Effects of barley starch:NDF ratio and DDGS inclusion on feedlot performance, carcass characteristics, and N and P mass balance were evaluated in a commercial feedyard in Alberta, Canada. Yearling heifers were assigned randomly at reimplant to four treatments (0 or 20% DDGS and LOW or HIGH starch:NDF barley). Feeding LOW starch:NDF barley improved feedlot performance and increased N retention. Feeding 20% DDGS increased DMI, had a slight negative impact on F:G, and increased N and P losses