Fluids are important to maintain healthy cell function and circulation. Cows with acute mastitis need to be encouraged to drink with TLC or intravenous hypertonic saline. Thus treatment strategy must be aimed at the critical links. Physical blockage of udder tissue is a significant barrier to drug action. Chronic mastitis is an udder tissue disease, not a milk disease.
Most organisms attach to the cell linings, and have varying abilities to cause deeper tissue damage.
High tissue levels of antibiotics are necessary to get at these organisms. This can only be done by systemic antibiotics, administered intramuscularly or intravenously. The udder has an excellent blood supply. NMC 1994 lists reasons why antibiotic therapy of clinical mastitis may fail. Drug cannot reach all infection sites.