Ders gold in tham hills and ders fuel in that cows behind.
New science is hinting that a little seaweed fixes it all:
https://modernfarmer.com/2016/10/seaweed-livestock-methane-emissions/
"the researchers found, reduced methane emissions in cows by more than 99 percent, at fairly low doses"
Methane can be captured true enough, but that would only work for 100% indoor cows and it would be an expensive system of fans seperators pumps holding containers to process all those gases. Liquids are easier to work with obviously. Of course when you pour money into high birth-rate slash-n-burn societies then all those hard-fought improvements to improve world air quality go away with the next gust across the water.