Tuesday, July 03, 2018

These cows are on weed - To Reduce Gas Emissions From Cows, Scientists Look To The Ocean

Scientists think they can reduce greenhouse gas emissions by tweaking the food that cows eat. A recent experiment from the University of California, Davis suggests that adding seaweed to cattle feed can dramatically decrease their emissions of the potent gas methane. There's a pen at the University of California, Davis, where scientists were closely observing 12 research cows on a recent morning. Each animal is known by a four digit number — except for the friendliest one. "We just call her Ginger, she's the only one with a name," laughs graduate student Breanna Roque. On this morning, Roque is mixing up breakfast for the research cows. She's pulling out dark, gooey clumps of a seaweed species called Asparagopsis armata. Roque adds a little bit of molasses, too, which the cows seem to appreciate. She mixes it all thoroughly because some cows don't like the salty seaweed taste. As animal science professor Ermias Kebreab, who is leading the experiment, puts it: "It only works if they consume it." Kebreab says that as cows digest their fibrous food, methane is produced by microbes in the rumen, the first chamber of the cow's four-part stomach, in what he calls a "natural process of fermentation." It's kind of like how yeast produces carbon dioxide in beer. The cows then burp that methane out, into the atmosphere. He says belches are a bigger problem than farts: "Over 95 percent, actually, is from the mouth, from the front end of the cow." Kebreab says they're hoping that the seaweed can inhibit an enzyme that's involved in producing methane in a cow's gut, a chemical reaction discovered by researchers in Australia. To test the theory, the researchers divided the cows into three groups. One of the groups received a "high dose" of seaweed, amounting to 1 percent of its feed. Another received half that, and the final group received no treatment. The cows lumber up, each heading to its own specially prepared meal. They've been taught to come to the same stall every time to feed, unlocking it with a yellow sensor dangling around their necks. Roque says: "When it has to do with feed, they can be trained." To test whether the seaweed is working, the cows use a kind of breathalyzer at least three times a day, where they eat a cookie as they stick their heads into a machine that measures the gases in their breath. This is the third time they've run the experiment, each for a period of two weeks. Kebreab says they noticed a difference in emissions right away. "The results are almost immediate. You give [it to] them this day, and the next day you see the reduction." And the drop in methane was even more than they expected. He remembers the first numbers coming in. "When Breanna was sending me these results, I was like, are you sure?" Kebreab says. Their experiment found that the high dose of seaweed reduced methane production by more than half, what he describes as a "dramatic reduction in methane emissions."...MORE

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