Beef cattle manure collected from unpaved dirt feedlots has a significantly reduced energy production potential due to low organic content and dirt contamination. In laboratory batch fermentors beef feedlot manure of various ages was digested. The study showed that compared with fresh manure gas production at 100 percent, aged manure produced between 16 and 73 percent of the gas per kilogram of volatile solids added. More than half of the nitrogen was lost after the manure had aged 3 months. The resulting economic advantage of fresh manure over aged manure for energy and nitrogen recovery would be from $26 to $61 per head per year.