Cattle may be bred to grow faster and eat less - and could cut methane emissions by a third

Farmers could start breeding cattle next year which grow faster but eat less feed so they cut the livestock industry's carbon footprint.

Methane emissions from cattle may be cut by about a third if farmers used the most environmentally-friendly animal breeds, scientists say.

The difference in emissions from the best and worst cattle was about 30%, according to Professor Mike Coffey from Scotland's Rural College.

He said by 2020, farmers will able to select bulls for breeding that will father dairy cows that eat less feed for the amount of milk they produce.

But Prof Coffey said the next stage will be trying to measure the methane given off by different breeds of cattle to find which are the lowest emitters.

Methane, produced when a cow burps or passes wind, is a potent greenhouse gas and is about 28 times more powerful than carbon dioxide at warming the Earth.

He said: "There's a huge prize available, the difference between the best and worst animals in cattle feed efficiency is about 30%.

"So if every farmer in the country used the best animals we could save about 30% of emissions in cattle."

He added: "By next year farmers will be able to select bulls whose daughters consume less feed for the amount of milk they produce.

"Where we go next is can we actually measure methane emissions from groups of animals."

Prof Coffey said shoppers could soon be able to check meat labels to find out how much environmental impact their food has had.

He added: "My expectation is that at some point in the near future there will be product labels that relates to the efficiency or carbon impact of the food."

Meanwhile, scientists have warned that everyone going vegan would not solve the environmental problems in the farming sector.

Professor Geoff Simm, from the University of Edinburgh, said that the meat sector was being "demonised" and that going vegan would not minimise land use.