Solution for climate-damaging burps and farts from cows

Researchers at the University of California, Davis and the Innovative Genomics Institute are conducting a multi-year experiment to alter the digestive processes in the stomachs of cows.

Cows, which are widely consumed around the world, produce significant amounts of methane, a powerful greenhouse gas that contributes to 30% of global warming.

The team uses CRISPR technology to genetically modify microbes in the cows' stomachs with the goal of reducing or eliminating these methane emissions.

“This is completely unprecedented,” said Ermias Kebreab, a professor of animal science at UC Davis. “Nobody has done this before.”

Possible solutions using pasta ingredients?

On average, a cow emits about 100 kilograms of methane per year, which is about half the emissions of a normal car. According to the Food and Agriculture Organization of the United States, cows are responsible for about 4 percent of global warming.

If the researchers' efforts are successful, they could potentially eliminate the largest source of man-made methane and significantly impact global warming trends.

While adding substances such as seaweed, oregano or garlic to cow feed can reduce methane emissions by up to 80%, this approach is only practical for about 10% of livestock in the U.S.—mainly dairy cows that are fed daily.

The same situation applies worldwide. The remaining livestock, mainly cattle, graze on pastures and survive on grass and forage. Implementing such dietary changes for these billions of free-roaming cattle would be logistically challenging.

Probiotic pills to the rescue

Methane emissions from cow burps come from gas-producing microbes in the cow's digestive system. By genetically engineering these microbes to produce less methane, researchers hope to reduce emissions before they are excreted.

“We are trying to find a solution to reduce methane that is easily accessible and inexpensive, with no restrictions or limitations, and that can be made available not just in California but worldwide,” said Matthias Hess, professor of animal sciences at UC Davis.

The scientists plan to develop a type of probiotic pill that could be given to cows at birth, potentially permanently altering their microbiome. This approach builds on previous successes in genome editing, such as breeding cattle without horns or with heat-resistant, smooth coats.

In contrast to these efforts, this project targets the microbiome itself and offers a potential solution that could be applied to different cow breeds.

Challenges and the way forward

A probiotic pill designed to reduce methane emissions from cows could also boost farm productivity. Cows lose up to 12% of their energy through methane burps, and other ruminants such as sheep and goats suffer similar losses.

Initial trials of this probiotic are being conducted at UC Davis, where researchers are monitoring methane emissions by tracking cows' burps to assess the effectiveness of the treatment.

However, challenges still lie ahead. While scientists have demonstrated the ability to edit the genome of microbes, so far they have only managed to alter a small portion of the microbes in the cow's gut. Researchers are still developing microbial genome editing tools and mapping the microbiome species, effectively evolving their methods as they progress.

Despite these concerns, the potential benefits of microbial editing are compelling. Methane is produced not only by cows, but also by goats, sheep, and even natural sources such as arctic permafrost and temperate wetlands. The insights gained from this research could lead to interventions in other animals and ecosystems, the researchers say.