Recognition of the fact that bovine mastitis is the most costly single cattle disease is disconcerting to the conscientious veterinarian. Farmers and veterinarians alike evidently need a more thorough understanding of mastitis to successfully prevent it, or to treat it when it exists. So much has been said about mastitis infusions in recent years that good herd management is sometimes neglected. One veterinarian very appropriately stated that, "The big fact remains that unless the farmer practices good management we don't get very far with treatment."