Objective—To compare concentrations of
danofloxacin, enrofloxacin, and ciprofloxacin in plasma
and respiratory tissues of calves treated after challenge
with Mannheimia haemolytica.
Procedure—24 hours after challenge with
M haemolytica, 72 calves with clinical signs of respiratory
tract disease were randomly assigned to 1
of 12 equal treatment groups. Three nonchallenged,
nontreated calves formed a control group.
Challenged calves were treated with danofloxacin
(6 and 8 mg/kg, SC) and enrofloxacin (8 mg/kg, SC)
once. At 1, 2, 6, and 12 hours after treatment, 6
calves from each treatment group were euthanatized.
Antimicrobial drug concentrations were
assayed in various specimens. Peak plasma concentration
(Cmax)-to-minimum inhibitory concentration
(MIC; Cmax-to-MIC) ratios and the area under
the concentration versus time curve over a 12-hour
period-to-MIC ratios (AUC12h-to-MIC) were calculated.
Results—Danofloxacin and enrofloxacin had MICs of
0.03 µg/mL for the M haemolytica challenge isolate.
Danofloxacin administered at doses of 6 and 8 mg/kg
resulted in numerically higher geometric mean concentrations
of danofloxacin in plasma and all respiratory
tissues than geometric mean concentrations of
enrofloxacin after treatment with enrofloxacin.
Geometric mean concentrations of enrofloxacin were
numerically higher than geometric mean concentrations
of ciprofloxacin metabolite in plasma and almost
all respiratory tissues. Danofloxacin and enrofloxacin
achieved Cmax-to-MIC ratios > 10 and AUC12h-to-MIC
ratios > 125 hours.
Conclusions and Clinical Relevance— When used
to treat pneumonic pasteurellosis in calves,
danofloxacin and enrofloxacin can be expected to
deliver concentration-dependent bactericidal activity
against M haemolytica, the bacteria most commonly
associated with bovine respiratory tract disease.
(Am J Vet Res 2005;66:342–349)
Objective—To evaluate the efficacy and safety of administration of cefovecin, compared with cefadroxil, for treatment of naturally occurring secondary superficial pyoderma, abscesses, and infected wounds in dogs.
Procedures—Dogs with clinical signs of skin infection confirmed via bacteriologic culture were randomly allocated to receive a single SC injection of cefovecin (8 mg/kg [3.6 mg/lb]) followed by placebo administered PO twice daily for 14 days or cefadroxil (22 mg/kg [10 mg/lb]) administered PO twice daily for 14 days following a placebo injection. Two 14-day treatment courses were permitted. Treatment success was defined as reduction of clinical signs to mild or absent at the final assessment.
Results—Clinical efficacy achieved with cefovecin in dogs was equivalent to that observed with cefadroxil. At the final assessment, 14 days following the completion of treatment (on day 28 or 42), 92.4% (109/118) of the cefovecin group and 92.3% (108/117) of the cefadroxil group were treatment successes. There were no serious adverse events or deaths related to treatment.
Conclusions and Clinical Relevance—A single cefovecin injection (8 mg/kg) administered SC, which could be repeated once after 14 days, was safe and effective against naturally occurring skin infections in dogs and as effective as cefadroxil administered PO twice daily for 14 or 28 days.
Objective—To assess the serologic response of calves to inactivated and modified-live (ML) Mannheimia haemolytica (MH) preparations given alone and concurrently with combination viral vaccines containing ML bovine herpesvirus type 1 (BHV-1).
Animals—642 calves seronegative for BHV-1.
Procedures—In experiment 1, 192 calves received 1 of 3 MH preparations alone or concurrently received 1 of 3 MH preparations and 1 of 4 combination viral vaccines. In experiment 2, 450 calves received 1 of 4 MH preparations alone or concurrently received 1 of 4 MH preparations and 1 of 5 combination viral vaccines. Pretreatment and posttreatment blood samples were processed to obtain serum, which was analyzed to detect concentrations of antibodies against MH leukotoxin and BHV-1.
Results—In experiment 1, antibody titers against MH leukotoxin in calves receiving MH and ML virus vaccine appeared decreased, albeit nonsignificantly, compared with titers for calves receiving MH preparations alone. In experiment 2, all groups (except for 1) concurrently receiving an MH preparation and viral vaccine had a significant decrease in antibodies against MH leukotoxin. In both experiments, there was a significant decrease in the number of calves responding to MH leukotoxin when ML viral vaccine was coadministered.
Conclusions and Clinical Relevance—Coadministration of ML BHV-1 and MH preparations interfered with the serologic response to MH leukotoxin in calves seronegative for BHV-1. Serologic response to MH leukotoxin may be substantially improved in seronegative calves when MH vaccination is delayed until after calves have received a dose of ML BHV-1 vaccine.