Seaweed supplements reduce methane in grazing cattle

Sustainability in cattle farming has taken a promising step forward. Researchers discovered that feeding a seaweed supplement to grazing beef cattle can reduce methane emissions by nearly 40%.

This study demonstrates that environmental benefits can align with cattle health and productivity.

Professor Ermias Kebreab, a researcher at the University of California (UC), Davis, led the team behind this study. Earlier findings showed that seaweed could cut methane emissions by 82% in feedlot cattle and over 50% in dairy cows.

Understanding cattle grazing

Cattle grazing is an important part of farming around the world. It makes use of land that can’t be used for crops, turning grass into food and other useful products.

Grazing also helps keep grasslands healthy, supports wildlife, and reduces the risk of wildfires.

The management of grazing cattle varies significantly based on geography, climate, and available resources.

In arid regions, rotational grazing helps preserve soil quality and ensures pasture regeneration. In wetter areas, continuous grazing may be possible due to faster grass regrowth. Proper grazing techniques also minimize soil compaction and erosion, contributing to long-term land health.

Circular farming practices

Additionally, grazing systems often integrate with other agricultural practices. For instance, cattle can graze on crop residues post-harvest, reducing waste and enriching the soil with organic matter.

This integration supports circular farming approaches, which enhance sustainability and resource efficiency.

Despite its benefits, cattle grazing must be carefully managed to avoid overgrazing, which can deplete vegetation, increase soil erosion, and reduce water retention capacity.

Methane emissions in cattle

Livestock contribute 14.5% of global greenhouse gas emissions. Methane, primarily released by cattle through burping, constitutes the largest share.

Grazing cattle, that consume more fiber from grass, produce more methane compared to feedlot cattle or dairy cows. The United States alone is supports 9 million dairy cows and over 64 million beef cattle, making the mitigation of methane production crucial.

“Beef cattle spend only about three months in feedlots and most of their lives grazing on pasture,” explained Professor Kebreab.

“We need to make this seaweed additive or any feed additive more accessible to grazing cattle to ensure sustainable farming while meeting global meat demand.”

Challenges in reducing methane emissions

Lowering methane emissions in grazing cattle presents unique difficulties. Unlike feedlot or dairy cows, grazing cattle roam far from ranches for extended periods, which makes daily supplementation complicated.

However, ranchers often provide dietary supplements during winter or when grass availability declines. This study aimed to overcome these logistical barriers.

The researchers conducted a 10-week experiment on a Montana ranch, dividing 24 beef steers into two groups.

One group received the seaweed supplement in pellet form, while the other did not. Despite voluntary intake, emissions dropped by nearly 40% in the supplemented group.

Professor Kebreab noted that most previous research took place in controlled settings. Fewer than half of these methods are effective for grazing cattle. This study represents a significant step in addressing the challenges unique to pasture-based systems.

How seaweed reduces methane in cattle

Seaweed supplements reduce methane emissions by interfering with the gut microbes responsible for producing methane. The researchers suggest delivery mechanisms like lick blocks to make supplementation more practical for ranchers.

“This method paves the way to make a seaweed supplement easily available to grazing animals,” said Professor Kebreab.

Lick blocks could simplify the process, ensuring consistent access for cattle even in remote grazing areas.

Environmental and social benefits

Pastoral farming sustains millions of people globally, often in regions most vulnerable to climate change.

This study on reducing methane emissions in beef cattle offers a scalable solution to improve environmental sustainability while supporting livelihoods. By reducing emissions, cattle grazing could contribute positively to global efforts against climate change.

Professor Alison Van Eenennaam from UC Davis highlighted related efforts in the same PNAS issue. Her article emphasizes improving livestock efficiency in low- and middle-income countries through better genetics, feeding, and health practices.

“This approach is key to meeting global meat demand while limiting greenhouse gas emissions,” said Professor Eenennaam.

Seaweed supplements and methane mitigation

The research marks a significant advancement in sustainable cattle farming. It bridges the gap between practical challenges and environmental goals, ensuring methane mitigation without compromising cattle health or productivity.

Supported by Matador Ranch in Dillon, Montana, this work sets the stage for broader implementation of seaweed supplements worldwide.

Postdoctoral researchers Paulo de Méo Filho and John-Fredy Ramirez-Agudelo also contributed to the study. The findings highlight the importance of innovative, science-based approaches to combat climate change while supporting global food security.

Future research may refine supplementation methods further, making them accessible to a wider range of farming systems.

The study is published in the journal Proceedings of the National Academy of Sciences (PNAS).

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