Removal of dairy cows from the United States may reduce essential nutrient supply with little effect on greenhouse gas emissions

American Dairy Science Association® Ken Olson, PhD, PAS

Research in the Journal of Dairy Science® examines the potential impact of various animal removal assumptions on the environment and nutritional supplies

A new study published in the Journal of Dairy Science suggests that the removal of dairy cattle from US agriculture would only reduce greenhouse gas emissions by 0.7 percent and lower the available supply of essential nutrients for the human population. Photo: iStock.com/singkamc

The US dairy industry contributes roughly 1.58 percent of the total US greenhouse gas emissions; however, it also supplies the protein requirements of 169 million people, calcium requirements of 254 million people, and energy requirements of 71.2 million people. A suggested solution to increasing food production worldwide while reducing greenhouse gas emissions has been to eliminate or reduce animal production in favor of plant production. In an article appearing in the Journal of Dairy Science, scientists from Virginia Tech and the US Dairy Forage Research Center studied the effects of dairy product removal on greenhouse gas emissions and nutrient availability in US diets under various removal scenarios.

The authors of this study assessed three removal scenarios—depopulation, current management (export dairy), and retirement. In depopulation, consumers would stop consuming dairy products, resulting in depopulation of the animals; in current management (export dairy), the cattle management would remain the same and milk produced would be used for products other than human food or exported for human consumption; in retirement, the cattle would be retired to a pasture-based system but reduced to numbers that could be supported by available pastureland.

“Land use was a focus in all animal removal scenarios because the assumptions surrounding how to use land made available if we remove dairy cattle greatly influence results of the simulations,” said lead investigator Robin R. White, PhD, Department of Animal and Poultry Science, Virginia Tech, Blacksburg, VA, USA. “If dairy cattle are no longer present in US agriculture, we must consider downstream effects such as handling of pasture and grain land previously used for producing dairy feed, disposition of byproduct feeds, and sourcing fertilizer.”

Greenhouse gas emissions were unchanged in the current management (export dairy) scenario, with a decrease in nutrient supplies, as expected. Emissions declined 11.97 percent for the retired scenario and 7.2 percent for the depopulation scenario compared to current emissions. All 39 nutrients considered in human diet quality were decreased for the retired scenario, and although 30 of 39 nutrients increased for the depopulation scenario, several essential nutrients declined.

The results of the study suggest that the removal of dairy cattle from US agriculture would only reduce greenhouse gas emissions by 0.7 percent and lower the available supply of essential nutrients for the human population.

Professor White added, “Production of some essential nutrients, such as calcium and many vitamins, decreased under all reallocation scenarios that decreased greenhouse gas emissions, making the dairy removal scenarios suboptimal for feeding the US population.”

This study illustrates the difficulties in increasing supplies of critically limiting nutrients while decreasing greenhouse gas emissions.

About the Journal of Dairy Science

The Journal of Dairy Science® (JDS), an official journal of the American Dairy Science Association®, is co-published by Elsevier and FASS Inc. for the American Dairy Science Association. 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 2019 Journal Impact Factor of 3.333 and 5-year Journal Impact Factor of 3.432 according to Journal Citation Reports (Source: Clarivate 2020). 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

About Elsevier

Elsevier is a global information analytics business that helps scientists and clinicians to find new answers, reshape human knowledge, and tackle the most urgent human crises. For 140 years, we have partnered with the research world to curate and verify scientific knowledge. Today, we’re committed to bringing that rigor to a new generation of platforms. Elsevier provides digital solutions and tools in the areas of strategic research management, R&D performance, clinical decision support, and professional education; including ScienceDirect, Scopus, SciVal, ClinicalKey, and Sherpath. Elsevier publishes over 2,500 digitized journals, including The Lancet and Cell, 39,000 e-book titles and many iconic reference works, including Gray’s Anatomy. Elsevier is part of RELX, a global provider of information-based analytics and decision tools for professional and business customers.





www.elsevier.com

About FASS Inc.

Since 1998, FASS has provided shared management services to not-for-profit scientific organizations. With combined membership rosters of more than 10,000 professionals in animal agriculture and other sciences, FASS offers clients services in accounting, membership management, convention and meeting planning, information technology, and scientific publication support. The FASS publications department provides journal management, peer-review support, copyediting, and composition for this journal; the staff includes five BELS-certified (www.bels.org) technical editors and experienced composition staff. www.fass.org

The article is “Contributions of dairy products to environmental impacts and nutritional supplies from United States agriculture,” by D.L. Liebe, M.B. Hall and R.R. White (https://doi.org/10.3168/jds.2020-18570). It appears in advance of the Journal of Dairy Science, volume 103, issue 11 (November 2020), published by FASS Inc. and Elsevier





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