
Photo: Melanie Stetson Freeman/CSM.
A heifer stands inside a methane chamber at Cornell University, June 7, 2024, in Ithaca, New York. Researchers are studying how to reduce methane emissions from dairy cows.
When he was only 11, one of my grandsons gave up eating beef after learning in school about the effects of cows’ methane emissions on global warming.
I guess it’s fortunate that there are people researching ways to make cows “less gassy.” But some of the research sounds like it’s not much fun for the cow.
Stephanie Hanes of the Christian Science Monitor reported recently on work at Cornell.
“On the campus of Cornell University, within an intricately monitored and carefully sealed chamber, there is a cow. Scientists carefully record what this cow eats and what she drinks. They open the chamber only once a day, so as to limit disturbances to her environment. Every breath she takes – or more crucially, exhales – is also measured to its molecular level. There is hydrogen. There is carbon, recorded down to its isotopic composition. There is oxygen. And, most important to this state-of-the-art study, there is methane.
“Methane is a naturally occurring gas that comes from a variety of biological and industrial sources, from oil- and gas-well leaks to decomposing garbage to, well, cow burps. It is also one of the world’s most potent greenhouse gases – far more heat-trapping than carbon dioxide. …
“ ‘There is growing awareness amongst environmental advocates, policymakers, that reducing methane emissions is the fastest way to reduce warming,’ says Dan Blaustein-Rejto, director of food and agriculture at the nonprofit Breakthrough Institute. …
“Although exact percentages are difficult to determine, researchers estimate that cows are responsible for around 30% of U.S. methane emissions. This is largely because cattle, like goats or sheep, are ruminants: animals with four-chambered stomachs that ferment grass and other vegetation into consumable food. And a natural by-product of rumination is methane. …
“According to the U.S. Department of Agriculture, there are 28.2 million beef cattle in the U.S., along with 9.36 million dairy cows and 33.6 million calves. And those numbers pale in comparison to countries such as India, which has an estimated 61 million milk cows, or Brazil, with around 234 million beef cattle.
“With growing pressures from policymakers and climate advocates, then, agribusiness and scientists are trying to figure out how to make individual dairy cows more productive, which could lead to smaller herds, while at the same time trying to find ways to make cow burps — the body function that produces the most methane — less gassy.
“The first step to doing that, says Cornell associate professor Joseph McFadden, is to get good measurements of bovine methane in the first place. …
“ ‘The challenge comes in capturing the methane,’ says Joe Rudek, lead senior scientist at the Environmental Defense Fund. ‘Cows are breathing out this methane. You’ve got them walking around in a pasture, how do you capture that methane that’s coming out of the cows’ mouth and nostrils?’
“So instead of individually measuring each cow, scientists are trying to build up a robust sample size of measurements that would let them statistically predict methane emissions, both broadly and specifically. One contraption they use now is called the GreenFeed – basically a high-tech box with cow treats. When the cow puts her head into it to eat, the box measures methane and other gases. These instruments are portable, so theoretically farmers can use them in different locations.
“But, Dr. McFadden says, those measurements are not always exact. That’s why his respiration chambers are important. Because the pods are highly accurate, closed systems, they can calibrate other machines. … The chambers can help him monitor other inputs and outputs that can give clues about animal health and well-being, and about how the animal uses energy – as well as about other greenhouse gases, such as nitrous oxide. …
“Across the country, at the University of California, Davis, professor Ermias Kebreab is also working with dairy cows, and has his eye on some solutions. In addition to feed additives, he is measuring what happens when cows eat local agricultural by-products, such as the grape residue from winemaking. GreenFeed measurements are finding some promising initial results, he says.
“ ‘We found a 10% to 12% reduction in emissions,’ he says. ‘Animals were happy to eat it … and it avoids the emissions from putting it into a landfill.’ Not only that, he says, but grape pomace — the fruit’s leftover skin, seeds, or stems — seems to improve milk quality.
“ ‘It’s a win-win kind of situation,’ he says.”
More at the Monitor, here.






