Keep the exterior of units clean during milking. Andy Johnson, a veterinarian from Clintonville, Wis., who specializes in milk quality, suggests using a drop hose with detergent or sanitizer attached.

At a minimum, the units should be sprayed down after each pen of cows. Preferably, they should be sprayed down after each side of the parlor is done. This will help reduce the risk of new infections, specifically environmental pathogens and mycoplasma.