A new international study led by McGill University in collaboration with Jefo Nutrition shows that supplementing dairy cow diets with microencapsulated B-vitamins can significantly reduce greenhouse gas emissions while increasing milk yield and quality. The use of the feed additive cut global warming potential, an internationally standardized measure of climate impact, by up to 18 per cent across seven countries.
The researchers calculated that its use in Canada alone would reduce carbon emissions by half a million tonnes. To arrive at that figure, they considered emissions not only from cows and their manure, but also from other components of dairy production. such as feed storage and transport.
"Livestock production contributes about 11 to 19 per cent of global emissions, and feed is one of the most accessible levers producers can adjust," said Ebenezer Miezah Kwofie, study co-author and Assistant Professor of Bioresource Engineering at McGill. "Our goal was to look at what can be done to minimize emissions with feed additives and determine how variation from one region to another changes the dynamic."
Working with cows' biology
Most vitamin supplements degrade in the rumen, the cow's second stomach, before they can be fully absorbed. The team used microencapsulated B-vitamins designed to bypass the rumen and release nutrients in the small intestine, where absorption is highest.
"Usually, non-protected vitamins are used after calving, when lactation puts a lot of stress on the animal," said Prince Agyemang, PhD student and study co-author. "This way, they get appropriately released."
This improved nutritional efficiency led to higher milk output and higher fat and protein content, key factors in how milk is priced. Because cows produced more milk per unit of feed consumed, the environmental impact per kilogram of milk decreased. This also reduced pressure on agricultural land and water resources needed to grow feed crops.
Study design and regional variation
The industry partner involved in this project conducted trials on commercial farms in North America, South America, Europe and Australia, with durations ranging from 120 to 213 days of lactation. Diets were standardized for ingredients and nutritional composition so researchers could isolate the effect of the additive.
Environmental impacts were assessed using ISO Standard 14044 and the International Dairy Federation's guide, which evaluates life-cycle emissions from the cradle to the farm gate. The researchers focused on global warming potential per kilogram of fat-protein corrected milk (FPCM), a standard measure that accounts for milk's energy content and allows fair comparison across regions.
Regional differences helped the team evaluate how variations in feed and climate influence the supplement's effectiveness. The additive's strongest effects were found in Latin America, with reductions as high as 18 per cent in Mexico and 10 per cent in Chile.
The environmental cost of producing and transporting the additive was minimal, contributing less than 0.02 per cent to the total carbon footprint per kilogram of FPCM.
Next steps
The team said they plan to model national-level adoption scenarios and explore combinations with other additives, including those that more aggressively target methane emissions. They also hope to develop tools to help farmers communicate emissions reductions to retailers and consumers.
About this study
"Global analysis of nutritional strategies to mitigate the environmental impacts of dairy production: the case of supplementing diets with microencapsulated B vitamins," by Prince Agyemang, Ebenezer M. Kwofie, Ludovic Lahaye, Melissa Otis, Emilie Fontaine, Victoria Asselstine, Aubin Payne and Greg Thoma, was published in Sustainable Production and Consumption in October 2025.
