Introduction: The purpose of this study was to investigate the therapeutic effect of hydrogen on the therapy of onion poisoned dogs. Material and Methods: A total of 16 adult beagle dogs were divided into two groups (control and hydrogen) and all were fed dehydrated onion powder at the dose of 10 g/kg for three days. The dogs of the experimental group were given subcutaneous injection of 0.2 mL/kg of hydrogen for 12 days after making the poisoned model successful. Blood samples were collected before feeding onions, one day before injecting hydrogen, and 2 h after the injection of hydrogen on days 1, 3, 5, 7, 9, and 12. Control dogs were not treated with hydrogen. Results: The levels of leukocyte production, anaemia, red blood cell degeneration which was reflected by the values of Heinz body count, haemolytic ratio, and oxidative products in hydrogen treated group were lower than in control dogs on some days. The capacity of medullary haematopoiesis that was based on reticulocyte counts, and the antioxidation in hydrogen group were higher compared with control group. However, the differences in renal function were not obvious in both groups. Conclusion: Accordingly, it was concluded that subcutaneous injection of hydrogen could alleviate the symptoms in onion poisoned dogs.

OBJECTIVE To compare the pharmacokinetics of 2 commercial florfenicol formulations following IM and SC administration to sheep. ANIMALS 16 healthy adult mixed-breed sheep. PROCEDURES In a crossover study, sheep were randomly assigned to receive florfenicol formulation A or B at a single dose of 20 mg/kg, IM, or 40 mg/kg, SC. After a 2-week washout period, each sheep was administered the opposite formulation at the same dose and administration route as the initial formulation. Blood samples were collected immediately before and at predetermined times for 24 hours after each florfenicol administration. Plasma florfenicol concentrations were determined by high-performance liquid chromatography. Pharmacokinetic parameters were estimated by noncompartmental methods and compared between the 2 formulations at each dose and route of administration. RESULTS Median maximum plasma concentration, elimination half-life, and area under the concentration-time curve from time 0 to the last quantifiable measurement for florfenicol were 3.76 μg/mL, 13.44 hours, and 24.88 μg•h/mL, respectively, for formulation A and 7.72 μg/mL, 5.98 hours, and 41.53 μg•h/mL, respectively, for formulation B following administration of 20 mg of florfenicol/kg, IM, and 2.63 μg/mL, 12.48 hours, and 31.63 μg•h/mL, respectively, for formulation A and 4.70 μg/mL, 16.60 hours, and 48.32 μg•h/mL, respectively, for formulation B following administration of 40 mg of florfenicol/kg, SC. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that both formulations achieved plasma florfenicol concentrations expected to be therapeutic for respiratory tract disease caused by Mannheimia haemolytica or Pasteurella spp at both doses and administration routes evaluated.

Objective—To determine the pharmacokinetics of cefovecin sodium after SC administration to Hermann's tortoises (Testudo hermanni). Animals—23 healthy adult Hermann's tortoises (15 males and 8 females). Procedures—Cefovecin (8.0 mg/kg) was injected once in the subcutis of the neck region of Hermann's tortoises, and blood samples were obtained at predetermined time points. Plasma cefovecin concentrations were measured via ultraperformance liquid chromatography coupled to tandem mass spectrometry, and pharmacokinetic parameters were calculated with a noncompartmental model. Plasma protein concentration was quantified, and the percentage of cefovecin bound to protein was estimated with a centrifugation technique. Results—Cefovecin was absorbed rapidly, reaching maximum plasma concentrations between 35 minutes and 2 hours after administration, with the exception of 1 group, in which it was reached after 4 hours. The mean ± SD time to maximum concentration was 1.22 ± 1.14 hours; area under the concentration-time curve was 220.35 ± 36.18 h•μg/mL The mean protein-bound fraction of cefovecin ranged from 41.3% to 47.5%. No adverse effects were observed. Conclusions and Clinical Relevance—Administration of a single dose of cefovecin SC appeared to be well-tolerated in this population of tortoises. Results of pharmacokinetic analysis indicated that the 2-week dosing interval suggested for dogs and cats cannot be considered effective in tortoises; however, further research is needed to determine therapeutic concentrations of the drug and appropriate dose ranges.

Cortical bone concentrations of enrofloxacin were determined over time in dogs after SC administration of the drug. Nineteen healthy adult dogs were anesthetized and were given 2.5 or 5.0 mg of enrofloxacin/kg of body weight, SC. Serial serum and bone samples were obtained for determination of enrofloxacin concentrations at intervals until 8 hours after drug administration. Cortical bone samples were procured by surgical disarticulation of successive second phalanges. Additional cortical bone samples were taken from long bones in 4 dogs. Mean +/- SD peak serum enrofloxacin concentration was 0.54 +/- 0.10 micrograms/ml for the 2.5-mg/kg dosage and 0.97 +/- 0.34 micrograms/ml for the 5.0-mg/kg dosage. Serum concentration was significantly higher than bone concentration for each dosage. Mean peak bone concentrations reached 29% of peak serum values: 0.15 +/- 0.09 micrograms/g and 0.29 +/- 0.09 micrograms/g for 2.5-mg/kg and 5.0-mg/kg dosages, respectively. Serum concentration for the 5.0-mg/kg dosage was significantly greater than that for the 2.5-mg/kg dosage for all times, whereas bone concentrations for the 5.0-mg/kg dosage were significantly higher at all times after 180 minutes. For the duration of the study, cortical bone concentrations of enrofloxacin at either dosage exceeded the minimum inhibitory concentration (MIC) for the Enterobacteriaceae, but reliably exceeded the MIC for Staphylococcus sp only at the 5.0-mg/kg dosage. At no time did cortical bone concentrations of enrofloxacin exceed the MIC for Pseudomonas aeruginosa at either dosage. To validate extrapolation of data from the second phalanx to long bones and from anesthetized to awake dogs, 16 healthy dogs being euthanatized in unrelated studies were given 2.5 or 5.0 mg of enrofloxacin/kg, sc. These dogs were not anesthetized but were euthanatized at 60, 120, or 240 minutes after drug administration, and multiple cortical bone samples were taken. Antibiotic concentrations in the second phalanx were not significantly different from those in long bones. Comparison of enrofloxacin concentrations in cortical bone of awake and anesthetized dogs suggested no differences between groups. We concluded that general anesthesia and use of the antibiotic concentrations in the second phalanx as representative of those in long bones did not affect results of this study.

