A dash of oregano does more than make pizza taste delicious: it also can reduce the amount of methane in cow burps, new research shows. Scientists have been trying to decrease methane from livestock for years; methane is over 20 times more potent than carbon dioxide (CO2) as a greenhouse gas, and cows in the U.S. emit about 5.5 million metric tons of methane per year. Scientists have tried vaccines, breeding, antibiotics, and other dietary supplements like garlic or fumaric acid (found in lichens and moss). Alexander Hristov, assistant professor of dairy nutrition at Penn State, spent six years in...