FLORFENICOL IN ATLANTIC SALMON, SALMO-SALAR L - FIELD-EVALUATION OF EFFICACY AGAINST FURUNULOSIS IN NORWAY

The efficacy of florfenicol in the control of natural outbreaks of fur unculosis in Atlantic salmon, Salmo salar L. was evaluated on five Nor wegian farms during the summer of 1992. A total of 115 245 first- or s econd-generation fish received florfenicol with feed at a dose rate of 10 mg kg-1 body weight daily for 10 consecutive days. Comparisons wer e made with similar pens of fish medicated with the preferred treatmen t for each location. In the 10 days following introduction of therapy, all treatments were associated with a rapid decline in mortality caus ed by infection with Aeromonas salmonicida. Florfenicol-medicated salm on had a lower specific mortality than those given oxolinic acid, flum equine or a trimethoprim and sulphadiazine combination. No adverse rea ctions to treatment with florfenicol were observed.