New Zealand co-op Fonterra is extending the trial of Asparagopsis seaweed to test its effectiveness at reducing methane when used in every day farming environment. When trialled in laboratory conditions, the seaweed showed potential to reduce emissions by 80%, though this is expected by Fonterra to reduce in commercial applications.

The purpose of the extended trial is to explore the practicalities of using the seaweed supplement as part of normal farming operations, as it has to be practical for farmers to use and deliver results outside the laboratory. The trial will also test if the seaweed is safe for cows as well as consumers and make sure there is no negative impact on milk taste or quality from incorporating it as part of the cows’ diet. So far, small amounts have been fed to 900 dairy cows on a farm in Australia, with promising results at each stage.

The seaweed, which is common to waters around New Zealand and Tasmania in Australia, is being cultivated on a commercial scale by an Australian company, Sea Forest, which has ramped up production over the past year. If the on-farm trial proves successful, Fonterra farmers will have first access to the seaweed solution.

However, Fonterra has said that there is no single solution to the methane challenge and incorporating this type of seaweed into the cows’ diet is just one of a number of diet-based solutions that it is exploring. Fonterra has a stated ambition of being net zero by 2050.