops, killing beneficial microbes
• 🧬 Endotoxins are released, causing laminitis, colic, and inflammation

Protecting cecal health is one of the most important goals in modern equine feeding. 🧫

📋 Dr Duncan Houston’s Feeding Tips (2025)

• 🌿 Make forage (pasture or hay) 75–100% of the diet
• 🥕 Use grain only when needed, and in small, frequent meals
• 🕒 Feed on a consistent schedule
• 🚶‍♂️ Provide turnout and movement to aid GI motility
• 💧 Ensure constant access to clean, fresh water

🧠 Dr Duncan Houston’s Insight

"The horse’s gut is built for slow, steady grazing—not twice-daily carb bombs. The more we feed like nature intended, the healthier your horse will be." 🐴🌿

🔚 Final Thoughts: Feed the Gut Right

Understanding digestion in horses helps you make informed choices about feeding, turnout, and care. From the single stomach to the fermenting cecum, your horse’s digestive system is complex—and easily upset. Stick with forage-first diets, avoid sudden changes, and you’ll set your horse up for long-term GI health. 🐎❤️

Need feeding help or a gut health consult? Visit AskAVet.com or download the Ask A Vet app for expert equine nutrition and GI support. 📱🧴