Breeding cows that belch less could help save the environment, researchers have claimed.
An international team of scientists is exploring how to produce cattle that emit less methane into the atmosphere.
The University of Aberdeen is leading the £6.5m RuminOmics project to increase the efficiency of ruminant farming while lessening its negative environmental impact.
Methane forms in the gut of ruminants such as cows and is mainly released into the atmosphere when the animals belch.
The greenhouse gas is said to have a global warming potential 25 times that of carbon dioxide.
Initial research supports the idea that the genetics of an animal influence the level of methane it produces, scientists said.
Professor John Wallace, of the university's Rowett Institute of Nutrition and Health, is leading the study.
He said: "Methane production is important for cattle and sheep farmers because if the amount of methane produced can be lowered then there are benefits for the environment, production and profitability."
The team has studied a group of 25 dairy cattle to identify animals that produce less methane across a range of diets.
"Our work suggests there is considerable variability between individuals, with some producing more than others," Prof Wallace said.
"The finding has led the team to ask whether animals which are low emitters always emit low levels under all circumstances."
The EU-funded study will eventually include 1,400 animals and scientists hope the results will help the livestock industry choose cattle that will have less of a negative impact on the environment.