Organic and Conventional Milk – Comparing Apples to Apples?

Review of published research reveals inconsistencies in comparisons of organic and conventional milk according to new Journal of Dairy Science® study

Philadelphia, PA, January 20, 2015

Consumers perceive that organic cow milk differs from conventionally produced milk and that these differences justify the premium price for organic milk. In a review published in the Journal of Dairy Science®, researchers in New Zealand found that the differences between organic and conventional milk are not so straightforward.

Reviewing almost 200 publications, researchers concluded that previously conducted controlled studies investigating whether differences exist between organic and conventionally produced milk have so far been largely ambiguous, due principally to the complexity of the research question and the number of factors and variables that can influence milk composition. "This review presents one of the most detailed treatises to date of organic versus conventional milk composition," commented Matt Lucy, PhD, Professor of Animal Science, University of Missouri, and Editor-in-Chief of the Journal of Dairy Science®.

"When comparing organic and conventional milk composition (especially milk fatty acids), previous studies have generally compared organic dairying with milk produced from grass-fed cows to conventional dairying with milk produced from concentrate-fed cows. The differences in milk composition observed are actually due to the different diets of the cows (i.e. pasture versus concentrate feeding) rather than organic versus conventional farming systems," according to lead investigator Don Otter, PhD, Senior Scientist, Food & Bio-based Products, AgResearch Grasslands Research Centre (New Zealand).

Because there are many factors that affect milk composition, it is difficult to control for all of them when comparing organic to conventional milk production. According to the investigators, "The term 'organic' when applied to dairying is not universal, and to a large extent, is defined simply by regulations that differ from one country to the next. 'Conventional' basically is anything that is not 'organic.' However, in most parts of the world, conventional dairying is associated with high levels of grain feeding, the use of cow breeds which produce high milk volumes, and the application of large amounts of fertilizer ('high input' farming), while organic dairying is tied to pasture and forage feeding, lower amounts of fertilizer application, and the use of mixed or minority breeds ('low input'). The vast majority of differences reported between organic and conventional milk come from what cows are fed and their breed, and is not anything unique to being organic or conventional in itself."

Therefore in terms of nutrients in milk, there is nothing distinct about organic milk that makes it unique from conventionally produced milk once the different factors that influence milk production are compared or adjusted for. If animal genetics, health, breed, diet, management, or environment differs, then so will the composition of the milk produced.


Notes for editors
"Organic and conventionally produced milk—An evaluation of factors influencing milk composition," by B.H. Schwendel, T.J. Wester, P.C.H. Morel, M.H. Tavendale, C. Deadman, N.M. Shadbolt, and D.E. Otter. Journal of Dairy Science, Volume 98, Issue 2,, published by Elsevier.

Full text of this article is available to credentialed journalists upon request. Contact Eileen Leahy at +1 732 238 3628 or to obtain copies. Journalists wishing to set up interviews with the authors should contact Don Otter at +64 212 853 894 or

About Journal of Dairy Science®
Journal of Dairy Science (JDS), official journal of the American Dairy Science Association, is co-published by Elsevier and the Federation of Animal Science Societies 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 is ranked number 2 in the Agriculture, Dairy and Animal Science category of the 2013 Journal Citation Reports®, published by Thomson Reuters, with a 5-year Impact Factor of 3.080.

About the American Dairy Science Association (ADSA)
The American Dairy Science Association (ADSA), a member of the Federation of Animal Science Societies (FASS), 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.

About Elsevier
Elsevier is a world-leading provider of information solutions that enhance the performance of science, health, and technology professionals, empowering them to make better decisions, deliver better care, and sometimes make groundbreaking discoveries that advance the boundaries of knowledge and human progress. Elsevier provides web-based, digital solutions — among them ScienceDirect, Scopus, Research Intelligence and ClinicalKey— and publishes over 2,500 journals, including The Lancet and Cell, and more than 35,000 book titles, including a number of iconic reference works. Elsevier is part of RELX Group, a world-leading provider of information and analytics for professional and business customers across industries.

Media contact
Eileen Leahy
+1 732 238 3628

Ken Olson, PhD, PAS
American Dairy Science Association®
+1 630 237 4961