Caroline González-Vega is a Ph.D. candidate in the Stein Monogastric Nutrition Lab. She describes an experiment to determine the effect of microbial phytase on the standardized total tract digestibility of calcium in monocalcium phosphate, dicalcium phosphate, calcium carbonate, L. calcareum calcium, and sugar beet coproduct fed to growing pigs. Adapted from a presentation at the 2014 ASAS Midwestern Section meeting, Des Moines, IA, March 17-19.