Livestock accounts for 14.5% of all global greenhouse gas emissions, a major contributor to climate change.
Efforts to cut these emissions have received heavy criticism, with consumers raising concerns over animal welfare and the potential health impact on humans.
And just this week, Danish multinational Arla Foods faced serious backlash over the use of cattle-feed supplement Bovaer to reduce methane emissions from its cattle.
So, could a natural supplement be the solution?
Could seaweed reduce methane emissions in cows?
Researchers at the University of California Davis have discovered that a seaweed-based supplement could reduce methane emissions from grazing beef cattle by nearly 40%, without impacting the health or weight of the animal. This is slightly lower than the up-to 45% methane-reducing effects of Bovaer.
This new study is the first to examine the effects of seaweed on grazing beef cattle, and builds on earlier research conducted by the team, which demonstrated that seaweed could cut methane emissions by 82% in feedlot cattle and more than 50% in dairy cows. This is significantly higher than the 30% methane-reducing effects of Bovaer on dairy cows.
The priority for the team now is to make the seaweed supplement scalable, so it’s widely accessible to farmers.
“Beef cattle spend only about three months in feedlots and spend most of their lives grazing on pasture and producing methane,” said Professor Ermias Kebreab, senior author of the study. “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.”
How the study was conducted
The research team divided 24 beef steers (a mix of Angus and Wagyu breeds) into two groups. One group received the seaweed supplement and the other did not. The researchers conducted the study at a ranch in Montana, over a 10-week period. As the study cattle were grazing cattle, they ate the supplement voluntarily, not as part of daily feed.
However, despite the voluntary nature of the study, the seaweed supplement still produced a nearly 40% cut in emissions. This makes the prospect of administering the supplement much easier for farmers.
“This method paves the way to make a seaweed supplement easily available to grazing animals,” said Professor Kebreab. “Ranchers could even introduce the seaweed through a lick block for their cattle.”
Source: Mitigating methane emissions in grazing beef cattle with a seaweed-based feed additive: Implications for climate-smart agriculture
Published online: 2 December 2024
DOI: 10.1073/pnas.2410863121
Authors: Paulo Meo-Filho, John F Ramirez-Agudelo and Ermias Kebreab
