NRG’s Calcium has added Magnesium and Selenium for high absorption and the correct balance of Phosphorous to combat feed imbalance. The NRG Calcium mix has the ideal balance of Calcium and Phosphorous at a 2:1 ratio with added Magnesium for better Calcium absorption and Selenium for muscle development. Many horses’ diets tend to be Calcium deficient and extra Calcium is required to balance the Ca/Ph ratio.