Bovine and caprine Monterey Jack cheeses were produced unfortified (cheese) or fortified with milk calcium (Ca-cheese). Five groups of male rats were fed a control diet or one of four experimental diets: bovine cheese diet, bovine Ca-cheese diet, caprine cheese diet, and caprine Ca-cheese diet to test their effects on calcium absorption as well as bone mineralization. Significant differences (P < 0.05) were found for calcium absorption and digestibility with the data yielding the pattern: caprine Ca-cheese>caprine cheese=bovine Ca-cheese>bovine cheese>control. Significant increases (P < 0.05) occurred in bone mineral content (BMC), bone mineral density (BMD) and breaking force in the femoral bone with the pattern: caprine Ca-cheese>caprine cheese>bovine Ca-cheese>bovine cheese>control. Our findings suggest that caprine cheese unfortified or fortified with milk calcium had the most positive effects on calcium absorption and bone mineralization in rats, with bovine cheeses still having significantly greater effects than the non-casein control. © 2006 Elsevier Ltd. All rights reserved.