Scientists are working to beat global warming by stopping cows from burping and farting so much.
Cows can produce 500 litres of methane, which is bad for the environment, every day, mostly through burping.
Experts in Aberdeen hope an additive in their feed will prevent cows and sheep from making so much of the gas.
It could also be good news for farmers, because it's thought putting out less methane saves energy for the animals, letting them grow more quickly.
In tests on sheep, scientists found that for every kilogramme of the special food an animal ate, it got 10% more body weight.
The additive in the food works as part of the normal way the cows break down food.
It's hoped the special feed could cut the amount of methane cows produce down by 70%.