Farm-Specific Data Cuts Milk’s Carbon Footprint by 27 Percent in Bangladesh Study

Every kilogram of milk that reaches a breakfast table carries an invisible environmental price tag, a figure scientists call the carbon footprint. Calculating that number accurately is far harder than it sounds, particularly in countries where dairy farming looks nothing like the industrialized systems of North America and Europe. A new study from the laboratory of Elias Uddin, assistant professor of animal science in the University of Connecticut’s College of Agriculture, Health and Natural Resources, has now demonstrated just how much difference the right data and the right equations can make. Working with collaborators at Bangladesh Agricultural University, the team produced what it describes as a more accurate measure of the carbon footprint of milk produced in Bangladesh, and the results, published in the Journal of Dairy Science, challenge long-standing assumptions about the climate cost of dairy in developing countries.

The research rested on five years of detailed records collected from the Bangladesh Agricultural University Dairy Farm between 2018 and 2023. Rather than relying on broad regional averages, Uddin’s laboratory mined this farm-specific dataset to calculate emissions across every major stage of production. The analysis covered the fertilizer applied to grow cattle feed, the enteric emissions generated by the cows’ own digestive processes, the handling and management of manure, and the energy consumed in running the farm itself. This granular approach follows the logic of life cycle assessment, the standard framework used to quantify the environmental impact of a product from its earliest inputs onward.

The breakdown of emission sources proved revealing. Enteric fermentation, the natural digestive process by which cattle break down fibrous feed and release methane in the process, accounted for 48 percent of the farm’s total emissions, nearly half of everything the operation produced. Feed production came next at 24 percent, followed by manure management at 20 percent, with energy used to power the farm contributing the remaining 8 percent. These proportions matter because they tell researchers and farmers where mitigation efforts will pay the greatest dividends. In a system dominated by enteric emissions, improving what and how efficiently cows eat can ripple through the entire footprint calculation.

One methodological detail proved especially important. Under standard life cycle assessment guidelines, the team included not only the lactating cows that actually produce milk but also the non-lactating members of the herd, including young and dry animals that consume resources without yielding any milk. You have to account for those non-lactating animals, because those are part of the production system, Uddin explains. You cannot just avoid them because they don’t produce milk. Excluding these animals would artificially deflate the footprint of each liter of milk, since their feed, digestion, and manure emissions would vanish from the ledger while their contribution to the herd’s future productivity remained.

The headline number from the study is striking. On average, across the five-year period, the carbon footprint of milk on the farm was 5.18 kilograms of carbon per kilogram of milk, a measure of how many kilograms of carbon are required to produce a single kilogram of milk. That figure sits far above the roughly 1 kilogram of carbon emission per kilogram of milk typical of American and European dairy farms, and it aligns with previous work holding that dairy production in southeast Asia carries a much heavier climate burden. But the reasons behind that gap, and the way it should be measured, turned out to be more complicated than the raw numbers suggest.

A central finding concerns the choice of calculation method. Previous estimates for the region relied on the Tier 1 equations proposed by the Intergovernmental Panel on Climate Change, which apply generalized emission factors across broad categories of livestock systems. Uddin’s team instead used the more refined Tier 2 equations from the same body, which incorporate farm-specific data on animal characteristics and management. The result was a carbon footprint 27 percent lower than earlier estimates based on the generalized Tier 1 approach. In other words, a substantial share of the apparent climate penalty assigned to Bangladeshi dairy appears to be an artifact of coarse measurement rather than a true feature of the production system.

Productivity emerged as the single most powerful lever. Over the five-year study period, the productivity of the cows increased by 63 percent, which drove a 37 percent reduction in the carbon footprint over time. In 2018, the cows on the farm produced an average of 3.53 kilograms of milk per day. By 2023, that figure had climbed to 5.76 kilograms on average. The gains came from genetic selection and improved management strategies, including balanced diets and more efficient feed management. Because a more productive cow spreads the fixed emissions of maintaining an animal across more units of milk, every additional liter dilutes the footprint per kilogram. We saw that increasing productivity is really a crucial thing, and very important to reduce the carbon footprint, Uddin says. In developing countries, increasing efficiency and productivity is key to reducing carbon footprint rather than hitting only emissions mitigation strategies.

The structure of Bangladeshi agriculture adds another layer of complexity that conventional carbon accounting struggles to capture. In Bangladesh, cattle farms raise animals for both dairy and meat together, a dual-purpose system. In the United States, by contrast, dairy and beef production are usually separate operations. Applying the same emission allocation equation to both systems is therefore not accurate. Only about 50 percent of emissions on a cattle farm in Bangladesh go toward milk production, a process called emission allocation, while in the United States this figure is closer to 90 percent. When analysts assign the majority of a dual-purpose farm’s emissions to milk alone, the milk looks dramatically worse than it should.

This realization pushed the researchers toward an alternative metric: the carbon footprint per unit of nutrient production, such as the protein or calories for human consumption generated by the farm. Because this functional unit accounts for the nutrients provided by both meat and dairy, it places the Bangladeshi farm on much more similar ground to U.S. producers, allowing a fair comparison where one was previously distorted. If we use that traditional allocation method of emission, it overestimates emissions, Uddin says. But if we use the specific allocation method that is applicable for production system in Bangladesh, it really gives you a different answer. The choice of accounting method, in other words, is not a technical footnote but a decisive factor in how a nation’s dairy sector is judged.

The implications extend well beyond a single university farm. Carbon footprints vary significantly between farms even within the same region, which means regional averages can obscure both problem operations and model ones. By looking closely at individual farms, as this study did, researchers can gain more informed insight and provide better recommendations for others. We can see which farms are doing better compared to others, Uddin says, and the farm that has a low footprint, the practices they’re doing, can those be translated into key messages that can be used by other farmers to make changes? Accurate measurement also carries growing economic weight, since environmental performance is becoming a factor in international commerce. Let’s say two different countries are exporting the same product at a similar price, Uddin notes. If one is more environmentally friendly than the other, importers are going to prefer the one that is environmentally friendly. For developing dairy nations, the study’s message is twofold: better data yields fairer numbers, and raising productivity may do more for the climate than any single emissions technology.

Subject of Research: Carbon footprint measurement of milk in dual-purpose dairy production systems in Bangladesh

Article Title: Measuring milk’s carbon footprint

Article References: Measuring milk’s carbon footprint. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: carbon footprint, dairy farming, Bangladesh, life cycle assessment, enteric fermentation, IPCC Tier 2 equations, emission allocation, dual-purpose cattle, milk productivity, Journal of Dairy Science, greenhouse gas emissions, sustainable agriculture