Led by Professor of Aquaculture Rocky De Nys, researchers found an addition of less than 2 percent dried seaweed to a cow’s diet can reduce methane emissions by 99 percent. The study was conducted in collaboration with the Commonwealth Scientific and Industrial Research Organization (CSIRO), an Australian federal research agency.
Methane is about 25-times more potent than carbon dioxide in a 100-year time span, and a single cow releases between 70 and 120 kilograms of methane per year. Burps from cows account for 26 percent of the United States’ total methane emissions, and the U.S. is only the world’s fourth-largest producer of cattle, behind China, Brazil, and India. There are currently approximately 1.3 to 1.5 billion cows roaming the planet.
Researchers started investigating the potential effect of seaweed on cows in 2005, when a dairy farmer named Joe Dorgan inadvertently conducted an experiment on his herd in Prince Edward Island, Canada. Dorgan noticed cows that grazed on washed-up seaweed in paddocks along the shore were healthier and more productive than those that stayed in the field. He began feeding his cows a mixture of local storm-tossed seaweed and found the new diet saved him money and induced “rip-roaring heats,” or longer cycles of reproductive activity.