The following studies were designed in an effort to help improve the efficiency and subsequently the profitability of the cattle enterprises located in the Southeastern United States through trace mineral, energy and protein supplementation, and feeding in dry lot prior to grazing. Copper (Cu) proteinate supplementation of calves grazing cool-season annual pasture prior to shipping to feedlot tended to increase gains by 4kg, while supplementation after arrival at the feedlot had no effect on weight but increased serum Cu concentrations. Supplemental Se fed to lactating beef cows increased blood Se and glutathione peroxidase activity of their calves at weaning. Feeding supplemental Se yeast to cows increased some aspects of immune function of weaned beef calves compared to feeding no Se or sodium selenite. The effect of supplementation and supplement type (energy or undegradable intake protein supplements) on performance of calves grazing stockpiled tall fescue was also studied. Calves grazing high quality fescue (22 to 26% crude protein and 67 to 80% digestible organic matter) benefited equally from a corn based supplement and supplements supplying 122 or 246 g escape protein daily, indicating that a deficiency in metabolizable protein can be cured by supplementing with rumen degradable energy or undegradable protein. The effect of dry lot diet before grazing (hay, pasture, or programmed-fed high-concentrate diets) on growth and ruminal metabolism of beef calves and reproduction of beef heifers indicate that programmed-feeding high concentrate diets is an economical alternative to feeding hay when pasture is unavailable. Age and weight at puberty and pregnancy rate of heifers that grazed cool-season annuals, were fed hay, or were programmed-fed were similar. Cost of gain of growing calves was cheaper in dry lot prior to grazing with programmed-feeding compared to feeding hay, while performance during the first 14 or 30 days of grazing was higher for calves that were programmed-fed in dry lot compared to calves that were fed hay. Ruminal pH and VFA analysis indicates variable fermentation patterns in calves across all dry lot treatments between day 9 and 23 of grazing explaining an observed reduction in forage digestibility on these days.