Through their digestion, cattle release abundant methane – a powerful greenhouse gas. An experiment now shows that even a simple, natural addition to the cattle feed could reduce emissions: If red algae are mixed into the feed for beef cattle, their methane emissions are reduced by up to 80 percent, depending on the amount of algae. However, the research team found that the weight gain of the beef cattle and the quality of the meat are not affected.
With its almost 30 times higher greenhouse effect compared to carbon dioxide, methane is a particularly important factor in the context of climate change. Two thirds of man-made methane comes from agriculture, because cattle in particular constantly emit the gas when they digest grass and hay. From a climate protection perspective, it would therefore be advisable if we would eat less beef and dairy products – then fewer cattle would have to be kept.
Red algae as a feed additive
But what happens if not only people adjust their diet, but the diet of cattle is also changed? Researchers working with Breanna Roque from the University of California at Davis got to the bottom of this question. “Since a large part of the methane emissions from livestock farming comes from the animals themselves, nutrition plays a major role in the search for solutions,” says Roque’s colleague Ermias Kebreab. In an earlier study, the team was able to reduce methane emissions from dairy cows by adding algae to the animal feed for two weeks. It has been shown that ingredients in seaweed inhibit an enzyme in the cows’ digestive system that contributes to methane production.
The scientists have now also tested this feed mixture on cattle raised for meat production. To do this, they mixed around 20 Angus Hereford oxen with either no, a small or a high proportion of the red alga Asparagopsis taxiformis in the feed for five months. The team followed the weight gain and methane emissions of the ruminants. After slaughter, the meat quality of the cattle was also assessed. The result: cattle that consumed red algae with their feed emitted an average of 50 percent less methane than the control group. A high proportion of algae of around 80 grams could even reduce methane production by up to 80 percent.
Weight and meat taste unchanged
It was also shown that the animals with the algae feed gained just as much weight as the control animals. And that despite the fact that they ingested about one to two kilograms less dry matter per day. “The daily dry matter intake decreased by eight percent in the low dose group and significantly by 14 percent in the high dose group, while neither the low nor the high treatment group showed significant effects on daily weight gain compared to the control group,” said the Researcher. And not only the weight gain of the ox did not differ from the control group, but also the quality of the meat after slaughter: According to the evaluations, the algae feed did not show any effects on the fat, protein or carbohydrate content or on the moisture or the taste and consistency of the meat.
The scientists were thus able to show that feed supplementation can also reduce methane emissions from beef cattle in the long term. “This could help farmers sustainably produce beef and dairy products that we need to feed the world,” says Roque. “But there is still more work to be done.” For example, it is still being investigated whether and how well red algae can be grown in large quantities in aquaculture, for example. Because the natural sources are not sufficient for a wide-ranging application. In addition, the transport routes should not be too long in order not to emit additional greenhouse gases. In addition, it is not clear how farmers can offer their cattle algae as a nutritional supplement when they are grazing.
Source: University of California Davis, Article: PLOS ONE, doi: 10.1371 / journal.pone.0247820