State-of-the-art techniques to reduce climate-warming cow methane
Respiration stalls are an important step toward developing solutions for reducing methane emitted from cow
4 September 2024
6 minute read
By: New climate-controlled animal respiration stalls in the Cornell College of Agriculture and Life Sciences – the only ones currently operating in the US – will allow researchers to definitively measure, verify and monitor methane and other gas emissions from cows. This information will support a slate of investigations aimed at improving the sustainability and productivity of farms around the world.
The stalls or “chambers” are similar to large barn stalls that house cows, but are fully contained as a single unit with climate control to support the health and welfare of the animal.
Four Cornell University Animal Respiration Chambers supported by Cargill, Genesee Valley Regional Market Authority, and Balchem Corporation were unveiled at a ribbon-cutting event in April 2024 at the Large Animal Research and Teaching Unit where the chambers are housed.
Other funders for the $2 million animal respiration chambers include the New York State Department of Agriculture and Markets; Cornell CALS and the Department of Animal Science leadership; and the Cornell Atkinson Center for Sustainability.
The opening marks an important step toward developing solutions for reducing methane – a potent greenhouse gas – emitted from cows. Roughly 40% of all global anthropogenic methane emissions come from livestock agriculture, mostly from cow burps.
“The respiration chambers are considered to be the gold standard to monitor methane emissions from cows,” said Joseph McFadden, associate professor of dairy cattle biology in the Department of Animal Science (CALS). McFadden has spearheaded Cornell’s efforts to acquire the chambers and conduct livestock methane mitigation research.
“There are a lot of untested methane mitigation and monitoring technologies out there,” he said, “but the only way you can provide absolute quantification of gas emissions is by using a respiration chamber system.”
The animal respiration chambers are stainless steel with large doors and windows, designed to ensure the safety, nutrition and comfort of the animal while methane is being measured. They are large enough to hold a cow, or any other livestock animal. They are climate-controlled and they monitor oxygen consumption and methane, CO2 and hydrogen emissions in real time, taking measurements every 2 to 10 minutes. Researchers may put individual cows in a chamber in order to get an absolute measure of gases consumed and produced.
Measurements of gas exchange are key to understanding overall energy use – or energetics – in cows. For example, cows lose on average between 6% to 7% of the energy they consume to methane gas produced during digestion of carbohydrates. In order to get a balanced accounting of a cow’s energetics, researchers must estimate heat loss, which can’t be directly measured. They do that in large part by measuring the amount of energy from food that is used up by gases, digestion, urine and feces, metabolism, tissue and milk. They can apply this data to indirectly calculate heat loss.
By balancing the energy equation, researchers can then consider how effectively different diets and feed additives may optimize meat and milk production and animal health, and minimize greenhouse gas emissions and nutrient waste.
The chambers will also be used to improve Cornell’s nutritional modeling software, called the Cornell Net Carbohydrate and Protein System (CNCPS). The model is used to formulate diets for approximately 70% of lactating cows in North America, and has been adopted in more than 40 countries. The model allows a nutritionist or farmer to input feed ingredients to formulate a diet specific to the cows, feeds, and conditions, and the program will accurately predict milk yield.
Michael Van Amburgh, professor of animal science who has led development of CNCPS, initially applied foundational data to understand cow energetics acquired through animal respiration chambers at the U.S. Department of Agriculture’s Agricultural Research Center in Beltsville, Maryland, from the 1960s to the ’80s. Researchers now understand much more about cows’ amino acid and fatty acid requirements, Van Amburgh said. Also, today’s cows are bred with genetics to improve the efficiency of converting nutrients into milk and meat.
While these advancements may not affect milk volume per se, the cows do make more milk fat and protein depending on diet, which the old data doesn’t capture.
“These chambers can be invaluable because they will allow us to refine all of these energetics calculations that were done 60 and 70 years ago in cows that were very different than the modern cow and under conditions where we knew much less about specific nutrient requirements,” Van Amburgh said.
McFadden has been leading an effort to understand how feed additives may inhibit methane production in cows. He and colleagues are investigating whether seaweed or its active ingredient, bromoform, could safely limit emissions. In 2020, an Australian research group found that adding a native seaweed to a cow’s diet decreased methane emissions by 80%.
While promising, more work is needed to understand where that energy is redirected in the cow, which can then affect modeling of nutrient use, McFadden said. He is principal investigator of a $1.5 million grant from the California Department of Food and Agriculture to investigate interactions between dietary fatty acids, seaweed and bromoform on enteric and manure methane emissions and energetic conversion in lactating dairy cows.
Kristan Reed, assistant professor of animal science (CALS), also focuses on how diet and supplements impact methane and other greenhouse gas emissions. She integrates the results of dietary intervention within a whole farm context, which include downstream emissions from manure management and crop production.
“Being able to connect the manure composition to dietary interventions for enteric methane will allow us to better estimate emissions during manure storage,” she said. The chambers also have the capacity for adding sensors to detect ammonia released from manure.
Researchers would like to understand enteric methane emissions as they apply to an entire herd. Julio Giordano, associate professor of animal science (CALS), director of the Cornell Agricultural Systems Testbed and Demonstration Site (CAST) for the Farm of the Future, director of the Dairy Cattle Biology and Management Laboratory and an associate director of the Cornell Institute for Digital Agriculture (CIDA), has been developing and implementing data-driven technologies, precision tech and innovations that allow farmers to automate or semi-automate management tasks in order to create the farm of the future. A big piece of his research has been to advance wearable sensors on cows that directly measure biometrics.
“One of the uses of the chambers will be to validate measurements from sensors that are currently under development,” he said.
Giordano and colleagues are in early discussions with an industry partner to develop a ruminal bolus, a sensor implanted in the cow’s rumen, where methane is produced.
“That would be the ideal tool to have in the future, to monitor individual cows,” he said. “One of the limitations of estimating methane production at the farm level and the potential benefits of mitigation strategies is that we do not know how much methane is being produced by individual cows.”
Along with validating sensors under development, the animal respiration chambers can measure absolute emissions for a few individuals, and that data can be extrapolated to herd level.
Developing individual sensors will also be important for greenhouse gas accounting on farms as carbon credit markets emerge, where measuring enteric emissions of methane will be key.
