A prototype vaccine from ArkeaBio, a US start-up, cut methane emissions by 13 per cent in a first trial involving 10 cows, offering a potential way to reduce the huge climate impact of cattle farming.
A start-up has developed a vaccine that cuts methane emissions from cow burps, with plans for a commercial launch within three years.
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| Cows’ digestive systems produce large amounts of methane, a potent greenhouse gas Stephen Dwyer / Alamy |
Cattle produce methane as a byproduct of fermenting grasses and hay in their rumen, the first part of their digestive tract. Agriculture is the biggest source of human-caused methane pollution in the world, largely driven by the burps and farts from the billion cattle farmed globally.
US company ArkeaBio has spent the past 18 months developing a vaccine to target methane-producing bacteria that live in a cow’s digestive system.
Cows given the prototype vaccine produced 12.9 per cent less methane over a period of 105 days, according to results from a 2023 trial seen by New Scientist, with no adverse side effects or disruption to growth rates.
The trial was conducted in partnership with Texas A&M AgriLife Research, the agricultural agency of the state of Texas. It involved 10 cows, with five acting as a control group and the other five cows receiving a vaccination in the neck, followed by a booster shot 56 days later. The results were presented at the American Society of Animal Science annual meeting in Calgary, Canada, this month.
A second live trial with 14 cows began in June this year and is still ongoing. Early results suggest a methane reduction of at least 13 per cent per cow, with the effects expected to last beyond three months, says Cliff Lamb at AgriLife.
Scientists have been working for decades on the idea of a methane-busting vaccine for cows with little success, but dramatic cost reductions in biotechnology mean a vaccine is now a commercial possibility, says Colin South at ArkeaBio.
Methane emissions can already be reduced by changing a cow’s diet with feed additives that inhibit the activity of methanogens, the bacteria that produce the methane in a cow’s digestive system. But such additives are only useful for farmers who actively feed their cattle, rather than letting them graze on pasture. Some pasture-grazed cattle can spend months in rangelands without any human contact.
Richard Eckard at the University of Melbourne, Australia, says a methane vaccine “is probably the only option that is really going to make an impact” on emissions from grazing cattle. “If the livestock industry has to make a serious contribution to reducing its greenhouse gas emissions, a vaccine is an essential step forward,” he says.
ArkeaBio’s prototype vaccine works by stimulating the cow’s immune system to produce antibodies in its saliva, which would target methane-producing microbes in the rumen.
The company is aiming to bring a vaccine to market that reduces methane emissions by 15 to 20 per cent per cow, sustaining that reduction for at least 3 to 6 months. South says the trial results are promising but more improvements are needed before the vaccine can launch. “We’re comfortable with our mechanism of action,” he says. “The most important thing to do is show that the mechanism of action works, and then you can take the tools of biotechnology to just expand that performance.”
Lamb says ArkeaBio’s results are the “first evidence” a vaccination could have a meaningful impact on ruminant methane emissions. “The rumen of a cow is always changing because it’s made up of bacteria and other microbes, and so the population is always changing,” he says. “So it’s quite exciting to be able to see an actual decrease… and that we are seeing it in a second experiment is even more exciting.”
Initially, ArkeaBio plans to sell the methane reductions on the carbon credits market for $40 to $70 per tonne of carbon dioxide equivalent. South predicts a commercial vaccine will be ready in three years and rolled out to millions of cattle within five years.
Alexander Hristov at Pennsylvania State University says ArkeaBio’s results seem “promising”, adding that a 15 to 20 per cent reduction in methane emissions would be “substantial”. “This is a good approach but there is a long way to be sure that it works, [that] it delivers consistent results over divergent production systems, [that] there is no adaptation of the rumen methanogens, [that] it is economically feasible, and [that] it has no side effects,” he adds.