Dairy Sustainability – The Jargon, the Dairy Story, and the Opportunity (Part I)

Dr. Kirby Krogstad, Assistant Professor, Department of Animal Sciences, The Ohio State University and Dr. Joanne Knapp, Fox Hollow Consulting, LLC

Everyone wants to talk about carbon, but who is going to do anything about it? Dairy farmers and allied dairy industry partners are stepping up to the plate! They’ve been investing in and researching new strategies that will shrink our greenhouse gas footprint while also returning value to the farm-gate. This article series aims to get us on the same page about the dairy system and its sources of greenhouse gas emission, about the emerging technologies that will enable us to reduce enteric methane emissions from cattle, and discuss what carbon credits are, how they are being bought and sold, and what that means for the dairy farms and the dairy industry.

First, we need to get some context on the dairy carbon story and the current dairy carbon emissions picture.

How Much Carbon Does the U.S. Dairy Industry Emit?

“Carbon” is actually carbon dioxide equivalents (CO2e). Carbon dioxide, methane, and nitrous oxide are the three major contributors of CO2e. In total, its estimated that man-made activities in the US emit about 6,300 million metric tons of CO2e each year. Of that, dairy production accounts for 139 million metric tons, or about 2% of the total emission (Figure 1). Although we’re a relatively small emitter relative to other US sectors, if the US dairy sector were its own country, it would rank in the top 1/3 of all countries on a total emission basis. We mustn’t shirk our responsibility – and we’re not!

Figure 1. United States Greenhouse Gas inventory. Dairy cattle comprise 2% of total USA emissions. Data from epa.gov.

The Dairy Industry’s Commitment: What Does “Net-zero” Mean?

Companies, organizations, and governments are making sustainability commitments left and right; The US dairy industry is no different. The Innovation Center for US dairy has committed to achieving “greenhouse gas neutrality” by 2050 – what does that mean?

Being greenhouse neutral, as US Dairy has committed itself, is defined as the point where anthropogenic (from human activity) emissions are balanced by anthropogenic removal. This is a very difficult mark to achieve, but a worthy task nonetheless. Another common benchmark is climate neutrality; climate neutral means that human activities have no net-effect on the climate system; some have described this as being equivalent to “warming neutral” or not adding to warming of the globe.  Fortunately, the dairy industry is within striking distance of climate neutrality. Place et al. (2022) determined that a 23% reduction in farm-gate emissions for US dairy farms will mean that dairy farms no longer add to the warming of the climate. If we go beyond 23% reduction means we’re really part of the solution!

Reaching greenhouse gas neutrality may prove to be more difficult and will most certainly require soil carbon sequestration or alternative methods of atmospheric carbon removal. One way to inch toward this goal of greenhouse gas neutrality is the use of methane mitigating feed additives. Incentives are coming into view for such a practice to have an economic return, but we will cover both methane mitigating feed additives and the carbon markets associated with them over the next couple of articles.

The Dairy Story: What are the Sources of Emissions on a Dairy Farm?

So where do dairy farm emissions come from? The major sources of greenhouse gas emissions on most dairy farms are manure methane and nitrous oxide emissions (33%), enteric methane emissions (35%), feed production (26%), and energy use (6%; Figure 2). Of course, this can vary tremendously from farm to farm. A farm’s greenhouse gas footprint is especially dependent on the manure management practices and feed efficiency of the whole herd. For example, capturing methane from manure using anaerobic digestion reduces the greenhouse gas emissions from manure by 50%. Solid separation technologies can also reduce the greenhouse gas emissions from manure by 20% (Aguirre-Villegas et al., 2014).

Figure 2. Greenhouse gas emission sources for U.S. dairy farms. Adapted from usdairy.com.

Opportunities: What Do These Sustainability Initiatives Mean for the Future (or the present)?

Sustainability commitments and initiatives are here to stay. Fortunately, the dairy industry has an encouraging story to tell. Some dairy farms are already using manure methane to fuel cars and power buildings. Some electric cars are even being juiced up on dairy cow manure! Reduced and no-till cropping practices have improved soil carbon sequestration. Over the past two decades, genetic selection for yield of milk components, along with supporting approaches in forage selection and harvesting, herd health, parlor technologies, and feeding management, have reduced emissions intensity. Combined, these strategies reduced the carbon footprint of milk by 19% from 2007 to 2017 (Capper and Cady, 2019).

The emerging opportunity for dairy farms to continue enhancing their sustainability is through the use of enteric methane reducing feed additives. There’s plenty of promise along with challenges – we’ll chat about those next time….


Aguirre-Villegas, H. A., R. Larson, and D. J. Reinemann. 2014. From waste-to-worth: energy, emissions, and nutrient implications of manure processing pathways. Biofuels, Bioproducts and Biorefining 8(6):770-793. https://doi.org/10.1002/bbb.1496

Capper, J. L., and R. A. Cady. 2019. The effects of improved performance in the U.S. dairy cattle industry on environmental impacts between 2007 and 2017. J. Anim. Sci. 98(1). https://doi.org/10.1093/jas/skz291

Place, S. E., C. J. McCabe, and F. M. Mitloehner. 2022. Symposium review:Defining a pathway to climate neutrality for US dairy cattle production. J. Dairy Sci. 105(10):8558-8568. 10.3168/jds.2021-21413.