Seaweed Feed Reduces Methane Emissions in Grazing Cattle by 40%

Feeding seaweed to grazing cattle can reduce their methane emissions by nearly 40%, providing an innovative and eco-friendly approach to lowering greenhouse gases. This breakthrough highlights the potential of sustainable farming practices to combat climate change while maintaining productivity in the agricultural sector.

Scientists have discovered that making a seaweed-based feed additive more accessible to grazing cattle can cut methane emissions by 40%, potentially advancing sustainability in cattle farming.

Seaweed is gaining attention as a sustainable farming solution. A recent University of California, Davis study showed that feeding grazing beef cattle a seaweed supplement in pellet form reduced methane emissions by nearly 40%, with no adverse effects on cattle health or weight. The findings, published in the Proceedings of the National Academy of Sciences on December 2, mark a significant breakthrough.

This study is the first to evaluate the impact of seaweed on grazing beef cattle globally. Previous research demonstrated that seaweed reduced methane emissions by 82% in feedlot cattle and over 50% in dairy cows.

How Much Methane Do Cattle Produce?

Livestock contribute to 14.5% of global greenhouse gas emissions, with methane from cattle burps as the largest source. Grazing cattle emit more methane than feedlot or dairy cows because their fiber-rich grass diet promotes higher methane production. In the U.S. alone, there are approximately 9 million dairy cows and over 64 million beef cattle.

"Beef cattle spend most of their lives grazing on pastures, where they generate significant methane emissions," explained Ermias Kebreab, senior study author and professor in the Department of Animal Science. He emphasized the importance of making seaweed or other feed additives widely accessible to grazing cattle to improve sustainability while meeting global meat demands.

Challenges in Reducing Grazing Cattle Emissions

Feeding grazing cattle daily poses challenges, as they often roam far from ranches for extended periods. However, during winter or grass shortages, ranchers typically provide dietary supplements.

In this study, researchers divided 24 beef steers, consisting of Angus and Wagyu breeds, into two groups: one receiving the seaweed supplement and the other not. The 10-week experiment, conducted on a ranch in Dillon, Montana, revealed that even voluntary consumption of the seaweed supplement by grazing cattle resulted in a nearly 40% reduction in emissions.

While most methane-reduction studies on feed additives occur in controlled environments with daily supplementation, such methods are less effective for grazing cattle. "This approach offers a practical way to make a seaweed supplement available to grazing cattle," said Kebreab. He suggested that ranchers could introduce the supplement through lick blocks, further enhancing accessibility.

Addressing Sustainability and Climate Change

Pastoral farming, which involves large grazing systems, supports millions globally, particularly in areas vulnerable to climate change. This study highlights how grazing systems can be made more environmentally friendly, contributing to efforts to combat climate change.

A related article in the same issue of PNAS underscored the need to enhance livestock production efficiency in low- and middle-income countries through improved genetics, feeding practices, and health measures. According to UC Davis Professor Alison Van Eenennaam, this is a promising strategy to meet growing meat demand while reducing greenhouse gas emissions.

The seaweed study involved contributions from UC Davis postdoctoral researchers Paulo de Méo Filho and John-Fredy Ramirez-Agudelo and was supported by Matador Ranch in Dillon, Montana.

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Source: sciencedaily‍