The link between methane gas and climate change has been widely published, with most of the scientific world agreeing that, in terms of climate warming abilities, methane is far more efficient at storing heat than CO2.
The World Economic Forum said that methane is the second-largest contributor to climate change, with the majority of methane emissions caused by human activity coming from livestock, mainly cattle burps and flatulence.
A 2015 study suggested that using seaweed as an additive to cattle’s normal feed could reduce methane production, but this research was done in a lab without live animals.
Ermias Kebreab, associate dean and professor of animal science at the University of California, and Breanna Roque, a PhD student in animal biology, also at the University of California, studied sustainable agriculture with a key focus on livestock.
The pair recently published a study in which they showed that using red seaweed as a cattle feed supplement can significantly reduce both methane emissions and feed costs without affecting the quality of the meat.
The study suggested that if these findings were scaled up and commercialised, it would transform cattle production into a more economically and environmentally sustainable industry.
The study explains that ruminant animals, such as cows, sheep, and goats, can digest plant material that is indigestible for humans and animals with simple stomachs, such as pigs and chickens.
This unique ability stems from ruminants’ four-compartment stomachs – particularly the rumen compartment, which contains a host of different microbes that ferment feed and break it down into nutrients.
This process also generates by-products that the cow’s body does not take up, such as carbon dioxide and hydrogen. Methane-producing microbes, called methanogens, use these compounds to form methane, which the cow’s body expels.
Initially, the study that analysed the problem in 2019, which was the first such research that was conducted in cattle rather than in a laboratory. The researchers showed that supplementing dairy cows’ feed with about 10 ounces (283g) of seaweed a day reduced methane emissions by up to 67%.
However, the cattle that ate this relatively large quantity of seaweed consumed less feed. This reduced their milk production, a clear drawback for dairy farmers. Researchers went back to the drawing board.
For the recent study, researchers added 1.5 to 3 ounces (42g-80g) of seaweed per animal per day to 21 beef cows’ food for 21 weeks. It took some time for the animals to get used to the taste of seaweed, but they became accustomed to it within a few weeks.
It was found that the cows released more hydrogen, up to 750% more, as their systems produced less methane. Hydrogen has minimal impact on the environment, while seaweed supplements does not affect the animals’ carbon dioxide emissions.
A key finding of the study was that the steers converted the seaweed feed to body weight up to 20% more efficiently than cattle on a conventional diet. This benefit could reduce production costs for farmers since they would need to buy less feed.
The authors admitted that they still do not know for certain why supplementing cattle feed with seaweed helped them convert more of their diet to weight gain, but said that previous research suggested that some rumen micro-organisms can use hydrogen that is no longer going into methane production to generate energy-dense nutrients that the cow can then use for added growth.
When a panel of consumers sampled meat from cattle raised in the study, they did not detect any difference in tenderness, juiciness, or flavour between meat from cattle that consumed seaweed and others that did not.
Commercialising seaweed as a cattle feed additive would involve many steps. First, scientists would need to develop aquaculture techniques for producing seaweed on a large scale, either in the ocean or in tanks on land.
“Farmers and ranchers could also earn money for reducing their cattle’s emissions. Climate scientists would have to provide guidance on quantifying, monitoring and verifying methane emission reductions from cattle. Such rules could allow cattle farmers to earn credits from carbon offset programs around the world,” the authors concluded.
South Africa boasts over 3000km of coastline. The country is one of the best places to take advantage of the many benefits which seaweed has to offer.
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