Within a few hours of arrival, each calf was inoculated with a highly pathogenic and virulent E.coli strain possessing K99 adhesion (strain B4409 K30 H- K99+ F41) and susceptibility to Baytril®. As soon as symptoms of diarrhea were noted, calves were rehydrated before any other treatment, and the onset was designated Day 0 (D0).
Calves were randomly divided into two groups of 15 calves each. Group A received Baytril® Boli daily in a dose of 5 mg/kg b.w. for three days (D0 to D2). The calves in Group B received a placebo of Baytril® Boli with the same dosage regimen. No other treatments were administered. All surviving calves were sacrificed on D6 and gross-pathological examination on various organs and bacteriological examination was performed.
Treatment efficacy criteria were: mortality as percentage over the study period, survival time as delay between the day of death and the day of inoculation, clinical score (included feces consistency, degree of dehydration, and feed refusal).
Mortality was significantly lower in the Baytril® Boli group than in the placebo group. The isolation of the pathogen c E.coli on D6 (or on the day of death) showed that calves in the Baytril® group were bacteriologically cured.
Even under the conditions of colostrum-deprived calves inoculated with a highly pathogenic E.coli strain, and without supportive therapy (except rehydration until D2), Baytril® demonstrated its therapeutic efficacy.
In another study, the therapeutic efficacy of Baytril® 5% injectable solution was tested under field conditions.
31 beef calves under three weeks of age with diarrhea were included in the study.
E.coli and K-antigens were isolated from each calf before treatment. Rota virus was also found in all animals. Coccidia were also isolated from three calves; salmonella was found in one calf. From these results, diarrhea was assumed to be caused by E.coli and other pathogens.
The calves were divided into two treatment groups. Calves were treated with Baytril® by s.c. injection once daily for three consecutive days. Group A (19 animals) received 2.5 mg enrofloxacin/kg b.w.; Group B (16 animals) was treated with 5.0 mg/kg b.w.
Both dosage regimens showed good clinical efficacy. There was no difference in recovery status with or without other pathogens' involvement.