In this project, the effect of red algae on methane production and on the feed digestibility for Swedish dairy cows is tested.
The environmental impact of dairy cows is largely due to methane emissions from their digestion. The cows that are ruminants have a unique ability to convert fiber-rich feed into milk and meat. This is possible thanks to all the microbes found in the cow's largest stomach, the rumen. However, it is just this process where the feed is fermented that leads to methane being produced as the final product. The methane-forming microbes, called methanogens, are the ones responsible for the entire methane formation. In recent decades, a great effort has been invested in finding strategies to reduce the methane emissions of cattle and the livestock sector has been identified as a key player in reducing greenhouse gas emissions.
Several new studies in the laboratory environment (in vitro) have shown that the addition of the macroalgae Asparagopsis taxiformis in feed to ruminants has resulted in a significant reduction in methane production, some of the studies have shown a reduction of as much as 99%. Last year, a study from the US was published in which dairy cows were fed the algae Asparagopsis aramata for 3 weeks. Results from this study showed that algae reduced methane production per kilo of feed by up to 42%. It is primarily the active substance bromoform in the red algae Asparogopsis that blocks the methane formation of the methane-producing methanogens.
Since A. taxiformis has shown very positive results on methane reduction in vitro, it is very interesting to investigate what effect this algae has when given to milk-producing cows fed a typical Nordic diet. Therefore, in this study we will measure the effects of algae A. taxiformis when given to dairy cows for 2 months, partly how it affects the methane production of the cows and partly how it affects the digestibility of the feed of the cows. At the same time we want to find out if, and if so in what form, bromoform ends up in milk, urine or faeces.
Our study is structured in a series of well-controlled experiments, and is based on the latest techniques in the field. Together, our approaches provide new insights into the overall impact of opportunities to use A. taxiformis to reduce methane production in dairy cows.