LAUSANNE — Fighting climate change means limiting our greenhouse gas emissions, which for most of us means carbon dioxide (CO2). But methane is also a major problem. Though less persistent in the atmosphere, this gas has a warming power 25 times higher than CO2 . And the bulk of it is emitted by bloated bovines: cattle .

The UN's Food and Agriculture Organization (FAO) estimates that methane gas from the burps and flatulence associated with ruminant digestion accounts for nearly 40% of greenhouse gas emissions in agriculture, making it the leading source of emissions in this sector. To reduce these emissions, various possibilities are being explored, including adjustments to livestock feeding.

The Swiss company Zaluvida is developing the Mootral, a natural supplement made with garlic and orange peel that it intends to market later this year. This product promises to limit methane emissions by 30% by modifying the bacteriological composition of rumen. A European study led by the French company Valorex focused on the addition of cooked linseed to the daily diet of cattle. The announced result is a reduction in emissions of up to 37%. And a Swiss company called DSM Nutritional Products is banking on a synthetic food compound that would inhibit the enzyme responsible for the production of methane in the stomach. The product also boasts a 30% reduction in emissions and is expected to be released next year.

The real effect would rather be closer to 10% or 13%.

Keep in mind that these figures come from lab tests. In barns and pastures, the effects of Mootral and its ilk may not be quite so marvelous. "The real effect would rather be closer to 10% or 13%," says Andreas Münger, a researcher in agronomics.

Other feeding techniques have also been shown to reduce emissions. "It's the digestion of fibers from fodder and grass that causes the most methane emissions. Cereals can be added to the ration to limit fiber intake," Münger explains. And by adding cereals to the ration, the milk yield of the animal is increased at the same time. "It is also possible to genetically select cattle to emit less methane," he adds.

There's also, of course, the option of reducing the overall number of cattle . Fewer animals means fewer burps and back-side blasts. But that would mean changing our beef and dairy-product habits — a prospect that's at least worth chewing on.