After evaluating possible benefits and risks, determining whether or not to use antibiotics for treatment depends on the diagnosis, including the bacterium involved and the specific drug and its dosage schedule. Which drug to select also hinges on the course of the infection, and the chemistry or pharmacology of the drug in the live animal. It is important to realize that most animals recover from disease with no treatment. This is due to their own defense mechanism. Therefore, antibiotic treatment is not the only, or necessarily the best, defense.
Treatment frequently aids in providing time for the immune response to reach protective levels.
Additional information concerning past history of the herd and environmental factors provide a basis for medical decision making. Similarly, laboratory work is necessary at some point in the course of many problems if you are to expect effectiveness of treatment procedures. Confusion seems to exist about antibiotic susceptibility tests. There is an apparent lack of understanding about both their interpretation and the role such testing plays in a treatment program. In the laboratory, isolated bacteria are exposed to a variety of antibiotics.