Advances in dairy nutrition science may be able to deliver a 60% reduction in enteric methane emissions in the coming years, according to a new Journal of Dairy Science® invited review
Philadelphia, August 6, 2024 – Research into reducing greenhouse gas emissions from livestock has exploded as the dairy and agriculture sectors all work toward shared sustainability and efficiency goals. While this progress has been made in all areas of dairy science research, from genetics to animal health and welfare, dairy nutrition has emerged as a particularly impactful area for emission reduction. In a new invited review in the Journal of Dairy Science, a preeminent voice in sustainability and dairy nutrition synthesizes what we know so far and reveals that new nutrition strategies could potentially slash methane emissions by a staggering 60% in the coming years.
Methane (both enteric methane produced during digestion and methane from manure) is the critical greenhouse gas that makes up most of the dairy industry’s environmental footprint. The invited review’s author, Alexander Hristov, PhD, PAS, a distinguished professor of dairy nutrition at The Pennsylvania State University and editor of Advances in Sustainable Dairy Cattle Nutrition, explained, “There are two main ways to tackle enteric methane emissions through nutrition: adjusting an animal’s diet or adding in specific new ingredients.” Hristov set out to provide a helpful overview of what we know now about both options, where additional research is needed, and which methane-reduction pathways might be most practical and achievable for the future.
The article begins with the latest findings on diet reformulation, including adjusting concentrate feeds, feeding corn versus grass and legume silage, and using alternative forages such as sorghum or plantain. With all of these options available, can diet changes have a real impact on methane emissions? The answer, asserts Hristov, isn’t simple or one size fits all.
“Diet reformulation depends on a farm’s unique scenario to be an effective tool,” says Hristov. “If a dairy has room for efficiency and productivity improvements, for example, balancing diets can be helpful.” However, this approach is less practical in intensive dairy production systems, where nutritional professionals formulate the diets and producers have efficiency dialed in. In those dairy systems, Hristov explains, “It may be difficult to find specific feeds that can have a substantial and measurable impact on methane emissions.”
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Caption: Advances in dairy nutrition and feed additives are unlocking a lower methane footprint for the dairy sector (Credit: iStock.com/ PixelCatchers)
That leaves feed additives: new ingredients supplemented in small amounts to a dairy cow’s existing diet to reduce methane produced during digestion. Based on existing research, the most promising additives are seaweeds and 3-nitrooxypropanol (3-NOP).
Red seaweed varieties, for example, contain bromoform, an active compound that has been effective at reducing methane emissions in several studies. “Bromoform appears to be able to achieve a 30% to 50% emissions reduction, but whether this effect can be applied broadly and consistently needs more research,” explained Hristov.
The strongest feed additive contender to emerge is 3-NOP. “Its efficacy has been proven in numerous controlled and independent experiments, and 3-NOP is currently the only available option headed to market for dairy operations looking to use additives to reduce emissions,” said Hristov.
Hristov also highlighted two areas that could benefit from more research as dairy works to move the sustainability needle forward: reducing methane emissions from cow manure, and studying whether nutrition strategies can be paired together synergistically. “In theory, practices with different modes of reducing methanogens could work together to boost overall mitigation,” said Hristov. The article cites a best-case scenario in the literature in which a 20% to 30% reduction by a feed additive could be paired with another 10% to 20% reduction from a second feed additive, plus, perhaps, another 5% to 10% from improvements in forage quality and diet manipulation, adding up to a substantial overall impact in lowering methane.
While Hristov was clear that the pathways toward dairy sustainability are still in flux—and that no one solution will work for every dairy system and every farm—advances in dairy nutrition will be an essential component in the methane-reduction mix. “If currently available mitigation practices prove to deliver consistent results,” explained Hristov, “and novel, potent, and safe strategies are discovered, nutrition alone can deliver up to a 60% reduction in enteric methane emissions and pave the way for a more sustainable dairy sector.”
Notes for editors
The article is “Invited review: Advances in nutrition and feed additives to mitigate enteric methane emissions,” by Alexander N. Hristov (https://doi.org/10.3168/jds.2023-24440). It appears in the Journal of Dairy Science, volume 107, issue 7 (July 2024), published by the American Dairy Science Association and Elsevier.
The article is openly available at https://www.journalofdairyscience.org/article/S0022-0302(24)00910-X/fulltext and the PDF version is available at https://www.journalofdairyscience.org/action/showPdf?pii=S0022-0302%2824%2900910-X.
Full text of this article is also available to credentialed journalists upon request; contact Eileen Leahy at +1 732 406 1313 or jdsmedia@elsevier.com. Journalists wishing to interview the author should contact Alexander N. Hristov, PhD, PAS, of the Department of Animal Science, The Pennsylvania State University, University Park, PA at anh13@psu.edu.
About the Journal of Dairy Science
The Journal of Dairy Science® (JDS), an official journal of the American Dairy Science Association® (ADSA), is co-published by Elsevier and ADSA. It is the leading general dairy research journal in the world. JDS readers represent education, industry, and government agencies in more than 70 countries, with interests in biochemistry, breeding, economics, engineering, environment, food science, genetics, microbiology, nutrition, pathology, physiology, processing, public health, quality assurance, and sanitation. JDS has a 2022 Journal Impact Factor of 3.5 and five-year Journal Impact Factor of 4.2 according to Journal Citation Reports™ (Source: Clarivate™ 2023). www.journalofdairyscience.org
About the American Dairy Science Association (ADSA®)
The American Dairy Science Association (ADSA) is an international organization of educators, scientists, and industry representatives who are committed to advancing the dairy industry and keenly aware of the vital role the dairy sciences play in fulfilling the economic, nutritive, and health requirements of the world’s population. It provides leadership in scientific and technical support to sustain and grow the global dairy industry through generation, dissemination, and exchange of information and services. Together, ADSA members have discovered new methods and technologies that have revolutionized the dairy industry.www.adsa.org
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