The controversial quest to make cowpods less harmful

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It’s an oppressively hot morning in the barn, even in the shade of the long open space where the cows feed. On a typical farm they would gather around a trough, but here at UC Davis they feed from special blue containers that recognize when and how much everyone is eating. It’s like Weight Watchers, only the researchers here aren’t so interested in the numbers of these cows as they are in how much they burp.

Animal scientist Frank Mitloehner leads me to a different type of automatic feeder that could easily be mistaken for a miniature wood chopper. He grabs a handful of alfalfa pellets, which the machine dispenses when it detects that a cow has stuck its head in. “It’s like candy for them,” says Mitloehner. I stick my head into the machine when Mitloehner points out a small metal tube inside: “This probe measures the methane that you exhale, and every three hours in all animals in this study.”

Cows have a serious emissions problem. In order to digest tough plant material, their cave-like stomachs act as fermentation tanks. They are teeming with methanogens, microbes that process cellulose into volatile fatty acids that the cows turn into meat and milk. But these methanogens also produce methane, a particularly unpleasant greenhouse gas that’s 80 times more powerful than carbon dioxide because its molecules vibrate to absorb infrared radiation. These gases trap heat, and that means more global warming.

“The methane is a by-product – an unintended consequence, I would say – of the unique ability of ruminants to digest cellulose,” says Mitloehner. But just because cows can eat doesn’t mean it is easy for them. Because the plants that cows eat are poor in nutrients, the animals have to eat plenty of food to survive and regularly pull it out of their four stomachs to ruminate on them – this is “rumination”. This leads to incessant burping, or as scientists call it, enteric emissions.

Now you multiply those burps by the huge cattle population in the world. To satisfy mankind’s boundless appetite for beef and milk, a Billions of head of cattle now roam the planet. A paper appeared in the magazine in September Natural food An international team of researchers found that the global food system is responsible for an incredible 35 percent of all greenhouse gas emissions. Beef is responsible for a quarter of these food emissions, and another 8 percent comes from milk production.

However, methane only lasts about a decade in the atmosphere, while carbon dioxide lasts for centuries. If scientists could figure out how to get cows to stop burping as much, it would greatly reduce emissions, and we would see the climate effects almost immediately. Mitloehner and other researchers are experimenting with food additives such as seaweed, Garlic and even essential oils from plants like coriander seeds, which change the intestinal environment of animals in different ways, for example by disrupting the enzymes that produce methane. They also play with biochar – basically charcoal – which soaks up methane in the intestines.

That is why Mitloehner goes to great lengths to quantify the nutrition of his cows: with high-tech troughs and methane detectors that dispense snacks, he can show how well a certain technology can reduce intestinal emissions. “We have found that, depending on the additive, we can reduce enteric emissions by between 10 and 50 percent, and that is sensational,” says Mitloehner.

Earlier this year has a team led by his colleague from UC Davis, animal scientist Ermias Kebreab. released research a gas reduction of up to 82 percent with algae additives. But studies by scientists testing other additives have shown less effectiveness. A study from 2019 von Wageningen University and Research, who looked at the organic compound 3-nitrooxypropano or 3-NOP, found a reduction of up to 50 percent. One of researchers in the UK and Switzerland found that agoline, a blend of essential oils, reduced methane production by only 6 percent. In New Zealand, cows fed tannins showed a decrease of 13 percent.

And the concept of introducing a feed additive for the world’s billions of cows faces some logistical challenges. “The truth is that the benefits of algae are likely to be far more limited, both in terms of their ability to reduce methane emissions from cows and their potential to scale to the extent of the problem.” wrote Researchers Matthew Hayek and Jan Dutkiewicz in WIRED earlier this year. They found that cows produce the most methane when they graze in a pasture and eat all that grass – the hard to digest stuff. Most cattle spend most of their lives here; they only live in the last few months, when fattened for slaughter, on pylons where it would be easy to add additives to their diet. The researchers estimated that cows only burped 11 percent of their lives methane at feeding grounds during those months.

That’s a problem, admits Mitloehner. “The challenge will be to get these in free-range cattle that are not fed from a trough,” he says. “One way could be through salt licks or perhaps through drinking water. Work is also underway to include these agents in a slow release bolus that will be introduced into the cow’s gastric system. “

He also wants to avoid side effects. “The higher you go with yours [emissions] reduce, the more likely it is to have unintended consequences, ”he says. For example, researchers need to track the animals’ weight to make sure the additive doesn’t interfere with growth. You also need to consider palatability – cows may not like it when their food tastes like garlic. Or the animal may belch less, but its milk may taste strange. “We have to find out what the happy middle is,” he says.


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