Description Of Union Food Ingredient Monocalcium Phosphate (MCP) CAS No. 7758-23-8: (MCP) Monocalcium Phosphate - defluorinated feed phosphate is used as a feed supplement for livestock and poultry. Monocalcium phosphate acts as a restorative to the mineral deficiency (phosphorous and calcium) in the diet of cattle. They facilitate the metabolism of livestock and poultry, strengthening their immune and reproductive system.