It is well known that daily supplementation is the most efficient way to administer Selenium. One 15 gram dose of Selenium K provides 1.66mg of available Selenium, this being the optimal level for an adult horse. It is an easy efficient non toxic way of ensuring correct selenium levels. Broodmares should also receive Selenium K in the breeding season as it is known to help increase fertility.Equine Selenium K is in a Kelp base. Kelp meal is a natural feed supplement derived from a seaweed found only in the North Atlantic Ocean. Rich in micronutrients; it contains over 30 minerals including Boron, Molybdenum, Iodine, Sulphur and Iron, 12 Vitamins, 18 Amino Acids as well as high levels of Alginic Acid.