COMMENT
Meat and dairy are New Zealand's biggest earners when it comes to exports, however, they are also our largest contributor to greenhouse gas emissions. As we try to balance our economy with our commitment to the Paris climate agreement new research out this week thinks the secret to reducing climate change could be through breeding less burpy cows.
Methane emissions from ruminants including sheep and cows account for about a third of New Zealand's greenhouse gas emissions and are by far the largest single contributor. Although methane stays in the atmosphere for less time than carbon, as a gas it is much more effective at trapping heat - acting as a blanket over our planet and playing a significant role when it comes to climate change.
Methane isn't physically produced by the ruminants themselves, instead, the animals act as a host to a group of microbes called methanogens that live in their digestive system. It is these methanogens that produce the methane by combining hydrogen and carbon dioxide during food digestion. To look at the relationship between methane emissions and livestock, a large European Union commissioned research project called RuminOmics took a team of more than 30 scientists and several breeds of common cow to see if there was a simple way to reduce the amount of methane produced.
The scientists inserted a brass cylinder into the mouth of the cows they were studying and pulled up fluid from the rumen, the first of four compartments found in the stomach of a cow. This is the area where grass that has been chewed and swallowed by the cow gets partially digested through a fermentation reaction. The researchers found that this fluid contained different types of protozoa, bacteria, fungi, DNA and single-celled organisms known as archaea. The bacteria produce hydrogen as they ferment the carbohydrates from the chewed up grass which is then combined with carbon dioxide by the archaea in the rumen producing a methane-rich gassy combination, 95 per cent of which is burped out by the cow.