and rainer roehe s work shows that genetics can predict which animals will have the right microbe cocktail to produce the least methane. in other words, you can breathed low methane producing cattle. you can select, you can say that cow, that bull, they have good stomach stuff. you can put them together and make another cow with the same stomach stuff. yes. reporter: how much less? we are predicting we will reduce emissions by 50%. reporter: 50%. yes. reporter: how do they know? they measure it? they put cows in hermetically sealed chambers for three days and analyze the gasses they belch out. and there s another benefit: producing methais actally a waste of energy for a cow. the less they produce, the more efficient they are at turning cattle feed into human food win-win. still, a 50% reduction in