A recent report from the Food and Agriculture Organization (Steinfeld et al., 2006) concludes that livestock are responsible for 18% of global anthropogenic greenhouse gas (GHG) emissions. This statistic needs to be applied in the correct context and is not representative of US agriculture. Deforestation for pasture and cropland is a major contributor to global carbon dioxide emissions and has been exacerbated by the use of formerly food-producing agricultural land to grow biofuel crops (Sawyer, 2008). However, the majority of US feedstuffs are produced domestically, with increased crop yields compensating for a reduction in available cropland. Furthermore, the global figure of the FAO includes a significant contribution from extensive livestock systems producing meat or milk at very low efficiencies, thus considerably inflating the GHG output per unit of food. The effect of improved agricultural production efficiency is reinforced by figures from the US Environmental Protection Agency (US EPA, 2008) estimating that only 6.4% (454 teragrams CO2-equivalents) of national GHG emissions arise from agriculture. Dairy production is only responsible for 11.5% (52 teragrams CO2-equivalents) of this figure, resulting in a total contribution of