Antimicrobial Therapy in Swine

Antimicrobial use in swine has always been substantial and in some cases, the swine industry has been considered overreliant on their use. This chapter provides insights into the use of antimicrobials in swine and to help with decision making regarding when to use antimicrobials, selection of active substance, route of administration, and dose. The concept of primary and secondary infections must be taken into consideration when selecting antimicrobials for treating mixed infections. Antimicrobial resistance in porcine bacterial pathogens poses treatment problems in some situations, including the occurrence of multiresistant bacteria. The antimicrobial susceptibility patterns are different between farms, pigs, and countries. In the optimum situation, assessment of antimicrobial susceptibility should be performed regularly for those diseases that are treated on the individual farm. For individual treatments, three days are normally sufficient while batch medications should have a duration of 4–5 days, although for E. coli postweaning diarrhea this may only be three days.