Pictured: Beef steers graze on a ranch in Dillon, Montana. The machine nearby releases a seaweed supplement while also measuring the cattle’s methane emissions. (Image credit: Paulo de Méo Filho / UC Davis)
Seaweed could make cattle farming more sustainable, according to new research from The University of California, Davis. The study found that feeding seaweed to grazing beef cattle in pellet form reduced their methane emissions by around 40% without negatively impacting their health or weight. The research builds on previous studies showing that seaweed cuts methane emissions caused by cows, which contribute around 33% of U.S. agriculture and 3% of total U.S. greenhouse gas emissions, by 82% in feedlot cattle and more than 50% in dairy cows.
The latest study is the first in the world to test seaweed on grazing beef cattle. Due to their fiber-rich grass diet, these cattle produce more methane than feedlot cattle or dairy cows. In the U.S., there are around nine million dairy cows and more than 64 million beef cattle.
Explaining the significance of the findings, senior author Ermias Kebreab, professor in the Department of Animal Science, said, “Beef cattle spend only about three months in feedlots and spend most of their lives grazing on pasture and producing methane. We need to make this seaweed additive or any feed additive more accessible to grazing cattle to make cattle farming more sustainable while meeting the global demand for meat.”
Researchers conducted a 10-week experiment with 24 beef steers, which they divided into two groups: one received the seaweed supplement, and the other did not. Since these were grazing cattle, they ate the supplement voluntarily, which still resulted in a nearly 40% cut in emissions.
“This method paves the way to make a seaweed supplement easily available to grazing animals,” said Kebreab. “Ranchers could even introduce the seaweed through a lick block for their cattle.”