The objectives of this study were to estimate the number of idle cattle, water buffalo, and swine globally and evaluate their impact on feed and water resource utilization as part of the larger Food Forward Sustainability Project. The term “idle” is defined as an animal that is not growing, pregnant, lactating, held for breeding, or used for draft. Two data sources were used: 1) USDA Foreign Ag Service data that includes cattle and swine inventories for 19 countries, and 2) FAO data that includes inventories of cattle, water buffalo, and swine for 16 sub-continental regions. A gamma distribution was used to estimate survival and the number of non-breeding animals alive after 4, 5, and 1 years for cattle, water buffalo, and swine, respectively. Non-breeding stocks were adjusted for imports and exports. Turnover age was calculated as stock numbers divided by slaughter numbers and represents the average lifespan of an animal in the non-breeding population in steady state conditions. Feed consumption estimates were cross-validated using maintenance energy requirements and found to be in reasonable agreement. Turnover ages ranged from 2.6 to 14.7 years for cattle, 3.0 to 8.5 years for water buffalo, and 4.8 to 21.1 mo for swine across regions. It was estimated that 46.6 ± 0.6% of 1.45 billion cattle, 61.1 ± 0.5% of 190 million buffalo, and 9.8 ± 0.3% of 946 million swine in the world in 2010 were mature, non-breeding animals. With cattle and water buffalo, a portion of these animals may be maintained for draft purposes and would not be completely idle. At this time, no data are available to reliably estimate the draft use of cattle and water buffalo. Also, in some societies, mature animals may be maintained as a form of personal wealth, defense against times of food scarcity, or both. Idle and draft cattle, water buffalo, and swine consumed an estimated 1068, 132, and 62 million metric tons of feed (DM basis) or 44% of total feed required, and 2840, 364, and 154 billion liters of water, respectively, in 2010. Reducing the number of idle cattle, water buffalo, and swine is one of several viable options to increase system-wide production efficiency and decrease the total amount of resources required to produce animal-based foods.