Cows' farting and burping must be brought under control because they're causing global warming problems, a climate change expert has warned.
Just one cow gives off enough harmful methane gas in a single day to fill around 400 litre bottles, which is really bad for the environment.
The gas goes up into the atmosphere and makes the hole in the ozone layer bigger, worsening global warming.
Dr Chris Jardine says the government must do more to halt the gassy problem.
And it's not just cows - sheep and goats also produce methane, which is 20 times more harmful to the environment than carbon dioxide.
Dr Jardine, from Oxford University, said that the government needs to give more help to farmers.
Cutting the gas would also be good news for farmers, because it's thought if the animals aren't burping and farting then they would be able to grow more quickly.
But the government says its plans include ways to help farmers protect the environment.