Researchers have been searching for ways to reduce cattle emissions with food additives, such as garlic, oregano, cinnamon and even curry — with mixed results. Dairy farms and other livestock operations are a major source of methane, a heat-trapping gas, much more potent than carbon dioxide. Both gases contribute to global warming. Now, University of California researchers are feeding seaweed to dairy cows in an attempt to make cattle more climate friendly. VOA’s Deborah Block has the story. …