Cattle contribute to climate change. How can that be solved?

To understand methane emissions from cattle, start with a cow’s superpower: its rumen.

The rumen is the largest compartment of a cow’s four-chambered stomach, and it is the main player in turning even low-quality forage into high-quality animal protein. This occurs with the help of microbes that bustle in their 105-degree fermentation vat to break down plant fibers and other material, producing energy and nutrients for the animal.

Those microbes – more than a quadrillion in each rumen – generate gases as a byproduct of digestion; these are chiefly methane and carbon dioxide. Cattle release enteric gases, or those produced in the digestive system, each time they belch. And while methane and carbon dioxide are both notable as greenhouse gases, methane is the gas of interest in livestock production because it is so potent, far more capable of trapping heat that contributes to climate change.

Given these enteric methane emissions, some consumers have looked askance at cattle production and have disavowed beef consumption. Yet, with backing from the cattle industry, Colorado State University researchers are leading a nationwide quest to better quantify and reduce methane emissions from cattle.

“If we can reduce greenhouse gas emissions, that will connect people differently to agriculture and their food,” said Kim Stackhouse-Lawson, director AgNext, a CSU research group that advances the science of sustainable animal agriculture.

Stackhouse-Lawson, a nationwide leader in enteric methane research, was motivated to join the field as a student at the University of California, Davis when one of the first Meatless Monday activist events occurred in the college town. Having grown up in Northern California with sheep and cattle, she was perplexed; she had always seen agriculture and the environment as symbiotic.

“Cattle are eating forage that few other animals can eat, very often on ground that cannot be farmed, and they’re turning it into meat, leather and other products we can use. But they’re also contributing to climate change,” she said. “The question for us is, ‘How low can we get methane emissions and still have a productive animal that turns things we can’t use and eat into things we can use and eat?’”

The conundrum is increasingly urgent, as the cattle industry – like industries of all varieties – examines ways to curtail climate change to comply with environmental regulations, appeal to consumers, improve profit margins and attain benefits from emerging carbon markets.

“Studying greenhouse gases in the livestock industry is really about animal efficiency. The big win would be an animal with less environmental impact but higher feed efficiency, meaning its ability to efficiently convert feed to meat,” Stackhouse-Lawson said. “I’m excited by practical solutions that will make animals healthier, producers more profitable – and help the environment. We want to know, ‘Where’s that sweet spot?’”

One cow produces roughly 200 pounds of methane each year. It adds up: Livestock, chiefly cattle, produce 25% of U.S. methane emissions from human activities annually, according to 2022 data from the U.S. Environmental Protection Agency. Manure management is another key contributor.

To put that in context, methane accounted for 12% of all U.S. greenhouse gas emissions from human activities in 2022, according to the EPA. Carbon dioxide is the heavyweight in greenhouse gas emissions from human activities – accounting for about 80% of the total – and most of that is generated by transportation, industry and the production of electricity.

“It’s small in the scheme of things,” Stackhouse-Lawson said of methane emissions from cattle. “But that doesn’t mean we shouldn’t improve it.”

Enteric methane is of particular interest in Colorado, where beef cattle are the driver of an agricultural industry that annually contributes an estimated $47 billion in economic activity to the state, according to the Colorado Department of Agriculture.

Study of enteric methane – with the goals of successfully measuring and mitigating emissions – is a core research focus for AgNext. For instance, the center is now investigating how dietary fat, in the form of soybean oil, can be added to corn-based rations to reduce methane emissions as cattle are managed in feedlots during the final stage of beef production.

Studies of feed additives have been conducted before, but this one is notable for monitoring methane emissions at scale – examining outcomes in a large group of cattle, as would be found in a working feedlot.

That’s critical, Stackhouse-Lawson said, because the research will contribute to the cattle industry’s understanding of baseline emissions at a population level; this allows for more accurate modeling of enteric methane. Modeling, in turn, is pivotal in managing and auditing enteric emissions – the crux of understanding how the industry is doing.

“It’s a new frontier,” Tony Bryant, director of nutrition, research and analytics for Five Rivers Cattle Feeding, said of challenges and opportunities in the realm of cattle methane emissions. Five Rivers Cattle Feeding, headquartered in Johnstown, in Northern Colorado, is the world’s largest cattle feeder and is a frequent partner of AgNext; it often supplies the CSU research group with cattle used in methane research.

“We feel like we have good practices to reduce greenhouse gas emissions, but we’ve got to figure out baseline emissions,” said Bryant, who earned a doctorate from CSU in ruminant nutrition and metabolic physiology. “We’ve got to quantify the greenhouse gases we are producing so we can determine our impact over time, evaluate the usefulness of new technologies and practices, and understand if and how we can help those wanting to offset carbon emissions through carbon credit markets in a move toward carbon neutrality.”

Stackhouse-Lawson discussed AgNext research while observing cattle at CSU’s Climate Smart Research Facility. The facility and the research conducted there are supported by some of the biggest names in agriculture, including Five Rivers, Cargill, Dairy MAX and Merck Animal Health. AgNext research is also funded by the U.S. Department of Agriculture.

Here, in a study led by Sara Place, an associate professor of animal sciences, researchers use specialized technology to monitor how feed additives affect the quantity of methane produced by 250 feedlot steers. Place and her team track precise feed intake, then entice steers into a hooded feed bunk using alfalfa pellets as treats. As the animals munch, equipment analyzes and records enteric gas output with each “burping event,” which occurs about every minute.