Australian research shows seaweed extract reduces methane in grazing cows safely
According to the research conducted by Adelaide University, researchers have shown that a natural compound made from red seaweed can greatly reduce methane emissions from beef cattle raised on open pastures. The study focused on pregnant and lactating beef cows managed under real farm grazing conditions.
Methane is a powerful greenhouse gas that contributes significantly to global warming. Reducing methane from livestock is difficult in grazing systems because animals move freely, and their feed intake is harder to control compared to feedlots.
The researchers tested a bromoform-based oil extracted from the seaweed Asparagopsis. The supplement was provided to Angus cows over an eight-week period. Results showed methane emissions dropped between 49% and 77% in supplemented cows.
"This is critical," said Lead researcher Dr. Mariana Caetano, from the School of Animal and Veterinary Sciences. "In breeding systems, it's not just about the cow—you need to be confident there are no unintended consequences for their offspring."
Importantly, the study found no negative effects on animal performance. Cows maintained stable body weight even though their feed intake slightly decreased. This may help farmers reduce feed costs without losing productivity.
Calves born to treated cows grew normally from birth to 150 days of age. Their weight gain and development remained within healthy ranges, showing no harmful effects from the maternal supplement.
Some minor changes were seen in cow and calf blood chemistry, including higher alkaline levels in a few animals. However, all values stayed within acceptable health ranges. Researchers noted that further long-term studies are needed to confirm full safety.
Previous methane reduction studies mainly focused on feedlots. This research shows that the supplement also works in large-scale grazing systems, which are common in beef-producing countries.
Scientists believe this seaweed-based approach could help farmers lower emissions while maintaining animal health and farm profitability. Future work will focus on improving delivery methods, refining dosage, and ensuring the solution is cost-effective.
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