Henry Emmerich, MJLST Staffer
The fight against climate change is ongoing, strenuous, and full of misinformation. Critics claimed that supporters of legislation to address climate change “want to take out the cows.”[1] While this statement was false, there is some truth to the underlying idea. The cattle industry emits methane on an astronomical scale.[2]
Current Environmental Impact of Cattle
Livestock, such as cows, “produce methane (CH4) as part of their normal digestive processes. This process is called enteric fermentation, and it represents over a quarter of the emissions from the agriculture economic sector.”[3] On average, one cow “burps” 220 pounds of methane each year.[4] As of July 1, 2025, there were 94.2 million cattle on U.S. farms.[5]
Methane is the second largest contributor to global warming after carbon dioxide.[6] Pound for pound, however, methane has a warming impact eighty-six times higher than carbon dioxide.[7] Good news: methane remains in the atmosphere for only twelve years, compared to carbon dioxide which can stay in the atmosphere well beyond 300 years.[8] Methane’s strong warming effect and relatively short lifetime mean that curbing methane emissions is a potentially effective way to significantly reduce atmospheric warming within a few decades. Because methane is produced naturally during a cow’s digestive process, changing what cattle eat is a relatively straightforward means to reduce emissions from an industry that is currently the largest human-derived source of methane emissions.[9]
Climate Friendly Cattle Feed
Feed additives may reduce livestock methane emissions.[10] Red seaweed, Asparagopsis armata (AA) and Asparagopsis taxiformis (AT), are two such additives. Researchers are studying the effects of red seaweed consumption on feedlot cattle, dairy cows, and grazing cattle.[11] A 2021 study looking at feedlots operations in which cows are confined in fenced areas to maximize weight gain before slaughter found, “Cattle that consumed doses of about 80 grams (3 ounces) of seaweed gained as much weight as their herd mates while burping out 82 percent less methane into the atmosphere.”[12] In dairy cows, there was over a 50% reduction in methane emissions following the introduction of a red seaweed supplement to the cows’ diet.[13] Finally, adding red seaweed to the diet of grazing cattle reduced their methane emissions by nearly forty percent.[14] Due to the roaming nature of grazing cattle, it is difficult to create a controlled environment where a study can be easily conducted. Researchers therefore allowed the experiment group of cattle to voluntarily consume the supplement over a ten-week period.[15] If researchers develop a method to more reliably induce consumption of seaweed in grazing cattle, the effect could be even more significant.
How does AT reduce methane emissions? The effect lies in the rumen (the largest compartment of a cow’s stomach), Methanosphaera, and bromoform.[16] Methanosphaera is a microbe in the rumen that uses hydrogen to break methanol down into methane, an AT supplement led to a “near total elimination of Methanosphaera.”[17] Bromoform is a substance that is found in AT and inhibits certain enzymes utilized by Methanosphaera to produce methane.[18]
Current Legislation
While the Inflation Reduction Act allocated billions of dollars into renewable energy, lawmakers failed to meaningfully address a massive source of methane emissions: cattle.[19] The Federal government will pay farmers to voluntarily address climate change; however, most cattle eat a majority corn diet.[20] Federal regulations of animal food on prevent contamination and regulate what drugs can be included in medicated feed.[21]
States focus regulations of animal feed on informing consumers, preventing contamination, and licensing manufacturers.[22] All 50 states have some amount of cattle within their borders; however, only thirteen states account for nearly two-thirds of cattle in the United States.[23] If these thirteen states were to regulate what farmers and ranchers were feeding their cows, methane emissions would be curbed significantly. The FDA categorizes these additives as livestock drugs and must approve them prior to implementation.
Challenges Going Forward
Going forward, there are challenges to the development and eventual adoption of red seaweed or bromoform supplements being used in cattle feed. Uncertainty over how to classify products derived from red seaweed has stalled development in the United States. Bromoform is plagued by regulatory hurdles because is it classified as a “probable human carcinogen” by the Environmental Protection Agency[24] In high doses bromoform can pass into the milk and meat of cows who consume it, fortunately the amount of bromoform necessary to obtain methane reduction in livestock is less than one percent of the amount which could be harmful to humans.[25]
Momentum is building; California approved funds to the development of methane inhibitors related to cattle.[26] The FDA approved a Dutch product containing 3-NOP, a less effective methane inhibitor, as a livestock drug.[27] The “Innovative FEED Act of 2025” was introduced in the House of Representatives where it currently awaits further action.[28] A federal framework would be helpful to hasten development and adoption of methane inhibitors. States, however, retain certain power over livestock feed.[29] Hopefully, collaboration between federal and state lawmakers can clear the way for massive reductions in agricultural methane emissions.
Notes
[1] Carlyn Kranking & Grace Rodgers, Trump Warns the Green New Deal Will ‘Take Out the Cows.’ Here’s the Science Showing Why That’s a Myth, Nw. Climate Change (Nov. 19, 2020) https://climatechange.medill.northwestern.edu/trump-warns-the-green-new-deal-will-take-out-the-cows-heres-the-science-showing-why-thats-a-myth/.
