Selenium

Selenium is an essential trace mineral required in equine nutrition for its role in antioxidant defense, immune function, and thyroid hormone metabolism. It is a key component of glutathione peroxidase, an enzyme that helps protect cells from oxidative damage by neutralizing free radicals. Selenium also plays a role in muscle function and overall metabolic health.

Horses can obtain selenium from forages, but its content varies depending on soil selenium levels in different regions. In areas with selenium-deficient soils, supplementation is necessary to prevent deficiencies, which can lead to conditions such as white muscle disease, impaired immune function, and poor reproductive health. Selenium is commonly supplemented in the form of sodium selenite, sodium selenate, or organic selenium sources such as selenium yeast, which is considered more bioavailable.

Because selenium has a narrow margin of safety, excessive intake can lead to toxicity, characterized by symptoms such as hair loss, hoof abnormalities, and neurological issues. Proper formulation and monitoring of selenium intake are essential to ensure optimal health in horses.