“Bovaer® has been linked to reports of cattle sickness and diarrhea, as well as claims of reproductive issues or shortened lifespans.”
Bovaer® is safe for cows. Animal health and welfare have been studied alongside methane reduction throughout its development. Research has examined feed intake, milk yield, composition, fertility, and wider animal health, drawing on controlled studies, long-duration research, and commercial farm experience. Bovaer® is now fed daily to more than 500,000 cattle across more than 25 countries.
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Bovaer® | Sustainable Dairy and Low Methane Farming
“Does Bovaer® change the rumen microbes?” “Does Bovaer® stop working over time as the rumen adapts to it?”
Bovaer® has a specific and temporary mode of action. It targets a single enzyme used by specific rumen microbes during the final step of methane production. It does not kill microbes, disrupt digestion, or negatively affect the cow’s health or welfare. Once consumed, Bovaer® is rapidly broken down into compounds naturally present in feed. Its effect is reversible, meaning methane production returns to previous levels when supplementation stops.
Studies conducted over full lactation periods of more than 12 months show that Bovaer® maintains a consistent methane-reducing effect without affecting animal performance, health, or welfare. Research also shows that normal rumen function is maintained over time.
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“Some Danish farmers reported herd-health issues in 2025 and questioned whether there could be a link with Bovaer®.”
During autumn 2025, Denmark rapidly adopted Bovaer® across its dairy sector following mandatory methane-reduction requirements. Some farmers reported issues, and the Danish Veterinary and Food Administration commissioned Aarhus University to analyze the impact of Bovaer® in Danish dairy production.
Aarhus University analyzed 73 herds and approximately 27,650 cows. The analysis found no evidence of negative effects on milk yield, cow mortality, mastitis, or digestive and metabolic disorders linked to Bovaer®.
This does not mean individual farmers did not have real and difficult experiences that autumn; many did. The independent herd-level data analysis found that, in aggregate, no causal link to Bovaer® could be identified at herd level. At the same time, the underlying causes of the reported herd-health issues have not yet been fully established, and investigations remain ongoing.
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