Equine Products UK Cal-Phos - Calcium And Phosphorus Feed AdditiveCALCIUM & PHOSPHORUS FEED ADDITIVE Calcium and phosphorous are two of the most important macro minerals in terms of quantity required by horses, but it is the ratio of these elements which is crucial. This is particularly important where horses are fed a diet with high grain intake as grains can have a ratio of phosphorous to calcium as high as 6 to 1. Calcium is essential for development of strong bones. Regular feeding of Cal Phos can assist in the