A small supplement of algae in cattle feed could reduce their methane emissions by more than 80%, according to an experiment conducted by researchers at the University of California at Davis.
Our greenhouse gas (GHG) emissions are the main cause of the acceleration of climate change. We know that breeding is responsible forabout 14.5% of these emissions and half of these come from cows and other ruminants which release methane throughout the day as they digest forages.
In order to fight against global warming, many studies advise to drastically reduce our meat consumption. Conducting the most comprehensive survey to date on the environmental impact of food production, researchers have recently found that buying meat or dairy even from sustainable sources did not outweigh the benefits of a vegan diet.
However, some researchers believe that we could fight differently by focusing on the livestock nutrition. This is the case of Ermias Kebreab of the University of California at Davis.
In 2018, Kebreab and his team had already distinguished themselves by reducing methane emissions from dairy cows by more than 50%. To do this, they supplemented their diet with seaweed for two weeks. These algae, of the species Asparagopsis taxiformis, in fact inhibit an enzyme in the digestive system of cattle which contributes to the production of methane.
In a new study published in the journal PLOS ONE, the researchers tested the effectiveness of this longer-term approach on beef raised for their meat. Over the past year, they have added small amounts of algae (about 80 g) to the diet of 21 cattle every day for five months. They then tracked their weight gain and measured their methane emissions four times a day.
Less GHGs for the same taste
Result: the cattle gained as much weight as their companions on a usual diet, while emitting 82% less methane into the atmosphere. A panel of taste tests further revealed no difference in the flavor of the meat of the animals fed the algae compared to that developed by the control group. Similar tests on dairy cattle had already shown that the algae also had no impact on the taste of the milk.
“We now have strong evidence that algae in cattle diets are effective in reducing greenhouse gases and that their effectiveness does not decrease over time.“Said Ermias Kebreab. “This could help farmers to producing beef and dairy products more sustainably“.
This is obviously just the start. Researchers are now studying ways to cultivate this species of algae. There is indeed not enough in nature for wide application. Another challenge arises: How could ranchers provide algae supplements to free-range grazing cattle? This will be the subject of Kebreab’s next study.