Fact Check: Claims of Cow Deaths Linked to Bovaer Feed Additive in Denmark

Danish Dairy Industry Faces Crisis as Farmers Report Cattle Health Problems

Danish dairy farmers are raising alarm over a wave of serious health issues affecting their cattle, which some have linked to the feed additive Bovaer. Videos and testimonies circulating on social media show farmers describing collapsed cows, widespread diarrhea, reduced milk production, infertility, and even deaths allegedly connected to the methane-reducing supplement.

The claims have gained traction online, with some farmers reporting that discontinuing Bovaer use has resulted in healthier animals and improved milk yields. These concerns have grown serious enough to prompt official investigations by Danish authorities.

Bovaer, manufactured by Swiss-Dutch company DSM-Firmenich, is designed to reduce methane emissions from cattle by suppressing an enzyme in their digestive system. The product can cut emissions by up to 30% in dairy cows and potentially more in beef cattle – a significant benefit given that the agricultural sector is Europe’s largest methane emitter, accounting for about 56% of the EU’s methane emissions according to the European Environment Agency.

Despite the controversy, regulatory bodies have consistently vouched for Bovaer’s safety. The European Food Safety Authority published a scientific opinion in 2021 stating that Bovaer was effective and safe for dairy cows “at the maximum recommended level” and posed no concern for consumer safety or the environment. Similarly, the UK’s Food Standards Agency confirmed in December 2024 that cows metabolize Bovaer, preventing it from entering milk or meat products.

“It does not cause cancer and poses no safety concerns to consumers, animals or the environment,” the FSA stated, noting that “more than 58 studies on potential risks were evaluated and it was concluded that the additive is safe at twice the recommended dose.”

Independent experts have suggested that some safety concerns may stem from misinterpreting product labels. Jan Dijkstra, associate professor in ruminant nutrition at Wageningen University in the Netherlands, explained to Euronews that safety warnings on Bovaer’s label refer to handling precautions for factory staff working with the concentrated form, not the final product used in feed.

“Farmers don’t use pure Bovaer,” Dijkstra clarified. “Safety warnings are completely normal for an industrial additive in concentrated powder form.”

DSM-Firmenich maintains that Bovaer has been proven safe through more than 15 years of research with “no evidence of adverse health effects in cows.” A company spokesperson emphasized that approximately 400 Danish dairy farmers had used the additive successfully in the first nine months of the year “without ever being identified as a contributor to health issues in cows.”

The situation in Denmark has become particularly contentious since the country mandated the use of methane-reducing feed at the beginning of 2025 as part of its climate policy. Now, roughly 350 out of 1,600 Danish farmers have reported cattle illness and death, prompting investigations by the Danish Food and Veterinary Administration, SEGES Innovation, and Aarhus University.

DSM-Firmenich stated they are cooperating with investigators to determine whether Bovaer could be contributing to the reported health problems or if other factors like changes in diet composition might explain why only certain farms are experiencing issues.

Researchers at Aarhus University have noted that during their extensive research on the feed additive, they never observed the symptoms or deaths currently being reported. Other experts share similar observations, raising questions about the cause of the problems.

“Scientific studies indeed sometimes, but not always, show reduced feed intake and milk production; this effect seems to occur more frequently at higher doses of 3-NOP,” Dijkstra noted, referring to Bovaer’s active ingredient. “It is unclear at the moment if Bovaer is really causing the problem in Denmark. For example, at the same time of introducing Bovaer, half of the farmers reporting problems changed diet composition.”

Dijkstra emphasized the unusual nature of the Danish situation, pointing out that hundreds of farmers in the Netherlands, Belgium, and other European countries have used Bovaer for several years without reporting similar problems. “No problems have been reported by these farmers, so the Danish situation as to cow health at present is rather unique,” he said.

As investigations continue, the controversy highlights the complex balance between implementing climate-friendly agricultural practices and maintaining animal welfare standards.