By Oliver Milman / theguardian.com
Feeding seaweed to cows is a viable long-term method to reduce the emission of planet-heating gases from their burps and flatulence, scientists have found.
Researchers who put a small amount of seaweed into the feed of cattle over the course of five months found that the new diet caused the bovines to belch out 82% less methane, a potent greenhouse gas, into the atmosphere.
The finding builds on previous research that showed that seaweed could reduce cows’ methane output over a shorter timespan. “We now have sound evidence that seaweed in cattle diet is effective at reducing greenhouse gases and that the efficacy does not diminish over time,” said Ermias Kebreab, director of the World Food Center and an agricultural scientist at University of California, Davis.
Cows produce methane via microbes in their stomachs as they digest their fibrous food, in a process a little like fermentation. Methane is shorter-lived in the atmosphere than carbon dioxide but is more than 30 times as effective in trapping heat, making it a major greenhouse gas. A type of seaweed called Asparagopsis taxiformis can partially counteract these emissions from cows.