Eefficacy of Different Preparations of Florfenicol on Experimental Colibacillosis in Chicken

To investigate the therapeutic effects of florfenicol,different dosage forms of florfenicol were prepared and used in experimental colibacillosis in chicken.Florfenicol premix was added to the feed at 100mg/kg 24h before injection of E coli suspension,and the soluble florfenicol powder was administered via drinking water at 100mg/L just after the challenge infection.These two preparations were applied for five successive days.Florfenicol injection was administered intramuscularly at a single dose of 20mg/kg 4h after injection of E.coli suspension.The protected animals of different groups were countered for evaluation of efficacy.The results showed that the effective rates of florfenicol premix,soluble florfenicol powder and florfenicol injection for colibacillosis in chicken were 70%,90% and 93.3% respectively,while the mortality of the control group was 73.3%.The weight gains were not significantly different among groups.The results above suggested that the soluble florfenicol powder and florfenicol injection might be superior to florfenicol premix in controlling the severe infection with E coli in chicken.