In the 1960s, scientists discovered that halogenated compounds such as chloroform and bromochloromethane could inhibit methane-generating microorganisms, also known as methanogens. This was important because agricultural scientists were trying to make livestock farming more efficient. Ruminants (cows, sheep, goats, deer, giraffes) produce the gas methane when they digest plant matter. Scientists reckoned between 2 and 12 percent of all the energy from feed was being lost as gas. If they could reduce methane production, they could increase yields of meat, milk and other products.
In one experiment, feeding chloroform to sheep reduced their methane emissions by between 30 and 50 percent. The results were even more dramatic with bromochloromethane: a reduction of 70 percent. But there was just one problem. The halogenated compounds were toxic. They were harming the animals and leaving residues in the meat and milk. The research was abandoned.
Even tiny interventions in complex systems can have wildly unpredictable consequences
Now, methane reduction has taken on a new urgency. In the intervening decades, methane has been identified as one of the greenhouse gases responsible for causing dangerous climate change. The scientific community, governments, NGOs, charities, captains of industry, corporations, brain-dead celebrities and pop stars all agree that we must reduce emissions drastically to save the planet.
We’re told that about 5 percent of all greenhouse gas emissions come as a result of agriculture. Which isn’t actually all that much, when you think about how fundamental agriculture is to human life. Unfortunately for the ruminants of the West, efforts to focus on larger sources of emissions, such as China’s insatiable hunger for fossil fuels, are complicated by white people’s current role as the boogeymen of history.
And so livestock and their emissions – often referred to under the rubric of “cow farts” – have taken on an oversized importance in the global plan to tackle climate change. A new generation of methane-inhibiting compounds are now being used on livestock. Some are still being tested, while others, like DSM-Firmenich’s Bovaer, have already been approved for use. Bovaer is licensed for use in Brazil, Europe and, since last year, the US. The US Department of Agriculture has put aside $89 million to support the adoption of feed additives such as Bovaer. Things are progressing even faster in progressive Europe. In Norway, the government has mandated that by 2027, all cows must be fed methane-inhibitors by law.
Bovaer began life in 2008 as part of DSM’s “clean cow” initiative, in partnership with Penn State University. More than a million molecules were scanned until one was found that bound specifically to the enzyme responsible for methane generation in ruminants; broke down in a short period of time; and left no detectable residue in the animal’s meat or milk.
DSM patented the chemical compound 3-Nitrooxypropanol in 2010, and small-scale animal trials began over the next few years. Since then, 150 studies in 14 countries are reported to have proven, beyond a shadow of a doubt, that Bovaer reduces the amount of methane produced by cows and has no effects on their health or the quality and safety of the food they yield.
But still, there have been persistent, well-founded questions about the safety of methane-inhibitors, Bovaer in particular. The rumen – the largest of a ruminant’s four stomachs – is a marvel of natural engineering. A cow’s rumen has a capacity of up to about 200 liters, the same as your average bathtub, and contains billions upon billions of microorganisms, working in harmony to produce food for themselves, their host – and, eventually, us. As we all should know by now, even tiny interventions in complex systems can have wildly unpredictable consequences. This insight is the basis of chaos theory – remember Jeff Goldblum’s louche Dr. Ian Malcolm in Jurassic Park? – which famously posits that a butterfly flapping its wings can generate a tropical storm on the other side of the world. Disabling an entire species of microorganism in the rumen of a cow is not a tiny intervention, however. On a larger scale, it would be like, say, killing all the wolves in Yellowstone National Park. Look up what happened when the government actually did that.
Critics have already suggested a number of plausible mechanisms for how Bovaer might harm cows, including by changing the crucial balance of pH (acidity/alkalinity) in the rumen, which is regulated by methanogens, to altering the composition of the microbes themselves.
The studies don’t all say Bovaer is safe, either. Some have shown, for example, that cows on Bovaer eat and drink less and have smaller ovaries and hearts. Another study detected a metabolite of Bovaer in the milk of 75 percent of all cows tested. Rats fed higher concentrations of Bovaer developed fertility issues and cancers. The UK’s Food Standards Agency has raised concerns about these studies, but that didn’t stop Bovaer from being approved there.
More worrying evidence has emerged in recent months. In Denmark, where farmers began trialing Bovaer at the beginning of October, there have been reports of cows sickening, producing less milk and even having to be euthanized after collapsing. Multiple farmers have come forward to speak to news outlets such as Jyllands-Posten and videos have been circulating on social media, including one particularly grim video of a farmer carrying a stricken cow on a forklift truck. The farmers swear it’s the Bovaer. What else has changed? It has to be the feed.
The National Association of Danish Dairy Producers is now investigating and has asked the Danish government to declare a moratorium on the use of Bovaer until further safety-testing can be carried out. The association also wants its farmers to sign a declaration that if their cows get sick, they’ll stop using Bovaer. Animal welfare groups in Denmark, including the governing body for the nation’s vets, are also taking a close interest, as they should.
An alternative would be simply to return to grazing animals on pasture and to smaller-scale farming
To me, this looks like a very familiar story. It’s the story of food in the 20th century, of the massive changes that have taken place in the way food is produced and how we eat. Control of the food supply has been consolidated in the hands of corporations, and new ingredients, additives and adulterants have been introduced, with the approval of regulators, but without proper testing. These include high-fructose corn syrup, seed and vegetable oils, colored food dyes, preservatives, humectants and emulsifiers – and now Bovaer. It’s only decades later, as chronic disease reaches epidemic levels and threatens to bankrupt US healthcare, that the state of the food supply is finally being given the scrutiny it should always have had.
It’s also worth mentioning that the premise behind Bovaer is a fundamental mistake. It’s a misunderstanding of the way the cycle of carbon in the environment, into and out of living things, works. Grazing cows don’t simply pour ever-increasing quantities of methane into the environment that weren’t there before. Multiple studies have shown that well-managed grazing systems sequester enormous amounts of carbon in the grass and soil, offsetting any gases produced by the animals themselves. It’s only when you stick animals in industrial feedlots and start giving them wheat, corn and soy shipped over large distances that the balance of carbon is thrown out of whack. These concentrated animal-feeding operations are the hallmark of corporate-controlled agriculture. In short, Bovaer is a new product designed by corporations to reduce the harmful effects of corporate agriculture.
An alternative would be simply to return to grazing animals on pasture and to smaller-scale farming. This is often referred to as “regenerative agriculture,” but really it’s just agriculture as it was always done until the middle of the last century.
Robert F. Kennedy Jr., US Secretary of Health and Human Services, is a long-term champion of regenerative agriculture. He’s also an avowed enemy of processed food and corrupt food-safety regulations. Bovaer seems like a perfect case for him to focus on. Let the cows fart and burp, and corporations find another kind of hot air to monetize.
This article was originally published in The Spectator’s January 19, 2026 World edition.
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