Somehow I don't think the cattle would understand the need for them to fart into glass jars OEJ !laugh!
However, expanding that a bit. Dairy farms could possibly collect the methane from the "slurry tanks" that all the cow poo is swept into from the milking sheds. A small(ish) processing plant connected to the slurry tank could collect the methane and store it in gas tanks ready for collection.
Myson.
Hey, that's gotta be worth an MBE at least !grin!
Arise Lord Myson of Bonkem !laugh!!laugh!