Abstract: | Three experiments were done to evaluate some antibiotic therapies that are used commonly to treat pigs infected with Haemophilus pleuropneumoniae. Haemophilus-free piglets, 12 weeks of age, were challenged in a chamber with an aerosol of H. pleuropneumoniae serotype 1 and were medicated with antibiotics at various times before or after challenge. Antibiotic formulations which are commonly used to treat pneumonia in swine were used. They were chloramphenicol, penicillin, and a long-acting formulation of oxytetracycline given intramuscularly; and oxytetracycline, chloramphenicol and spiromycin (investigated as a potentially useful antibiotic) given in solution as the sole source of drinking water. Infection, disease (death, fever, gross lung lesions) and growth rate were measured in pigs following experimental challenge. |