Lowering the calcium (Ca) and phosphorus (P) levels in the feed when formulating with 1000 FTU/kg OptiPhos® Plus to obtain grower and finisher feed without added monocalcium phosphate (MCP) has a positive impact on performance. Lowering the Ca levels improves P digestibility and is therefore a useful tool for optimising the efficiency of the phytase and reducing the level of inorganic P in the feed.