Growing Beef Newsletter
September 2025, Volume 16, Issue 3
Methods for measuring methane emissions and use for genetic improvement in beef cattle
Jaedyn Condon, Animal Breeding and Genetics graduate student, Iowa State University
In recent years, the term greenhouse gas has been very prominent in the United States beef cattle industry, with methane being the biggest concern. Methane is the second largest greenhouse gas produced behind carbon dioxide and has continued to rise, accounting for approximately 11% of the total greenhouse gas emissions. Methane is produced by all ruminant animals through enteric fermentation, with 25% of methane emissions coming from enteric fermentation from cattle and other ruminant animals shown in Figure 1. This percentage has increased and decreased over the years due to fluctuating cattle populations and changes in contributions from other methane sources. Even though this seems like a small amount, some producers are seeing what they can do to help decrease the methane emissions from their cattle. Being able to decrease methane emissions will not only benefit the environment but also producers. Methane is lost energy that could be going towards pounds of gain. The more methane the cow produces, the more energy that is wasted. If we can lower methane emissions, it can help with sustainability as well as help producers become more profitable by cattle using feed resources toward gain instead of waste.
The first step to reducing methane emissions is being able to measure it. There are several different methods that allow methane production to be evaluated in cattle. These methods all have their strengths and weaknesses that go along with different production goals.
One of the most well-known methods for measuring methane is through a respiration chamber. The cow goes into the enclosed chamber for a certain amount of time, where it captures all the methane being emitted from both the mouth and rectum. This method is known for being very reliable and accurate. The downside is that the cow is in a new environment that may cause stress and interrupt typical habits.
The sulfur hexafluoride tracer is another common method for collecting methane and works by inserting a permeation tube in the reticulum of the cow, releasing a tracer gas (SF₆) at a certain rate. All of the air coming out of the cow's nose goes to a canister through a halter that is attached by tubing. The amount of methane and tracer gas concentrations is then compared to estimate methane production. This method can be used on a large number of cattle in their normal environment, but it only accounts for methane coming from the nostrils of the cow.
The Greenfeed system collects methane emissions from cattle using a feeder. The Greenfeed distributes a small amount of bait to attract cattle to come eat at the feeder. While they are at the Greenfeed eating, gases are taken to sensors that measure methane. This method measures methane in grams per day and can collect data in a shorter period. It also allows them to be measured in their normal environment; however, some cattle take time to adjust to the feeder or may not be interested in the bait.
All of these methods have advantages and disadvantages to how they work and the data that they collect. We can use these methods to gather phenotypic data that we can use to conduct genetic evaluations. Research has shown that the heritability of methane emissions is moderately heritable and ranges from 0.19 to 0.29. This means that we can select for lower emissions in cattle, which can help reduce methane emissions and help producers get closer to their goals for production and the environment. Since methane is a natural byproduct of fermentation, we need to be mindful of what we are doing when selecting for lower emissions to ensure we are not inadvertently decreasing productivity of the cattle. Overall, collection methods can be very useful in understanding methane emissions and using them for genetic selection.
References
Elizabeth A Dressler, Jennifer M Bormann, Robert L Weaber, Megan M Rolf, Use of methane production data for genetic prediction in beef cattle: A review, Translational Animal Science, Volume 8, 2024, txae014.
EPA (2024) Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2022. U.S. Environmental Protection Agency, EPA 430-R-24-004 Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2022.
Ghassemi Nejad, Jalil, et al. “Advances in methane emission estimation in livestock: A review of data collection methods, model development and the role of AI Technologies.” Animals, vol. 14, no. 3, 29 Jan. 2024, p. 435.
“GreenFeed - Measure Large Ruminant Emissions.” C-lock. Accessed 21 Aug. 2025.
Hayes, B. J., et al. “Genomic Heritabilities and genomic estimated breeding values for methane traits in Angus Cattle1.” Journal of Animal Science, vol. 94, no. 3, 1 Mar. 2016, pp. 902–908.
Luke, Jaime R., and Glynn T. Tonsor. "The Enteric Methane Emission Conundrum: U.S. Beef Cattle Producer Adoption of Climate-Focused Technology." Sustainable Production and Consumption, vol. 50, 2024, pp. 364–375. Elsevier.
“Methane Emissions.” EPA, Environmental Protection Agency, 31 Mar. 2025.
“Overview of Greenhouse Gases.” EPA, Environmental Protection Agency, 3 Mar. 2025.
Pfau, Alison. “How Can We Measure Methane Emissions from Commercial Farms?” Accessed 21 Aug. 2025.
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