A cow's genome has been sequenced for the first time which could pave the way to a livestock revolution, say scientists.

Experts believe understanding the genetic blueprint of domestic cows will have a major impact on livestock breeding and will help farmers boost milk production and create healthier herds.

The cow genome also has important implications for human health because cattle and humans have about 80 per cent of their genes in common.

The multimillion-pound project took more than 300 scientists from 25 countries six years to complete.

The team unraveled 22,000 genes that make up the genetic code of a Hereford cow living on a research farm in Montana, U.S.

The cow's DNA was then compared with cattle from six other breeds. This was used to analyse variations of almost 500 cows from 19 different regions.

As in humans, the chromosomes of cows - packages of DNA that include the genes - were found to contain large duplicated regions.

In humans, these 'segmental duplications' are associated with a range of problems including neurological disorders and birth defects.

But in cows they were often beneficial, affecting genes related to immunity, metabolism, digestion, reproduction and milk production.

Some of the chromosomal rearrangements are thought to explain the cow's unique ability to convert grass and other low-energy food sources into high-octane muscle, fat and milk.

'Diversity'
Dr Shirley Ellis from the Institute for Animal Health in Newbury, Berkshire, said: 'This important achievement provides a sound basis upon which to base future studies into the genetic diversity present in different cattle breeds and populations.

'It is crucial that we preserve this variation through appropriate breeding programmes in order to maintain healthy cattle populations both in the UK and worldwide that are best able to cope with climate change and emerging diseases.'

Cows join the exclusive club of animals who have had their genome sequences including humans, rodents and other primates.

Professor Douglas Kell, chief executive of the Biotechnology and Biological Sciences Research Council, which funded many of the UK scientists, said: 'There is a looming crisis in food production on the horizon.

'The inexorable growth in the global population and changing consumption patterns in the developing world mean that even before you include climate change we have to find ways to produce more food with fewer resources.

'We need to recognise that livestock play a key role in many people's diets. Research such as the cattle genome project underpins the delivery of sustainable and nutritious meat with the highest possible standards of animal welfare.'

Genome sequencing of other livestock including sheep, pigs and goats is expected to follow.