Vitamin E Loss in Hay: What Every Horse Owner Should Know

Vitamin E is one of the most essential antioxidants in the equine diet, supporting muscle comfort, nerve function, and a strong immune system. Horses are designed to obtain Vitamin E from fresh, green pasture — but when forage is harvested and dried as hay, something important changes.

Hay Loses Vitamin E Quickly After Cutting

Research from the University of California, Davis shows that once forage is cut, cured, and stored as hay, its natural Vitamin E (α-tocopherol) levels begin to decline rapidly. Multiple studies have documented that hay can lose around 50% of its Vitamin E within the first month of storage, depending on temperature, sunlight exposure, and moisture conditions. In extended storage—especially under warmer or sun-exposed conditions—broader forage-science research shows total losses that can approach 70–80% over time.

In other words: even high-quality hay may not supply anywhere near the same Vitamin E levels your horse would receive from pasture.

Why Low Vitamin E Matters

Horses relying primarily on hay — especially in winter, dry climates, or dry-lot management — may fall short in Vitamin E. Low levels are associated with:

• Muscle discomfort or stiffness
• Poor post-exercise recovery
• Neuromuscular concerns, including lower serum α-tocopherol levels
• Reduced immune resilience during stress, travel, or seasonal changes

UC Davis researchers have documented that horses with restricted pasture access consistently show lower Vitamin E status and may require dietary support to maintain optimal health.

Not All Vitamin E Is Absorbed Equally

University and peer-review studies show that the natural form of Vitamin E (d-alpha-tocopherol or d-alpha-tocopheryl acetate) is absorbed and utilized 2–3× more efficiently than synthetic Vitamin E (dl-alpha-tocopherol).

This means horses get more benefit from the same dose when the natural form is used — an important detail when correcting low levels.

Daily Natural Vitamin E: Designed for Hay-Fed Horses

Daily Natural Vitamin E from Equine Balanced Support is formulated using the natural d-alpha acetate form shown to be superior in absorption. Delivered as a stable, palatable powder, it provides reliable support for horses who:

• Are on hay-only or winter diets
• Have limited or no access to fresh pasture
• Need muscle, nerve, or immune support
• Are in training, travel, or rehabilitation

When hay can’t provide what nature intended, Daily Natural Vitamin E helps ensure your horse gets the antioxidant support they depend on.