[2] See generally Anna Obek, Comment, Cow Methane-Reduction Wearable Technology and Animal Welfare: Humane Solutions to Lessen Livestock’s Environmental Impact, 101 Or. L. Rev. 479 (2023).
[3] Sources of Greenhouse Gas Emissions, U.S. Env’t Prot. Agency, https://www.epa.gov/ghgemissions/sources-greenhouse-gas-emissions#agriculture [https://perma.cc/3325-7LY2] (last visited Feb. 25, 2026).
[4] Amy Quinton, Cows and Climate Change, UC Davis (June 27, 2019), https://www.ucdavis.edu/food/news/making-cattle-more-sustainable [https://perma.cc/AA7H-NEMW].
[5] USDA, United States Cattle Inventory Report (July 25, 2025), https://www.nass.usda.gov/Newsroom/2025/07-25-2025.php.
[6] Climate & Clean Air Coalition, Methane, https://www.ccacoalition.org/short-lived-climate-pollutants/methane (last visited Feb. 25, 2026).
[7] Id.
[8] Id.
[9] Id.
[10] Methane Emissions Are Driving Climate Change. Here’s How to Reduce Them., U.N. Env’t Programme (Aug. 20, 2021), https://www.unep.org/news-and-stories/story/methane-emissions-are-driving-climate-change-heres-how-reduce-them.
[11] Amy Quinton, Feeding Grazing Cattle Seaweed Cuts Methane Emissions by Almost 40%, UC Davis (Dec. 2, 2024), https://www.ucdavis.edu/food/news/feeding-grazing-cattle-seaweed-cuts-methane-emissions-almost-40.
[12] Diane Nelson, Feeding Cattle Seaweed Reduces Their Greenhouse Gas Emissions 82 Percent, UC Davis (Mar. 17, 2021), https://www.ucdavis.edu/climate/news/feeding-cattle-seaweed-reduces-their-greenhouse-gas-emissions-82-percent.
[13] Quinton, supra note 11.
[14] Id.
[15] Id.
[16] See id.; Erica Moser, Understanding How a Red Seaweed Reduces Methane Emissions From Cows, Penn Today (July 19, 2024), https://penntoday.upenn.edu/news/penn-vet-understanding-how-red-seaweed-reduces-methane-emissions-cows.
[17] Id.
[18] See generally Gyeltshen et al., Feeding a Bromoform-Based Feed Additive for Methane Mitigation in Beef Cattle, J. ANIMAL Feed Sci. & Tech. 326 (2025).
[19] See U.S. Dep’t of Agric., Accelerating Climate Solutions on Livestock Operations Through the Inflation Reduction Act, Usda (May 2024), https://www.nrcs.usda.gov/sites/default/files/2024-05/202405-NRCS-FactSheet-IRA_LivestockOperations.pdf.
[20] McKenzie Mak, What Do Cows Eat? Natural Diet vs. Factory Farm Feed Explained, World Animal Protection U.S. (Sept. 13, 2024), https://www.worldanimalprotection.us/latest/blogs/what-do-cows-eat/.
[21] See FDA, Animal Food Regulations, https://www.fda.gov/animal-veterinary/animal-health-literacy/animal-food-regulations (last visited Feb. 25, 2026); FDA, FDA’s Regulation of Pet Food, https://www.fda.gov/animal-veterinary/animal-health-literacy/fdas-regulation-pet-food (last visited Feb. 25, 2026); FDA, FDA Regulation of Medicated Feed, https://www.fda.gov/animal-veterinary/resources-you/fda-regulation-medicated-feed (last visited Feb. 25, 2026).
[22] See e.g., Tex. Admin. Code §§ 61.001–61.019 (2019); K.S.A. “The Kansas Commercial Feeding Stuffs Law” (2011); Minn. Stat. 25.31, “Minnesota Commercial Feed Law” (2025).
[23] Rob Cook, Ranking of States with the Most Cattle, Nat’l Beef Wire, https://www.nationalbeefwire.com/ranking-of-states-with-the-most-cattle-texas-leads-the-herd (last visited Feb. 25, 2026).
[24] Swati Hegde, Cutting Cattle Methane Through Feed Additives: Lessons from Early Adoption and the Road Ahead, World Resources Institute (June 17, 2025), https://www.wri.org/technical-perspective/cattle-methane-inhibitors-early-adoption-next-steps#:~:text=Adoption%3A%20Not%20yet%20approved%20for%20use%2C%20though%20several%20pilot%20trials%20are%20underway%20in%20Australia%2C%20the%20EU%20and%20the%20U.S.
[25] Id.
[26] Colton Fagundes, Senate Resolution Introduced to Provide Principled Framework to Address Enteric Methane Emissions in California’s Dairy and Livestock Sector, Cal. Climate & Agric. Network (May 27, 2025), https://calclimateag.org/california-dairy-methane-solutions/.
[27] Id.
[28] See H.R. 2203, 199th Cong. (2025–2026).
[29] See Cook supra note 23.