A climate-friendly barista milk from cows that emit less methane has launched in selected UK coffee shops. The milk comes from livestock fed Mootral Ruminant, a cattle feed supplement by the Swiss-British agritech company Mootral. The food additive, developed by a team of veterinary researchers from Belgium, Denmark, Finland, Germany, Ireland, Japan, the Netherlands, the United Kingdom and the United States, cuts enteric methane emissions by up to 38%. It builds on the fact that microbial communities in ruminants’ digestive systems ferment crude plant fiber to short-chain fatty acids, which the cow takes up through its gut. This fermentation, however, also produces methane, a major contributor of greenhouse gases. When added to feed, Mootral changes cows’ gut methanogen content and microbial metabolic pathways to reduce methane in their burps. The supplement is a mix of garlic—known for the organosulfur compound allicin, which has antimicrobial properties—and flavonoids extracted from bitter oranges. In lab experiments, a team at the University of Veterinary Medicine in Hanover, Germany, found Mootral altered the composition of the microbial community of Archaea, the main producers of methane during rumen fermentation. In a farm study conducted in the Netherlands, Mootral boosted the cows’ milk yield by 4% and increased fat content too, with no changes to the milk’s taste and appearance. In Scotland, a commercial dairy farm with 400 dairy cows found that Mootral reduced methane emissions by 30% on average as measured with a hand-held methane laser detector. Another trial, conducted at the University of California Davis, measured a 23% drop in methane production. Thomas Hafner, CEO and cofounder of Mootral, says in a press release: “It’s time for us to help cows become part of the solution in the global fight against climate change.” Mootral next plans to focus on climate-friendly beef.