Sean Tollenaar, dairy producer from Wheatland, Calif., wants to be sure that his milking crews use enough teat dip. So, he or a herdsman checks the teat dip barrels following each milking. He would like to see 19 gallons of teat dip used per day, which means the fluid level should decline by about 7 inches per day — or, 3.5 inches per milking since the farm is on a 2X milking schedule. Tollenaar uses a specially marked piece of PVC pipe to make the measurements.