Feeding seaweed to cows can cut methane emissions, says Swedish report

Sweden moves step closer to making the use of methane-reducing cow feed additives such as seaweed a government policy

Sweden is one step closer to making the use of methane-reducing cow feed additives such as seaweed government policy after experts recommended further investigation into the area.

A report by the Swedish Environmental Protection Agency into reduced methane emissions says development in the field has been “rapid in recent years” and is among “a number of new interesting additives with higher potential”.

Among the cow feed additives cited in the report were the seaweed red algae and the chemical 3-nitrooxypropanol (3-NOP).

According to manufacturers, the daily feeding of red algae (where the active substance is bromoform) can reduce the methane emissions of meat animals by up to 90 per cent. But, the agency said, more knowledge on cultivation and use was needed.


3-NOP, which has been fed to several cattle categories in Sweden and elsewhere, has been approved for use in dairy cows in the EU since February 2022. The chemical can cut methane emissions by an average of about 30 per cent in dairy cows, according to the report, and by 45 per cent in meat cattle.

The discovery about the effects of feeding seaweed was originally made by researchers in Australia and works by preventing microorganisms in the cow’s first stomach from producing methane.

While some feed additives “appear to have significant potential”, it warns that there is still uncertainty over the long-term effects and factors preventing it from being used more within production systems.

“More research and analysis is required both in terms of today’s marketed products and to develop alternative, future feed additives,” says the report.

As a result of its findings, the study proposes that the government commission the agency, along with other authorities, to further investigate the area.

Lines of inquiry, it says, should include socioeconomic impact, support for farmers and other stages in the food chain, improved research, innovation initiatives and increased collaboration with the industry.

Other potential areas of investigation for “climate-smart cows”, it says, are enhancing productivity and genetic variations between breeds on how much methane they produce.

In 2021, Sweden’s agricultural sector produced 3.6m tonnes of CO2 equivalents of methane – 2.9m tonnes of which were produced by cattle digestion.

Emma Carlen, a climate analyst at the Swedish Environmental Protection Agency, said extra cost of measures to combat methane emissions was a big constraint for farmers, she said, which is why they wanted to look at what financial support might be needed, as well as other measures. – Guardian