Greenhouse gas emissions from simulated beef and dairy livestock systems in the United States

Computer spreadsheets were developed to evaluate greenhouse gas (GHG) emiss ions from U.S. beef and dairy livestock systems from nine locations. Of the beef systems the cow-calf herd emitted the most and feedlot cattle the lea st methane (CH4) and nitrous oxide (N2O) per unit product. Carbon dioxide ( CO2) emissions per unit product were the least for the cow-calf and greates t for the feedlot scenarios. In the dairy systems approximately one-half of the total GHG CO2 equivalents were from CH4 and one-third from N2O. Mitiga tion strategies, such as intensive grazing, reduced GHG emissions by approx imately 10%.