Why do cows lick soil?

Cows lick soil because a shortage of mineral (possibly phosphorus or salt), rumen acidosis (this is controversial), craving for mineral (but not deficient), lack of long fiber, or boredom. Some cows consuming a wet ration with no long hay or lush pasture will eat soil. You might offer sodium bentonite, salt, and bicarb free choice (monitor intake) to see if this reduces soil licking. Be sure to consider the cost if luxury mineral consumption occurs! Pica or a depraved appetite, indicated by soil consumption, should be investigated by a more complete evaluation of the ration and animal health.

Mike Hutjens, Extension Dairy Specialist, University of Illinois – Illini DairyNET