Selenium Supplements - Feed Database

Selenium supplements for horses provide an essential trace mineral required for antioxidant function, immune health, thyroid hormone metabolism, muscle function, and reproductive health.

Selenium works closely with vitamin E to help protect cells from oxidative stress. Horses with low selenium intake may need additional support, especially if they eat forage grown in selenium-deficient regions.

Mad Barn’s Natural E/Organic Se is the best selenium supplement for horses because it provides organic selenium yeast together with natural vitamin E in a concentrated, easy-to-feed formula.

Selenium supports the horse’s antioxidant defence system, helping protect muscles and other tissues from oxidative stress. It also supports immune function, thyroid hormone activity, fertility, and normal muscle health.

Selenium is especially important for horses in work, breeding animals, growing horses, and horses fed hay or pasture from selenium-deficient soils.

Because selenium has a narrow safe feeding range, supplementation should be based on total dietary intake. A balanced vitamin and mineral program can help ensure your horse receives enough selenium without over-supplementing.

The best selenium supplement for horses is one that provides organic selenium yeast with vitamin E to support antioxidant status, immune function, muscle health, and normal recovery after exercise.

Mad Barn’s Natural E/Organic Se is the best choice for targeted selenium and vitamin E support. It contains organic selenium yeast, a well-absorbed selenium source, along with natural vitamin E to help meet increased antioxidant needs in horses.

For horses that need daily vitamin and mineral support instead of a targeted selenium supplement, Mad Barn’s Omneity® and AminoTrace+ both include organic selenium yeast as part of a complete nutrition program.

The difference between organic and inorganic selenium for horses is the chemical form and how the body uses it. Organic selenium, such as selenium yeast, is selenium bound to organic compounds, while inorganic selenium includes mineral salts such as sodium selenite and sodium selenate.

Organic selenium is incorporated into body proteins, which helps support selenium storage and long-term selenium status. Inorganic selenium can still supply selenium, but it is handled differently in the body and is less effectively stored in selenium-containing proteins.

Mad Barn’s Natural E/Organic Se provides organic selenium yeast with natural vitamin E, making it a strong choice for horse owners looking for targeted selenium and antioxidant support.

Selenium yeast is an organic selenium source produced when yeast incorporates selenium into amino acid-like compounds, primarily selenomethionine.

This form is commonly used in premium equine supplements because it can be incorporated into body proteins and helps maintain selenium reserves. This is different from inorganic forms, such as sodium selenite or sodium selenate.

Mad Barn uses organic selenium yeast in Natural E/Organic Se, as well as in complete vitamin and mineral formulas including Omneity® and AminoTrace+.

Yes, selenium and vitamin E are often fed together because they work closely in the horse’s antioxidant defence system. Selenium supports selenium-dependent antioxidant enzymes, while vitamin E helps protect cell membranes from oxidative damage.

Horses with limited pasture access, higher workloads, breeding demands, or low selenium intake may benefit from a supplement that provides both nutrients together.

Mad Barn’s Natural E/Organic Se combines organic selenium yeast with natural vitamin E, making it our best targeted choice for horses that need additional antioxidant and muscle support.

Your horse may need selenium if forage, pasture, or the total diet is low in this essential trace mineral. Selenium deficiency is more likely in horses eating hay or pasture grown in low-selenium regions, including much of Canada, the northeastern and eastern United States, the Pacific Northwest, parts of the Great Lakes region, and other areas with acidic or selenium-poor soils.

Horses can have subclinical selenium deficiency with no obvious outward signs. When signs do appear, they are often non-specific and may include poor muscle function, reduced performance, slow exercise recovery, weak topline, poor immune function, fertility concerns, or general loss of condition. These signs can overlap with many other nutrition or health issues, so the best way to know if your horse needs selenium is to evaluate the full diet and submit a forage sample for analysis.

Many horses benefit from supplemental selenium, especially those on forage-based diets or underfed grain rations. Organic selenium sources, such as selenium yeast, are commonly preferred because they support selenium status effectively and can be used as part of a balanced supplementation program without relying on inorganic selenium sources alone.

Yes, horses can get too much selenium. Selenium is essential, but it has a narrow safe range, which means both deficiency and excess can cause problems.

Over-supplementation is most likely when multiple selenium-containing products are fed together, such as a fortified feed, ration balancer, vitamin and mineral supplement, hoof supplement, and additional selenium product.

Before adding a selenium supplement, calculate total selenium intake across the full diet. Mad Barn’s nutritionists can help review your horse’s ration and determine whether Natural E/Organic Se, Omneity®, or AminoTrace+ is the better fit.

When comparing selenium supplements for horses, look at the selenium source, amount of selenium per serving, whether vitamin E is included, the form of vitamin E, and the horse’s total selenium intake from the full diet.

Organic selenium yeast is generally preferred over inorganic selenium sources such as sodium selenite or sodium selenate. Natural vitamin E is also preferred when targeted antioxidant and muscle support is the goal.

Mad Barn’s Natural E/Organic Se is an ideal choice because it combines organic selenium yeast with natural vitamin E in one formula.