California annual rangeland pasture is generally poor in the fall and in short supply during winter. To correct deficiencies and maintain acceptable performance, ranchers usually provide supplemental nutrients to the range beef cow herd during the later part of the dry forage season (July to October) and the inadequate green forage season (October to January). Low profit margins, rising costs of supplemental feed and labor, and other expenses involved in distribution make the decision to supplement an important one.