Low‑Carb Diets for Horses: Expert Equine Vet Guide 2025
In this article
Low‑Carb Diets for Horses: Expert Equine Vet Guide 2025 🐴
By Dr Duncan Houston
Introduction 🌱
If you have a horse that is overweight or dealing with equine metabolic syndrome, you’ve likely heard about low‑carb diets. In this guide, Dr Duncan Houston explains why the type of carbohydrate matters, the risks of feeding rich pasture, and how to build a safe, effective nutrition plan.
1. Carbohydrates in Horse Nutrition: A Vet’s Perspective
All horses need carbohydrates for energy—but not all carbs are created equal. Here’s how Dr Duncan Houston breaks it down:
- Simple carbs: Starches and sugars like glucose—digested in the small intestine, can spike insulin and trigger laminitis.
- Complex carbs: Cellulose, hemicellulose, pectins, lignin—broken down slowly by hindgut bacteria, low impact on insulin.
Understanding this difference is key to managing conditions like laminitis, founder, and equine metabolic syndrome.
2. Non‑Structural Carbohydrates (NSC): Hidden Risks in Forage
Even “healthy” hays and pastures contain non‑structural carbs (NSC)—the starches and sugars that stimulate insulin. Research from Sacramento-based equine experts emphasizes that:
- Lush spring pasture is especially high in NSC.
- NSC content varies with season, weather, cutting time, and storage.
Dr Duncan Houston recommends testing hay and pasture for NSC percentage and aiming for below 10–12% NSC in the total diet for metabolic horses.
3. Common Misconceptions About Grain vs. Pasture
It's a myth that only grain causes laminitis. In fact, the largest number of cases stem from grass overload. Here’s why:
- Excessive grain ingestion can trigger laminitis—but it's rare.
- The *real* culprit for many overweight or metabolic horses? Overconsumption of simple sugars from green pasture in spring.
Thus, metabolic horses must avoid lush pasture—even if no grain is fed.
4. Practical Management: Hay, Dry‑Lot, and Grazing Strategies
Dr Duncan Houston outlines a management plan:
- Dry‑lot turnout: Provide a fenced area with minimal or no grass.
- Low‑starch hay: Offer tested hay under 10–12% NSC—alfalfa mix or mature grass hay often works.
- Low‑starch grain (if needed): Choose feeds specially formulated for metabolic horses.
- Grazing muzzle: Reduces pasture intake by 60–70%—useful when total turnout is desired.
This approach helps maintain natural movement and social interaction, while controlling sugar intake.
5. Monitoring Your Horse: Body Condition, Weight, and Metabolic Parameters
Regular monitoring is essential. Dr Duncan Houston suggests:
- Monthly body condition scoring using a 1–9 scale.
- Weighing at regular intervals (e.g., monthly) via weigh‑tape or scale.
- Periodic bloodwork to track insulin, glucose, and leptin levels.
Adjust feed intake based on trends—reduce by ~10–20% if BCS stalls or rises.
6. Case Scenarios & Success Stories
Case A: Overweight Pony with EMS 🐴➡️🏃♂️
A 15‑year‑old pony showed BCS of 7/9 and mild laminitis. After switching to dry‑lot, low‑NSC hay, a grazing muzzle, and light exercise, the pony’s BCS dropped to 5/9 in 16 weeks, and insulin stabilized.
Case B: Managing Lush Spring Grass
A gelding prone to laminitis was protected from fresh grass by staying in a dry‑lot during April–June, then reintroduced in small pasture with grazing muzzle. No laminitis recurred.
7. Exercise, Supplements & Long‑Term Care
Dr Duncan Houston emphasizes the synergy of diet and exercise:
- Regular low‑impact exercise: 20–30 min walks or trot after turnout.
- Supplements: Magnesium, chromium, and omega‑3s may support insulin sensitivity—discussed with your vet.
- Regular hoof care: Visit farrier every 6–8 weeks to monitor for founder changes.
8. Feeding Guidelines Summary
| Diet Component | Target NSC | Notes |
|---|---|---|
| Hay (mature grass/alfalfa mix) | <10–12% | Test before purchase |
| Pasture | Limited (dry‑lot/muzzle) | Lush spring = high risk |
| Grains/Concentrates | Low‑starch | Only if energy shortfall |
9. Common Questions from Horse Owners
Q: Can they ever graze spring grass?
A: No—not without a grazing muzzle and short durations. Spring grass often exceeds 15–30% NSC and poses laminitis risk.
Q: What about hay soaking?
A: Soaking hay for 30–60 min can reduce soluble sugars by 10–20%, useful when hay NSC is borderline.
Q: Is alfalfa safe?
A: Yes—alfalfa is typically low in NSC but may be higher in protein and calcium—balance with your vet.
10. Final Takeaways from Your Equine Vet
- NSC control is crucial—test hay and manage pasture.
- Dry‑lot + low‑starch hay + muzzle = metabolic safety.
- Month‑by‑month tracking ensures progress.
- Diet, exercise & hoof care together protect against laminitis.
By following these evidence‑based vet strategies, you'll help your horse thrive and reduce metabolic risks.
Conclusion & Next Steps
Struggling with your horse’s weight or metabolic health? Reach out to Ask A Vet for expert guidance. Download the Ask A Vet app for personalized diet plans, NSC hay testing, and 24/7 vet support. Your horse deserves a healthy, happy life—let’s work together! 🐴❤️
