Feed Additives: Reducing Methane Without Compromising Milk Quality
In the recently concluded ClimateMilk project, The Department of Food Science at Aarhus University reveals that innovative methane-reducing cow feeds not only cut emissions but also enhances the nutritional profile of milk without compromising its quality.
The quest for a sustainable future has reached the barn door, and exciting news is emerging from dairy farms and labs worldwide. The ClimateMilk project, led by Associate Professor at The Department of Food Science Nina Aagaard Poulsen at Aarhus University, shows that feed additives designed to reduce methane emissions do not have any strong negative effects on milk composition in the project and can in some cases even enhance milk quality.
A game-changer for milk production
Feed additives, such as nitrate or synthetic compounds like Bovaer (3-nitrooxypropanol), can be used to cut down on methane emissions from dairy cattle. In the ClimateMilk project the individual effects and possible synergies of three methanereducing feeding strategies on milk and dairy product quality were investigated: addition of Bovaer (3-NOP), nitrate and supplementation of whole-cracked rapeseed to dairy cows’ diet.
The team’s findings showed that cows supplemented with whole-cracked rapeseed, nitrate and methane-reducing additives such as Bovaer (3-NOP) in some cases produced milk with higher levels of beneficial fatty acids, and a richer vitamin profile, whereas minor effects were found on mineral and protein compositions.
The study found that adding whole-cracked rapeseed to cows' diets (at 63 grams of crude fat per kilogram of dry matter) improved the nutritional quality of milk by increasing the proportion of healthy unsaturated fatty acids and reducing the proportion of less healthy saturated fats. Additionally, whole-cracked rapeseed boosted vitamin E levels in milk, further enhancing its nutritional value. Adding Bovaer (3-NOP) at 80 milligrams per kilogram feed dry matter increased vitamin B12 levels in milk by 21%, while nitrate supplementation at 10 grams per kilogram feed dry matter raised vitamin B2 levels by 5% in milk.
The study also confirmed previous findings of using Bovear (3-NOP) resulted in higher proportions of short-chain fatty acids in milk.
“So the primary objective of the project was to look into the milk quality and functionality in relation to these different feed additives,” Associate Professor Nina Aagard Poulsen says. “There was an interest in seeing if there’s any effect on the milk composition itself, which either affected the nutritional value of the milk or the further use of milk in dairy products,” she says and adds that:
“We have done one of the most comprehensive studies of possible effects on milk composition related to these three specific strategies to generate a lot of detailed knowledge on possible changes in milk quality.”
In one animal feeding trial, where cows were fed Bovaer (3-NOP) at 60 mg per kilogram dry matter, butter results from a sensory study at the Arla Innovation Centre and additional butter analyses showed no noticeable differences in look, taste, texture, or how it spreads compared to regular butter. Additionally, this butter stayed fresh longer, spoiling more slowly at both room temperature and in the fridge.
Postdoc at The Department of Food Science and researcher on the project Gayani M.S. Lokuge explains: “We observed changes mainly in the fatty acid composition, so we focused on the fat-related properties of the milk, which led us to study the butter properties.”
How it works
In the intricate world of a cow’s stomach, a bustling community of microbes work tirelessly within the rumen (a part of their stomach) to digest fibrous plant material. Among these microbes, some have a unique side effect: they produce methane as a biproduct of digestion. By changing the feed or introducing feed additives, it is possible to significantly reduce the production of methane in the rumen, making the process more sustainably oriented.
“These possible changes can affect the milk the cow produces because action of the microorganisms in the rumen are related to important parts of the milk like fatty acids and B vitamins,” Associate Professor Nina Aagaard Poulsen explains.
"Finding ways to reduce methane emissions is important for making dairy farming more sustainably oriented. For farmers and dairy producers, it's good news that adoption of these strategies don't have negative effects on the milk composition," Nina Aagaard Poulsen asserts.
Addressing concerns
Introducing new feed additives or changing the feed through fat supplementation may lead to concerns: Are these additives safe? Will they affect the taste or shelf life of milk?
Bovaer (3-NOP) was officially approved by the European Food Safety Authority (EFSA) and EU-authorized in April 2022. According to the EFSA, extensive testing has been done to ensure there are no negative impacts on milk safety, confirming that it’s safe for the animal and consumer.
Associate Professor Nina Aagaard Poulsen shares: “Our focus was on possible changes in milk composition, but we also measured possible transfer of nitrate to the milk, when the nitrate was added to the feed. We could clearly see that while nitrate levels were increased in the milk, it was well below the limit for nitrate in water.”
“Drinking a glass of milk is valuable much of our daily intake of B vitamins comes from milk and dairy. We were concerned that adding these feed additives might affect the B vitamins in milk, but we observed the opposite. The B vitamins increased," Nina Aagaard Poulsen highlights.
What’s next?
Starting January 2025, all conventional dairy farms in Denmark with more than 50 cows are required to reduce methane emissions by adjusting their feed. This can be achieved by either increasing the fat content in the cows’ diet or adding Bovaer (3-NOP).
As more farmers and producers embrace these feed innovations, the potential benefits grow. Researchers are now exploring how to optimize feed and feed additives for different herds and diets, ensuring every farm can find a solution that fits their needs.
At The Department of Food Science at Aarhus University, Nina Aagaard Poulsen is already looking at the next important steps:
“What’s next is that we plan to conduct more tests to further confirm some of the effects we’ve seen in this project. We already have new projects starting up that will dive into the action of fat and nitrate,” she confirms. “It’s all about following the implementation and confirming our results – and maybe also getting a better understanding of exactly why we see these changes.”
_________________________________________________________________________________
The ClimateMilk project, which began in 2020, was a collaborative effort involving the
Department of Food Science and the Department of Animal and Veterinary Sciences at Aarhus University, the Arla Innovation Centre, and DSM. It concluded with a PhD thesis submission by Gayani M.S. Lokuge in late 2023. Milk samples were collected from three distinct animal feeding trials, providing valuable insights into the future of sustainable dairy production.
SCIENTIFIC DECLARATION & CONTACT INFORMATION
SUBJECT | CONTENT & PURPOSE |
Study type | The presented results are based on milk samples collected from 3 animal feeding trials conducted at The Danish Cattle Research Centre, Aarhus University. |
External partners | Department of Food Science, Aarhus University. Department of Animal and Veterinary Sciences, Aarhus University. Arla Foods Innovation Centre. DSM. |
External funding | Mejeribrugets Forskningsfond and Arla Foods. |
Potential conflicts of interest | This project was supported by and made possible through collaborations with Arla and DSM. |
Link to scientific papers | |
Contact information | Nina Aagaard Poulsen Associate Professor at Department of Food Science at Aarhus University E-mail: nina.poulsen@food.au.dk Tel: +45 23 96 70 03 Gayani M.S. Lokuge Postdoc at Department of Food Science at Aarhus University E-mail: gmadu@food.au.dk Tel: +45 91 98 99 68 Kimie Kongsøre Journalist and Science Communicator Department of Food Science at Aarhus University E-mail: kiko@food.au.dk Tel: +45 20 84 43 63 |