I have been wondering how that figure of 10% (see an earlier post on cow’s farts) was arrived at. There is a simple device, occasionally used by doctors (or more likely some poor bloody nurse), called a ‘Flatus Tube’. This is shoved up a patient’s arse to release trapped gases when their volume and pressure reach dangerous levels. There is also a device called a Spirometer, normally used to measure exhalations at the patient’s other end. I suppose a researcher armed with these must have spent a full 24 hours with a cow, inserting the tube every now and again and noting down volumes. (Judging from the photograph I posted the other day, cows don’t much mind what happens at that end.) One would then have a figure for the daily volume of farts produced by one cow, which one would multiply by the number of cows in the world. Perhaps measurements would have to be taken in various environments; perhaps Indian cows fart more (or I would guess less) than American ones.