Researchers search for ways to limit belching bovines

November 09, 2016

Around the world, livestock emit about 14.5% of all greenhouse gas emissions each year — most of that coming from belching and farting cows. So in an effort to slow down the effects of climate change tied to these greenhouse gases like methane, scientists have been manipulating the things cows eat in an effort to get cattle to stop eructing so much.

As explained by an agricultural emissions researcher, Frank Mitloehner, although methane doesn’t linger in the atmosphere as long as carbon dioxide does—only about 20 years— it has a much larger short-term climate impact.

To understand this, you first need to know that cow’s stomachs are four-chambered systems. The methane producing part—called the rumen—is a massive cavity capable of holding a bathtub’s worth of saliva and cud. This chewed-up muck is called roughage. Humans get a lot of their fiber from indigestible plant-based foods. Cows can digest these plants too, thanks to gut microbes called methanogens that turn plant matter into fiber (which leaves the body as poop) and methane (which leaves the body as burp or flatulent).

If we get rid of—or go around—the methanogens, the methane goes as well, the article explains, so the central question for researchers is now how to shift rumen’s microbial ecology without losing the benefits those little buggers provide (namely, producing the fatty acids that give beef its robust flavor).

In Australia, for example, scientists are using seaweed, or more specifically, bromoform, a compound found in kelp that blocks methane byproduct but still allows the bovines to burp. A team of researchers fed seaweed to synthesized cow stomachs, then attached gas production monitors to see whether the algae diminished or escalated methane emissions. “At low levels, red seaweed—less than 2% of feed intake—can dramatically reduce methane emissions, cutting it back by 10 to 20%,” Rob Kinley, one researcher said.

Furthermore, based on cow’s love for grass, scientists at Aarhus University in Denmark are engineering “super grass” they hope can cut methane without starving the cows of other vital nutrients. Through genetic selection, they’re looking for DNA in fodder that could be engineered to yield less gas build up in the rumen.

Or, if not grass, how about meddling directly with the gut itself? The article explains that last year, a crew of Penn State researchers began adding 3-nitrooxypropanol, or 3NOP, into cow feed. Cows still get to burp, but the 3NOP binds enzymes to the bovine’s gut and prevents the gut microbes from producing methane. In experiments, cows with altered guts emitted 30% less gas than usual.

The problem with these fixes, however, is that most of them only work for a short while before the cow’s gut microbiology swings back to its usual, methane producing ways. This can take anywhere from a day to a few weeks or months, depending on the cow and the method, Mitloehner said.

So far, the best solutions for limiting the amount of gas that is produced also means feeding cows foods like corn that do not have a lot of fiber. This starves the methanogens of their precious roughage but makes for sicker cows that don’t live as long as their grass-fed counterparts.

“Our animals have become very efficient, just like our cars have become more efficient,” Mitloehner said in the article. So until the bioengineering solutions work out, it’ll be a while before you’re able to order a quarter pounder—hold the planet-warming cow burps.

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Category: Agriculture