Cows Genetically Modified to Burp and Fart Less Could Cut Methane Emissions by Half

Cows that have been genetically modified so they burp and fart less could have a major impact on climate change—potentially helping to reduce global warming by cutting methane emissions by half, scientists have said.

Methane is a greenhouse gas that is far more potent than carbon dioxide. It is released when biological material breaks down, such as during a cow's digestive process. While the burning of fossil fuels is by far the biggest contributor to anthropogenic climate change, methane from the agriculture industry also has a role to play—and this mostly comes from cattle releasing the gas.

Previously, scientists have proposed different ways to reduce methane emissions from livestock, such as introducing dietary changes. However, this is unlikely to make a big difference in terms of climate change.

In a study published in Science Advances, a team of researchers has identified a group of genetically inherited gut microbes that regulate how much methane a cow produces. By finding these microbes, researchers could find a way to manipulate them so the cow produces far less methane.

"Most gases are emitted at the front end of the cow; at least 90 percent of the methane is burped," study author John Wallace told Newsweek. "If methane production is inhibited, there would usually be less gas emitted."

The team examined over 1,000 dairy cows from the U.K., Finland, Italy and Sweden. They looked at variations between genes before identifying a core microbiome that was present in half of the animals. A computer algorithm was then used to predict methane emissions based on the composition of the microbiome.

Researchers believe that based on their findings, cows could be selectively bred to produce fewer methane emissions—by finding the lowest methane producing cows and breeding them, while leaving out the high emitters. By getting rid of the biggest emitter, methane could be cut by 50 percent, Wallace told New Scientist.

"We know of no downside to lowering methane emissions in this way," Wallace said. "However, there is no upside either—except for the environment." In the study, the scientists also looked at whether reducing emissions would help to increase milk production—but it did not. "This is important, because improved feed efficiency would have been a great selling point to the farmer and breeder," Wallace continued. "Our alternative strategy would be to use our data to breed for improved feed-to-milk efficiency using the microbiome as selection trait. That would lower methane emissions too."

He said the next step will be to work out exactly what bovine genes are involved in the process and what they do.

File photo. The agriculture industry is a major source of methane. iStock