Methane produced by livestock waste is a serious greenhouse gas--much stronger than CO2--that makes a big contribution to global warming.
Cattle-rearing alone creates more greenhouse gas than cars!But methane is great fuel. Hm [scratches head]. What to do?
Apparently, it's
really easy to capture
biogas & put it to immediate use on very small scales--you don't need massive plants & storage facilities...
just a rubber inner tube.

And while you're at it,
why stop with animals? I once suggested this self-supplied fuel source to an arctic explorer, but he didn't seem too enthused.