Scientists have discovered that making a seaweed supplement more widely available to grazing cattle can significantly lower methane emissions by 40%, potentially leading to more sustainable cattle farming practices.
Seaweed is proving to be a valuable resource in enhancing sustainability in cattle farming. A recent study from researchers at the University of California, Davis, revealed that providing grazing beef cattle with a pellet-form seaweed supplement resulted in a nearly 40% reduction in methane emissions, all without impacting their health or weight. This research was published on December 2 in the Proceedings of the National Academy of Sciences.
This study marks the first time seaweed has been tested on grazing beef cattle worldwide. It builds on previous findings that indicated seaweed could lower methane emissions by 82% in feedlot cattle and over 50% in dairy cows.
What’s the methane output from cattle?
Livestock contribute to 14.5% of global greenhouse gas emissions, with the majority stem from methane emitted when cattle burp. Grazing cattle are known to produce more methane than those in feedlots or dairy cows, largely due to a fiber-rich diet from grass. In the United States, there are 9 million dairy cows and more than 64 million beef cattle.
“Beef cattle typically only spend around three months in feedlots, while the majority of their lives are spent grazing and producing methane,” noted senior author Ermias Kebreab, a professor in the Department of Animal Science. “It’s crucial to make this seaweed supplement, or any feed additive, more available to grazing cattle to ensure that cattle farming is sustainable amid rising global meat demand.”
Challenges in reducing emissions from grazing cattle
Kebreab pointed out that providing daily feed to pasture-based cattle is more challenging than for feedlot or dairy cows, as they often graze at distant locations for extended periods. However, ranchers frequently supplement their diets during winter or when grass is limited.
In this study, researchers observed 24 beef steers, which included both Angus and Wagyu breeds, and divided them into two groups: one group received the seaweed supplement, while the other did not. The 10-week experiment took place at a ranch in Dillon, Montana, where the grazing cattle consumed the supplement voluntarily, achieving a nearly 40% reduction in methane emissions.
Most previous research to lower methane emissions via feed additives has been conducted in controlled settings with daily feedings. However, Kebreab emphasized that less than half of those methods effectively work for grazing cattle.
“This approach unlocks the potential to provide a seaweed supplement easily to grazing animals,” said Kebreab. “Ranchers might even offer the seaweed through a lick block for their cattle.”
Kebreab stressed that pastoral farming, which encompasses extensive grazing systems, supports millions globally, especially in areas susceptible to climate change. This research offers a pathway to enhance the environmental sustainability of cattle grazing, contributing to the fight against climate change.
In the same issue of PNAS, a related article underscores the need for improved efficiency in livestock production in low- and middle-income countries through advancements in genetics, feed, and health practices. UC Davis Professor and Cooperative Extension Specialist Alison Van Eenennaam, who authored the article, stated that this is a promising strategy to satisfy global meat demand while curbing greenhouse gas emissions.
Other contributors to the seaweed study include UC Davis postdoctoral researchers Paulo de Méo Filho and John-Fredy Ramirez-Agudelo.
This research received support from Matador Ranch in Dillon, Montana.
