Gassy cows rival oil industry's climate impacts

Here’s the thing about cows: They burp like teenage boys who’ve been chugging Mountain Dew.

The only difference is, bovine burps are a big problem for climate change. The burps — combined with less-frequent bursts of flatulation — are a side-effect of cattle digestion, and they're responsible for more than 20 percent of the nation’s heat-trapping methane emissions.

That’s two-thirds as much methane as the U.S. oil and gas industry produces.

California recently became the first state to take aim at gassy cattle, asking livestock and dairy producers to trim their methane emissions 40 percent by 2030. The strategy is raising eyebrows in Colorado, where there’s one cow for every two people. In Weld County, cattle outnumber people 2:1.

A lot of options are on the table: Everything from changing cattle breeding and manure management to strapping bovines with backpacks that turn their outbursts into energy.

Or cattle producers could make use of all that methane another way, by shoveling manure into high-tech anaerobic digesters that turn the waste into electricity.

The most obvious solution isn’t quite as grabby as electro-manure or backpacks — it’s simply a matter of improving cattle diets, said Shawn Archibeque, a Colorado State University assistant professor of livestock nutrition.

Grass and hay, the go-to dishes for cattle, increase methane emissions because the microbes that break them down produce more methane than the microbes that break down, say, alfalfa or wheat.

Easy fix, right? Wrong.

High-grain diets are more expensive than hay and grass meals, and they require more land, water and energy to produce.

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Cattle diets are a hot research topic, Archibeque said, so it’s not impossible to find the right balance. A lot of Colorado livestock producers are trying, Colorado Livestock Association CEO Bill Hammerich said.

After all, methane emissions are essentially wasted energy from food, so reducing methane means more bang for a producer’s buck.

“At the end of the day, if we look at a ruminant animal, somewhere between 3 and 12 percent of the energy they consume is going to be lost as methane,” Archibeque said. “Period. No matter what. That’s just how nature designed them. But we can do things to shift them from the 12-percent range over to the 3-percent range.”

The other major source of cattle methane emissions is manure, which makes up 8 percent of methane emissions. Manure is mostly made of undigested food, and just because the cow has passed the food doesn’t mean the digestive microbes are done working on it.

As the microbes do their thing in the light of day, they produce more methane, especially when the manure is stored in liquid lagoons rather than applied to fields or separated into liquids and solids.

If producers filter liquids out of manure, they can put it in digesters to produce biogas, which can be used to generate electricity. Colorado has one such digester, the Heartland Biodigester in LaSalle, but that operation has an exclusive contract with an area composting facility.

California is clearly intrigued by the digester concept — its methane ruling orders gas companies to work with the dairy industry to create five digester pilot projects by 2018.

Digesters also have drawbacks. They’re expensive — think millions of dollars — and it can be hard to find takers for the gas they generate because of the difficulties incorporating digesters into electric grids.

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Hammerich said Colorado producers are paying attention to the California regulations, although he doesn’t think they’d fly here.

“There’s just a general mood in the country today that is resistant to regulation," he said. “But this topic is on everyone’s minds. Call it climate change, climate variability, whatever you want, it’s a real issue and it’s something I think agriculture is going to deal with.”

OK, so what about those cow backpacks?

They've been getting attention since 2013, when Argentina's National Institute of Agricultural Technology tried strapping them on cows. The contraptions collected methane from cows' stomachs through tubes and stored it in pouches on their backs. Researchers proved they could use the stored gas to light homes, power refrigerators and even drive cars.

The backpacks were probably never meant for worldwide implementation — researchers said they wanted to prove collecting methane via backpack was possible and provide a solution for remote areas without access to power lines.

Archibeque, for one, isn't a member of Team Cow Backpack.

“I don’t think that’s going to be feasible,” he said. “We’ve got between 90 (million) and 95 million cattle in the U.S.

“That’s a lot of backpacks.”

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About the California law

One of many laws adopted this year targeting climate change, the law requires the State Air Resources Board to adopt regulations to reduce methane emissions from livestock and dairy manure management operations by as much as 40 percent below 2013 levels by 2030. Other parts of the law address emissions from landfills.

The board has to hold public meetings, consider feedback from stakeholders, conduct related research and provide incentives and infrastructure for some of the approved methods. All regulations have to be cost-effective and technologically feasible, and the board has the option to lower the 40 percent goal in 2020 if it doesn't seem feasible.