Methane Emissions from livestock
   A few facts about animal emissions.
   http://www.ciesin.org/TG/AG/liverear.html

Ruminant Livestock Efficiency Program - US EPA
   Ruminant livestock such as cattle and sheep are the largest source of methane emissions resulting from human activity. Methane is a potent greenhouse gas. RLEP is a joint EPA-USDA program helping livestock producers improve their operations' efficienc
   http://www.epa.gov/rlep/