Busting the Breed-Specific Diet Myth
By Annie Emery
Are there breed-specific diets for horses? Is there a special Mustang diet? A unique Lusitano diet? Let's set the record straight using what we know about horses, the National Research Council; (NRC) and feeding fundamentals
Breed Specific Diets: Social Media Myth?
Many claim that mustangs have developed a unique digestive system due to being wild ... .they can simply graze on hay without concentrates or even minerals. Others argue that Spanish horses, like Lusitanos, need a special diet because of a unique metabolism. Unfortunately, this misinformation does more harm than good and creates a lot of unnecessary stress and confusion in the equine community
The fact is, while every horse is unique in temperament and body condition, their digestive anatomy and physiology are fundamentally the same. Whether your horse is a Mustang, a Lusitano, or any other breed, the basic nutritional requirements are backed by science.
Forage Is Key!
We know that a horse’s hindgut is designed to ferment long-stemmed hay and grasses, producing volatile fatty acids that fuel their energy needs. Forage—defined as long-stem hay and long-stem grasses—is the cornerstone of every equine diet. Hay is always first choice….Pelleted feeds can complement, but should never replace, quality forage. (Please see the other resources for more about why this is the case). There is still a persistent myth floating out there that hay alone will meet horses’ needs and is more “NATURAL”
Based on National Research Council (NRC) guidelines, even mustangs need more than hay alone to meet their full nutritional requirements. See my other article about this for an in-depth review.
No matter the breed—be it a mustang, quarter horse, paint, or any other—the numbers don’t lie. Hay by itself cannot provide all the nutrients a horse needs, and relying solely on a mineral block isn’t sufficient either. We ran the numbers personally and have seen hundreds of horses for nutrition evaluations- this is just a fact especially when many hays are not as nutritionally dense as we hope!
Beyond Breed: Focus on Individual Needs
There is no “magic” or specialized feed formula that caters to a specific breed’s supposed unique metabolism. Instead, successful feeding programs consider:
Life Stage & Workload: A growing foal, a working adult, and an aging horse all have different needs.
Body Condition: Whether your horse is an easy keeper or a hard keeper, adjustments should be made to maintain a healthy weight.
Environment & History: The diet may vary based on climate, pasture availability, and the horse’s previous nutrition.
I’ve worked with mustangs that are underweight and others that are overweight. The takeaway? Always strive to keep your horse at a healthy weight with a balanced diet, regardless of breed.
Addressing the Myths
Myth #1: Mustangs Can Thrive on Hay Alone
Mustangs, though often viewed as “thrifty” and wild, still require more than just hay. Feeding them solely on hay can lead to nutritional deficiencies and potential health issues.
Myth #2: Spanish Horses Have a Special Metabolism
The idea that Lusitanos need a “special” diet is not supported by science. While some breeds may have a predisposition to metabolic disorders, the key is to monitor their body condition and work closely with your veterinarian—not to chase a myth of unique digestive enzymes.
Consistency Is Key
Variety in a diet sounds appealing—wild horses might naturally graze on various forages—but don’t be tempted to switch between five different hay types or throw in random concentrates day to day. This really affects their sensitive systems! Abrupt changes can disrupt the delicate balance of hindgut microbes, leading to colic, diarrhea, or worse. We like to stick to a plan! If you’re using a mix of forages, keep it consistent. Enrichment is great, but not at the cost of digestive upset.
Practical Takeaways
Forage First: Always base your horse’s diet on high-quality long-stem hay.
Monitor and Adapt: Keep an eye on body condition, workload, and any signs of metabolic issues.
Get Help: Owners aren’t expected to know this for themselves! Reach out for help
Final Thoughts
There is no breed-specific diet that magically caters to mustangs, Lusitanos, or any other type of horse. All horses share the same fundamental nutritional needs, and a balanced, forage-based diet remains the best approach. Whether you're transitioning a wild Mustang into a domestic setting or managing the dietary needs of a predisposed breed, the principles of good nutrition remain constant.
This post is for informational purposes only and reflects the author’s opinions. No part may be reproduced without permission. Use at your own risk. This content is not a substitute for professional advice regarding your horse’s health or nutrition. Always consult a qualified equine professional before making changes to your horse’s care. The author is not liable for any damages or losses from using this information. Copyright 2025 Revolution Equine Nutrition, LLC