Liam Sinclair, Professor of Animal Science, says: "Methane is produced in the first stomach of the cow which we call the rumen. In there we find billions of microorganisms that ferment the food that goes in. As a consequence, the cow produces methane which she burps out. This is part of the natural digestive process and it's something that cows have evolved over hundreds of thousands of years."
Greenhouse gas emissions from dairy farms represent only 2% of the UK's total emissions.
Visit our environment section to find out more.