Veterinary: Eating stones off ditches

Every now and then, I’m shown a cow ‘licking the ditches and drinking water from pools on the passageway’. Other than that, the cow might appear normal.

My suspicion is aroused, and, following an examination of all the systems, I would take blood samples for mineral analysis.

There is not much point in taking blood samples from just this one cow. That will only give a limited opinion, so we would drive in other companions, perhaps nine, and bleed them, too.