Seaweed Supplements Significantly Reduce Livestock Greenhouse Gas Emissions

Beef cattle fed red algae showed reductions in methane emissions of over 50 percent without affecting meat quality.

Livestock farming is a major source of greenhouse gas emissions worldwide because ruminants like sheep and cattle produce methane as a byproduct of digestion. Supplementing the diet of beef cattle with red seaweed can more than halve methane emissions without compromising meat quality, according to a study, published on March 17, 2021, in the open-access journal PLOS ONE, by Breanna Roque from the University of California and colleagues.

The researchers fed twenty-one Angus-Hereford beef bullocks their usual diet of hay, grains, and corn, supplemented with either zero, low, or high concentrations of red seaweed (Asparagopsis taxiformis). They measured the quantity of methane, hydrogen, and carbon dioxide released by individual bullocks periodically for 21 weeks and found that seaweed supplements reduced methane emissions by between 45 percent and 68 percent.

The proportion of forage in the base diet also influenced emissions; the greatest reductions were found with a high seaweed-supplemented, low-forage diet, which reduced methane production by as much as 80%. Professional grading and consumer testing revealed no effect on the quality or flavor of the meat.

Efficiency Gains and Climate Benefits for Farmers

The study is the first to show a sustained reduction in cattle greenhouse gas emissions as a result of feed supplementation. Bullocks also sustained normal growth rates while consuming less food, suggesting that red seaweed supplemented diets could help farmers improve efficiency, reduce costs, and reduce methane emissions simultaneously, the authors say.

“There is more work to be done, but we are very encouraged by these results,” Roque said. “We now have a clear answer to the question of whether seaweed supplements can sustainably reduce livestock methane emissions and its long-term effectiveness.”

Read Feeding Cattle a Bit of Seaweed Reduces Their Greenhouse Gas Emissions 82% for more on this research.

Reference: “Red seaweed (Asparagopsis taxiformis) supplementation reduces enteric methane by over 80 percent in beef steers” by Breanna M. Roque, Marielena Venegas, Robert D. Kinley, Rocky de Nys, Toni L. Duarte, Xiang Yang and Ermias Kebreab, 17 March 2021, PLOS ONE.
DOI: 10.1371/journal.pone.0247820

Funding: This research received financial support from Elm Innovations, the David and Lucile Packard Foundation and the Grantham Foundation. Financial Support was only used to cover the costs of conducting the experiment only. Funders did not have a role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript.

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