Could seaweed eating cows be the answer to our problems on climate change?

Written by Gwynneth Borges, Graduate Student

With global warming steadily becoming a more pressing issue, a new-found discovery has come to light in that cows could help reduce greenhouse emissions through their diet. A cow can release around 70 to 120 kg of methane a year, and methane is considered to be a dangerous gas, which is 30-fold more harmful than carbon dioxide in its contribution to the greenhouse

How seaweed was noticed to be a mitigator of methane
A Canadian farmer began to notice that his cattle started looking healthier and producing ‘rip roaring heats’ with longer mating cycles, after they had eaten some washed up seaweed. This the led to a research study led by Rocky De Nys and a team of scientists at the James Cook University in Queensland, Australia. The scientists observed sheep that were fed a diet
containing 2 percent seaweed. When tested using a methane gas detector, these sheep recorded a fall in methane levels by 50-70 percent.

This research was then undertaken by Canadian researchers Rob Kinley and Alan Fredeen in 2014 who successfully proved the findings and expanded their study through a collaborative effort with Australia’s Commonwealth Scientific and Industrial Research Organization. The team tested the reaction of 20 species with bacteria found in the stomach of the cows. In some cows,
they found one such species of red algae which they believed had a significant effect on reducing the cows’ methane emissions. This species is known as Asparagopsis Taxiformis and, if present in just 2 percent of the diet, could reduce emissions of up to 99 percent of methane.

Casting a doubt on the study
While all this is very exciting, there have been some doubts surrounding it. Dr Andy Reisinger, the deputy director of the New Zealand Agricultural Greenhouse Gas Research Centre (NZAGRC), while looking into the research at James Cook University, weighed in on a potential problem. The main element in methane mitigation comes from chemical bromoform which is
produced in the cow’s stomach upon eating the seaweed. Bromoform while cutting the greenhouse emissions is also known to deplete the ozone layer. Since cows are now emitting bromoform, this could be another cause for worry in the environment.

The NIH database has also shown that there is evidence, however little, of bromoform increasing the risk to cancer in animals. This could affect the health of the livestock at the expense of the environment.

How Farmers remain hopeful
Still farmers remain hopeful; Irish farmers have welcomed the opportunity as it could help build on Ireland’s ‘sustainable grass-based model of food production’ as well as a way to use a natural resource to help fill out the cattle feeders at a potentially lower cost to the farmers’ bottom line. Thomas Cooney, the environment chairman of the Irish Farmers’ Association appealed to Irish scientists “to immediately investigate the potential for this research in an Irish agriculture context, and in the context of the opportunity that may exist for indigenous seaweed production”.

He added that, “We are an island nation with plenty of coastline and if we develop and improve our seaweed industry it could be a big bonus for our economy – more analysis into this exciting new research must take place as soon as possible”.

References: methane-emissions- climate-change-supercows-james- cook-university- a7849646.html 0487-z

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