Feeding seaweed to cattle could reduce the amount of methane they produce by up to 80 per cent without affecting the flavour or quality of their meat, study finds.
Methane is one of the most potent greenhouse gases, trapping 25 times more heat than carbon dioxide and every time a cow burps or passes wind a small amount of the gas is released into the atmosphere – globally this is a serious problem.
Combined, cattle are responsible for around half of the greenhouse gas emissions produced by livestock globally, the University of California, Davis team explained.
Now, a type of algae, known as Asparagopsis taxiformis, could be used to tackle this problem after supplements fed to cattle revealed it was able to curb the amount of methane cows’ produce by neutralising enzymes in their digestive system.
Researchers only tested the seaweed on bulls, not cows, so milk quality or taste hasn’t been tested, but a panel found meat was as tasty as those on classic diets.
Feeding seaweed to cattle could reduce the amount of methane they produce by up to 80 per cent without affecting the flavour or quality of their meat, study finds
ASPAROGOPSIS TAXIFORMIS: A TYPE OF METHANE REDUCING ALGAE
Asparagopsis taxiformis, also known as red sea plume or liimu kohu is a species of red algae found in tropical to warm waters.
It is a popular cuisine in Hawaii, used as a condiment and the name Limu kohu in the Hawaiian language means ‘pleasing seaweed’.
It is said to have a slightly bitter taste similar to iodine.
Studies have shown that when fed to cattle it can reduce the amount of methane they produce.
While this heightened methane production from cattle has prompted calls to stop the eating of meat, only a small portion of the earth’s surface is suitable for crops.
Study author professor, Ermias Kebreab, said: ‘We now have sound evidence that seaweed in cattle diet is effective at reducing greenhouse gases and that the efficacy does not diminish over time.
‘This could help farmers sustainably produce the beef and dairy products we need to feed the world.’
The researchers added ‘scant amounts’ of seaweed to the diet of 21 beef cows over the course of five months.
The Angus-Hereford beef bullocks were fed their usual diet of hay, grains, and corn, supplemented with either zero, low, or high concentrations of red seaweed.
The study authors measured the quantity of methane, hydrogen, and carbon dioxide released by individual bullocks periodically for 21 weeks and found that seaweed supplements reduced methane emissions by between 45 and 68 per cent.
The proportion of forage in the base diet also influenced emissions, they found.
The greatest reductions were found with a high seaweed-supplemented, low-forage diet, which reduced methane production by as much as 80 per cent.
To determine the level of emissions, cattle were fed a snack from an open air contraption, which measured the methane in their breath, four times per day.
Cattle that consumed doses of about three ounces of seaweed gained as much weight as their herd mates but produced 82 per cent less methane.
Professor Kebreab said: ‘Only a tiny fraction of the earth is fit for crop production.
Combined, cattle are responsible for around half of the greenhouse gas emissions produced by livestock globally, the University of California, Davis team explained
Researchers only tested the seaweed on bulls, not cows, so milk quality or taste hasn’t been tested, but a panel found meat was as tasty as those on classic diets
CATTLE STUDY: HOW BULLS ARE FED SEAWEED
Angus Hereford cross beef steer were randomly allocated to one of three treatment groups.
No seaweed, a small amount of seaweed and slightly higher concentrations in their feed.
They were all eight months old and came from the same ranch.
Each was fitted to a random individual pen, fitted with a feed bunk and fed twice per day at 0600 and 1800.
‘Much more land is suitable only for grazing, so livestock plays a vital role in feeding the 10 billion people who will soon inhabit the planet.
‘Since much of livestock’s methane emissions come from the animal itself, nutrition plays a big role in finding solutions.’
In 2018, the researchers were able to reduce methane emissions from dairy cows by over 50 per cent by adding seaweed to their diet for just two weeks.
The seaweed inhibits an enzyme in the cow’s digestive system which normally helps produce methane, the team revealed.
Scientists are already studying ways of farming the type of seaweed used by the researchers, as there is not enough of it in the wild.
Co-author Dr Breanna Roque said: ‘There is more work to be done, but we are very encouraged by these results.
‘We now have a clear answer to the question of whether seaweed supplements can sustainably reduce livestock methane emissions and its long term effectiveness.’
The findings were published in the journal PLOS ONE.
UK firm reveals plans for seaweed farms off the Welsh coast to grow eco-friendly cattle feed
A British firm is looking to help combat climate change by growing seaweed farms to remove carbon dioxide from the ocean while producing eco-friendly cattle feed.
Planting more trees is often touted a solution to help extract greenhouse gases from the air — as photosynthesis uses up carbon dioxide to create new biomass.
Yet trees grow slowly, the carbon they store is vulnerable to release by deforestation, and experts have said it may now be too late to put too much stock in this approach.
Kelp, in contrast, grows some 30 times faster — at up to two feet a day — and sheds a lot of its biomass out to the deep sea, where carbon can be permanently buried.
Carbon Kapture, an environmental start-up, says it plans to establish eight initial kelp farms in February, to harvest later this year, with 50 more to follow in October.
Sites being considered for the first farms are Carmarthen Bay and St Brides Bay in South Wales — along with areas in Cornwall, Devon, Yorkshire and around Scotland.
Kelp grown on the farms will be sold to farmers as animal feed — one which helps reduce the levels of problematic methane emissions from cattle.