International scientists led by New Zealanders have identified the genetic makeup of over 500 species of bacteria found in the gut of cattle and sheep.
Previously the genomes of just 15 rumen microbial genomes were available to the scientific community.
The project was led by the former AgResearch scientist Bill Kelly and a current AgResearch scientist Sinead Leahy.
They were joined by nearly 60 scientists from 14 research organisations across nine countries.
Dr Leahy said the work was done by growing the bacteria outside the animal gut.
"Many of these bugs that we have worked with have never been brought to culture before," she said.
"We knew they existed but they have never actually been cultured or worked with in a lab.
"A component (of the research) was actually to culture the unculturable, and bring out these types of microbes that we knew existed but no-one had ever worked with before.
"It was the first step in getting down to the details of the microbes, who is there and what are they doing."
This research followed worries about methane emissions from belching livestock.
AgResearch said this was the largest source of methane connected with human activity, and emitted 125 million tonnes of methane into the air annually.
Dr Leahy said understanding the behaviour of micro organisms was essential to try to deal with this.
"We are doing a lot of work on technologies like vaccines and inhibitors," Dr Leahy said.
"But you don't want to upset the microbioal community in the ruminant, because both the cows and the microbes have a nice relationship.
"So with any technology that will interrupt that relationship, you will have to make sure the health and the productivity of the cow will not be affected."
De Leahy said the aim was to make sure that any modification of the miocrobial community inside a cow will have the best outcome.