How cleaner cow burps could help fight climate change

First, let's get one thing straight. Despite what you may have heard, it is cow burps, not cow farts, that are the real climate change problem.

Here's how it works: Cows digest their food in four-part stomachs, including a "rumen," which is a site that allows for fermentation - a process that gives off a lot of carbon dioxide and methane gas, as microorganisms aid in the process of digestion. That gas has to get out of the cow's body somehow - hence, burps. "Approximately 132 to 264 gallons of ruminal gas produced by fermentation are belched each day," notes the Penn State College of Agricultural Sciences.

And because we have so many cows - where would human civilization be without them? - this really adds up. Indeed, according to the EPA, so-called "enteric fermentation" in cows and other ruminant animals, like sheep and goats, contributed 26 percent of the country's total emissions of methane, a hard-hitting greenhouse gas with much greater short-term warming consequences than carbon dioxide does (though the latter packs a far greater long-term punch).

Globally, meanwhile, methane emissions from livestock are an even bigger problem. Overall, the livestock supply chain emits 44 percent of the globe's human-caused methane, according to the U.N.'s Food and Agriculture Organization - and a large slice of that comes from cattle's methane burps. So anything you could do to cut down on cow belching would, literally, help save the planet.

The ideas for how to do this have been numerous - and sometimes hilarious. We've heard about cow backpacks, for instance, to capture methane and put it to use. And there are also more mundane solutions like simple "husbandry," says Johan Kuylenstierna, policy director of the Stockholm Environment Institute.

"You could reduce emission intensities - i.e. emissions per kg meat or milk, by about 30 percent if people in a given region adopted the good practices of the top 10 percent of farmers that have the lowest methane emissions," Kuylenstierna says by email, citing the FAO. This includes keeping animals healthier, giving them better diets, and managing their reproduction to lower their overall emissions.

But one fundamental way of fixing the problem involves trying to change the chemistry of what's happening in cows' rumens - after all, methane emissions represent lost food energy that could have gone towards cow growth or milk production. For some time now, the Dutch life sciences and materials company DSM has been pursuing such a solution, which it appropriately calls its "Clean Cow" project.

DSM is a Netherlands-based life and materials sciences giant with about $11 billion in annual sales - including 32 percent of its market in animal feed. The company has created a powder that can be added to cow feed that, it says, can produce "a reduction of over 30 percent in methane emissions with no negative impact on animal welfare, performance, or the amount of feed they consume." And now, newly published science backs this idea up.

DSM worked with a top dairy sciences researcher who focuses on methane emissions, Alexander Hristov of Penn State University, to study the clean cow technology - what they more technically called a "methane inhibitor." And they got promising results.

Hristov and colleagues, including several researchers from DSM, designed and carried out a trial in which 48 cows, receiving varying amounts of the inhibitor in their feed, were observed over 12 weeks. Their methane emissions were measured when they put their heads into feeding chambers which also had atmospheric measurement sensors, and also through nostril tubes attached to canisters on the backs of the cows.

The result was that the inhibitor "decreased methane emissions from high-producing dairy cows by 30 percent," the research found.

"The present experiment is, to our knowledge, the first to document this effect using a methane inhibitor with potential for widespread use in the livestock industries," notes the study. It was just published in an influential scientific journal, the Proceedings of the National Academy of Sciences.

The substance "blocks one of the steps of the enzymatic process that produces methane from carbon dioxide and hydrogen," explains Hristov. And he notes that in that process, energy is actually being lost in the form of methane. So with less methane generated, Hristov says, the cow has more energy that can instead be converted to growth and milk production.

"In our case, that energy didn't go to milk production, but the cows actually gained more body weight, basically the energy was directed towards body weight gain," says Hristov. The published study discloses that the research was partially supported by DSM.

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To get a further read on the research, I contacted several researchers who were not involved in the study. Ermias Kebreab, a professor in the department of animal science at the University of California, Davis, commented by email that "I think it has a real potential to reduce enteric methane emissions. However, before it can be recommended for wide use, the mode of action should be explained well and the long-term impact on the animal should be studied."

Kebreab said that he wanted to know how long the methane inhibitor lasts "in manure or soil after excretion," and added that "research on the toxicity of the compound and residue should also be conducted."

"It would be important to extend the study to beyond the 12 weeks of the study, say over a full season or even through multiple seasons to fully assess impact on animals first of all as well as on products quantity and quality," added Francesco Tubiello, an expert with the U.N.'s Food and Agriculture Organization, by email.

Shown an earlier version of the research, Jeffrey Firkins, an agricultural researcher at the Ohio State University, noted that the design is powerful because it captures a "dose-response" relationship - the more of the inhibitor cows were given, the more their methane emissions appeared to go down. "Anything like this should be repeated of course, but for one experiment, it looks pretty robust," Firkins said.

The real trick, though, may be getting farmers to adopt the technology - but according to Hugh Welsh, president of DSM North America, they may ultimately have an economic incentive for doing so.

"We're looking to a day when there really will be a price on carbon, or where a farmer will be able to sell carbon credits for using this in his feed," says Welsh. He says the company hopes to be able to take the inhibitor commercial by 2018.

So in sum, cows remain a major contributor to climate change, and just as with caps on tailpipe and smokestack emissions, we will need to find a way to curb that contribution. There are many contending solutions - but perhaps a key of the fix will turn on changing what's happening in a cow's stomach.