Genetics can determine how much methane cows release when burping and passing gas, researcher says

Cows are responsible for about 40% of global methane emissions.  Methane is the gas passed or belched by the world's 1.4 billion cattle. In Scotland, cattle can be found grazing on the lush green pastures.  

Some environmentalists believe that when it comes to global warming, meat, especially beef, is among the worst foods that can be eaten. 

According to scientists, the methane cows belch out while turning feed into food is a far more powerful greenhouse gas than even the carbon dioxide produced by burning fossil fuels.