Can You Feed Your Horse Alfalfa? What To Know

Yes — if it fits your horse’s individual needs.
Alfalfa is one of the most debated forages in the equine world. Some swear by it for performance, others fear it will make their horse “hot.” But what’s the truth?

This guide will walk you through the nutritional science, risks, benefits, and best practices of feeding alfalfa — so you can make the right decision for your horse, whether they’re a high-level athlete, an easy keeper, or something in between.

What Is Alfalfa and Why Is It Fed to Horses?

Alfalfa is a legume hay, rich in protein, calcium, and digestible energy. It has long been used in equine diets, particularly for:

• Performance horses
• Lactating or pregnant mares
• Foals and young growing horses
• Hard keepers or seniors with dental issues

Its high nutrient density makes it especially useful for horses with elevated nutritional requirements. However, feeding too much to low-need horses (like idle geldings) may lead to unwanted weight gain and behavior issues from insufficient gut fill.

🟢 Fun fact: Alfalfa has a higher acid-buffering capacity than grass hay, which can help protect against gastric ulcers when fed before exercise.

Nutritional Breakdown of Alfalfa Hay

Here’s a typical nutritional profile of good-quality alfalfa hay:

🔍 Takeaway: Alfalfa offers excellent nutrition but easily exceeds the requirements of most mature horses at maintenance or light work.

Is Alfalfa Safe for All Horses?

Not every horse benefits from alfalfa. Here’s how it matches different equine needs:

Does Alfalfa Make Horses “Hot”?

One of the most common beliefs is that alfalfa makes horses hot, spooky, or reactive. But is it true?

Here’s what the research says:

• Alfalfa is low in sugar and starch, so it doesn’t spike blood sugar.
• There is no direct scientific link between alfalfa and hyperactivity.
• The issue often comes from too many calories, not the forage type.

If your horse is overfed (regardless of feed type), you may see excess energy and excitability. Balancing the diet to match workload is key.

Understanding the Protein in Alfalfa

Alfalfa is rich in crude protein — and that’s not a bad thing. Horses use protein for:

• Muscle repair
• Growth
• Milk production
• Tissue maintenance

But excess protein can lead to:

• It increases urine output and stall ammonia levels
• May contribute to dehydration during intense exercise
• In endurance horses, heat increment from metabolizing excess protein may impair performance (Garlinghouse, 2001)

❗ Digestibility matters:

While alfalfa contains lysine, only ~21% of its protein is digested in the small intestine — the portion that matters most for growing horses (Gibbs & Potter, 2001). Complementary feeds like soybean meal, which have higher small-intestinal digestibility (~69%), may be needed to ensure adequate absorbable amino acids.

The Calcium-Phosphorus Imbalance

Alfalfa has a Ca:P ratio of around 5:1 , whereas horses require around 2:1.

Too much calcium, especially in growing horses, can cause:

• Developmental orthopedic diseases in foals (DOD)
• Poor phosphorus absorption

🔧 Fix the imbalance by:

• Add phosphorus-rich grains or supplements (like rice bran)
• Combine with grass hay to dilute the calcium load
• Use a ration balancer to restore macro-mineral ratios

Alfalfa and Developmental Orthopedic Disease (DOD)

Excessive energy — not protein or calcium alone — is the primary dietary risk factor for DOD (McIlwraith, 2001). Overfeeding alfalfa (especially alongside grain) can lead to rapid growth spurts and orthopedic problems.

That said, high-quality protein and lysine are essential for proper bone and tissue development — but it must be bioavailable, and balanced with energy and minerals.

Enterolith Risk: A Regional Caution

Feeding >50% alfalfa hay has been linked to enterolith formation, particularly in:

• Horses in California, Arizona, and other regions with hard water
• Horses kept in confinement with reduced gut motility

Struvite stones form from magnesium, phosphate, and ammonia, all of which are found in high levels in alfalfa.

📌 Prevention tips:

• Feed a mix of hays
• Add apple cider vinegar (¼ cup/day) to acidify gut contents
• Promote movement and avoid 100% alfalfa diets

Gut Fill and Boredom

Idle horses have low nutrient needs but still require bulk (fiber) for digestive health and mental stimulation.

Feeding too little alfalfa to meet their energy needs can result in:

• Frustration and wood chewing
• Pica (eating manure, hair, or dirt)
• Colic or ulcers from insufficient chewing and saliva production

Combine alfalfa with lower-calorie, coarse grass hay to provide chew time and gut fill.

Best Practices for Feeding Alfalfa

✅ Weigh your hay — don’t guess by flake

✅ Start gradually to avoid digestive upset

✅ Feed with grass hay to improve mineral balance and gut fill

✅ Use a ration balancer or grain with added phosphorus for young horses

✅ Avoid 100% alfalfa diets for horses in low work

🔄 Feeding alfalfa before riding can help buffer stomach acid and reduce the risk of ulcers, especially in performance horses.

Conclusion: Should You Feed Alfalfa to Your Horse?

Yes — if it fits your horse’s individual needs.

Alfalfa offers exceptional nutritional value for performance, reproduction, and growth — but its richness can be excessive for idle or overweight horses. Use it strategically in your feeding program, and when in doubt, consult with a vet or equine nutritionist to optimize your horse’s diet.

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