Walk down any feed store aisle and you’ll find shelves of vitamin and mineral supplements, each promising to cover what your horse is missing. But the right choice isn’t about the flashiest label. It’s about filling the specific gaps in your horse’s diet without adding things he doesn’t need.

The equine nutritionists at Mad Barn break down why most horses need a vitamin and mineral supplement, which nutrients come up short most often, and how to pick a product that truly balances the ration.

Why Hay Alone Usually Isn’t Enough

Forage should always be the foundation of your horse’s diet. Hay and pasture supply the fiber he needs for digestive health and usually provide most of his calories and protein.

What forage doesn’t do is consistently deliver every vitamin, mineral, and amino acid your horse needs. Nutrient content varies widely with soil type, plant species, maturity at harvest, weather, and storage. Vitamin E is a good example: Horses on fresh pasture take in far more of it than horses eating stored hay, which is why hay-fed horses often need extra antioxidant support.

Commercial feed doesn’t always close the gap, either. Many fortified feeds are designed to be fed at fairly high rates, but most horses get less than a full serving. When the feed is underfed, vitamin and mineral intake falls short, too.

That’s where a concentrated vitamin and mineral supplement earns its spot in the feed room. It lets you adjust nutrient intake independently of calories, which matters for the many horses that hold their weight without much grain but still need a complete supply of essential nutrients.

The 5 Most Common Gaps in Horse Diets

A Mad Barn analysis of more than 6,500 equine diets found these nutrients were most often lacking in forage-based and grain feeding programs:

• Sodium. An electrolyte needed for fluid balance, nerve signaling, and muscle function. Horses lose it daily in sweat, urine, and manure, so plain salt should always be provided.
• Vitamin E. A fat-soluble antioxidant that helps protect muscle and nerve cells. Levels drop significantly once forage is cut and stored.
• Selenium. Works with vitamin E to support antioxidant defense, immune function, and muscle health. Forage levels depend on the soil, so risk varies by region.
• Zinc. Important for hoof quality, skin, immune function, and enzyme activity. High dietary iron can reduce how much zinc your horse absorbs.
• Copper. Needed for connective tissue, antioxidant enzymes, and healthy hooves and coat. Like zinc, it’s harder to absorb when iron is high.

Over time, these shortfalls can show up as a dull coat, brittle feet, slow hoof growth, a poor topline, or a horse that tires easily. But deficiencies aren’t always obvious. Your horse can look healthy while he’s running low enough to affect his hoof quality, muscle development, immune function, or recovery after a hard ride.

Minimum Requirements vs. What Your Horse Needs to Thrive

Nutrient requirements for horses come from the National Research Council (NRC), which estimates daily needs based on body weight, age, growth, workload, and reproductive status. Those numbers are a useful starting point, but they’re best viewed as a minimum standard designed to prevent deficiency, not necessarily the ideal intake for long-term health and performance.

Your horse’s real-world needs are shaped by forage quality, gut health, stress, training, and his individual makeup. Biotin is a good example. There’s no official NRC requirement, yet research shows that 20 mg per day for an 1,100-pound horse can improve hoof horn quality and support hoof growth.

Mineral interactions matter, too. If your horse eats high-iron hay, he may take in enough zinc and copper on paper but still not use them efficiently. That’s why horses on high-iron forage often benefit from more targeted trace-mineral support.

What to Look for in a Vitamin and Mineral Supplement

The first question to ask is simple: Will this product actually balance my horse’s diet at the recommended feeding rate? A well-formulated supplement should cover most vitamin and mineral requirements when fed as directed. The big exception is sodium. Horses need too much salt for a concentrated supplement to deliver, so add plain loose salt to the ration (generally at least 2 tablespoons a day for an 1,100-pound horse) and offer free-choice loose salt.

Beyond the basics, look for:

• Organic trace minerals such as copper, zinc, selenium, and manganese proteinates, which are highly bioavailable
• Adequate vitamins E and A, since both degrade in stored hay
• Complete B-vitamin fortification to support energy metabolism and nervous system function
• A full serving of biotin for hoof, mane, and tail growth
• Limiting amino acids (lysine, methionine, and threonine) to support topline, hoof growth, and recovery
• No added iron, since most horses already get more than enough from forage
• Digestive support such as yeast, enzymes, or prebiotics (here’s how to choose the best gut supplement for your horse)

The product should also be nutrient-dense enough to balance a forage-based diet at a small feeding rate, without adding unnecessary sugar, starch, or calories.

Omneity®: An All-in-One Option for Most Horses

Mad Barn’s Omneity® is formulated for most horses on forage-based diets or underfed grain programs. Because it provides comprehensive nutrition in one product, many owners find they don’t need a separate hoof supplement or individual nutrients on top of it.

Omneity® comes in two formats: a loose premix fed at 120 grams a day for an 1,100-pound horse, and pellets fed at 200 grams a day. Both provide 100% organic trace minerals, complete B-vitamins, 200% of daily vitamin E requirements, research-backed levels of biotin, essential amino acids, yeast, and digestive enzymes, with no added iron and no added fillers, sugars, or molasses.

AminoTrace+: For Horses That Need More

AminoTrace+ is Mad Barn’s enhanced formula for horses with higher nutrient demands, including easy keepers, horses with metabolic concerns or a history of laminitis, horses with poor hoof quality, and horses on high-iron forage. It’s also a strong fit for hard-working performance horses that need extra support for training, travel, and recovery.

Fed at the same 200 grams a day as Omneity® Pellets, AminoTrace+ delivers higher levels of copper, zinc, magnesium, natural vitamin E, and amino acids, plus chromium and a full 20 mg of biotin. Its low-NSC formula has no added iron and includes yeast and prebiotics for hindgut support.

Which One Fits Your Horse?

Omneity® and AminoTrace+ are both complete supplements, so don’t feed them together. That would double up on vitamins and minerals. If your horse needs help with a specific concern, you can add a targeted supplement alongside either one.

Get a Free Diet Review

The best vitamin and mineral supplement is the one that corrects the gaps in your horse’s diet and fits his individual needs. Not sure where your horse stands? Submit his current feeding program to Mad Barn for a free ration review, and an equine nutritionist will identify nutrient gaps, imbalances, and the best fit for your horse.