Efficacy of abamectin against gastrointestinal tract nematodes and lungworms of cattle was determined in 4 experiments. The first 2 experiments were controlled trials in which efficacy was determined at necropsy in calves with either experimentally induced (n = 14) or naturally acquired (n = 16) infections. Half the calves in each experiment were treated with abamectin (200 micrograms/kg of body weight, sc), and half were left untreated as controls. Efficacy was > 99% against adult stages of Dictyocaulus viviparus, Haemonchus placei, Ostertagia ostertagi, Trichostrongylus axei, Cooperia punctata, Trichuris discolor, and C oncophora, and was 92.4% against Nematodirus helvetianus. The second 2 experiments were clinical trials in which efficacy was determined by fecal egg count reduction in naturally infected yearling heifers (n = 75) or 2-year-old heifers (n = 75). Within replicates of 5, 4 heifers were assigned at random to treatment with 200 Kg of abamectin/kg and 1 was left untreated as a control. Abamectin was 100% effective in eliminating strongylate nematode eggs from the feces of these heifers. In all experiments, adverse reactions were limited to small, clinically unimportant injection site swellings in 29% of abamectin-treated calves. Abamectin was judged to be safe and effective in these trials.

OBJECTIVE To determine the thermal antinociceptive effects of butorphanol tartrate and butorphanol tartrate in a sustained-release 25% poloxamer 407 (P407) gel formulation (But-P407) in parrots. ANIMALS 13 orange-winged Amazon parrots (Amazona amazonica). PROCEDURES First, butorphanol tartrate (5 mg/kg) or saline (0.9% NaCl) solution was administered IM to birds in a randomized complete crossover design. The temperature prompting a foot withdrawal response to a thermal stimulus (ie, the thermal threshold) was determined 30 minutes before (baseline) and at various points after treatment administration. Second, But-P407 (12.5 mg/kg) or P407 was administered SC in a similar crossover design. Thermal threshold was determined before and at various points after treatment administration. Third, But-P407 (12.5 mg/kg) or saline solution was administered SC and evaluated as in the second trial. Sedation was scored immediately before each time point in all 3 trials. RESULTS In the first trial, a significant increase in thermal threshold was noted 30 minutes after butorphanol tartrate (vs saline solution) administration. No sedation was noted. In the second and third trials, no significant difference was identified between results for But-P407 and those for either control treatment (saline solution or P407). Mild sedation was noted in the second trial following But-P407 administration. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested a small but significant thermal antinociceptive effect of butorphanol tartrate lasting between 30 minutes and 1.5 hours in orange-winged Amazon parrots. No antinociceptive effect of butorphanol tartrate was demonstrated when delivered in P407. Further research is needed to evaluate the potential analgesic effects of But-P407.

OBJECTIVE To determine the pharmacokinetics of cefovecin sodium after SC administration of a single dose to African lions (Panthera leo). ANIMALS 3 adult (9 to 10 years old; 1 male and 2 females) and 3 juvenile (2 years old; 1 male and 2 females) African lions. PROCEDURES A crossover study was conducted. A single dose of cefovecin was administered SC at 4 mg/kg (half dose) and 8 mg/kg (full dose) to African lions. Blood samples were collected daily for 14 days after cefovecin injection. Plasma drug concentrations were determined by use of high-performance liquid chromatography with UV detection. RESULTS Cefovecin had first-order elimination kinetics for doses of 4 and 8 mg/kg. Mean ± SD maximum plasma concentration was 9.73 ± 1.01 μg/mL and 18.35 ± 0.94 μg/mL after doses of 4 and 8 mg/kg, respectively. Time to maximum plasma concentration was approximately 4 hours for both doses. Mean elimination half-life was approximately 111 and 115 hours after doses of 4 and 8 mg/kg, respectively. CONCLUSIONS AND CLINICAL RELEVANCE Cefovecin was detected in lion plasma for 336 hours after administration at both 4 and 8 mg/kg at concentrations greater than the reported minimum inhibitory concentration (0.06 μg/mL) for common bacterial organisms in domestic cats. These results indicated that cefovecin administered at 4 mg/kg SC reached therapeutic concentrations for an extended period in African lions.

OBJECTIVE To determine plasma concentrations of enrofloxacin and its active metabolite ciprofloxacin following single-dose SC administration to black-tailed prairie dogs (Cynomys ludovicianus). ANIMALS 8 captive healthy 6-month-old sexually intact male black-tailed prairie dogs. PROCEDURES Enrofloxacin (20 mg/kg) was administered SC once to 6 prairie dogs and IV once to 2 prairie dogs. A blood sample was collected from each animal immediately before (0 hours) and 0.5, 1, 2, 4, 8, 12, and 24 hours after drug administration to evaluate the pharmacokinetics of enrofloxacin and ciprofloxacin. Plasma enrofloxacin and ciprofloxacin concentrations were quantified with ultraperformance liquid chromatography–mass spectrometry, and noncompartmental pharmacokinetic analysis was performed. RESULTS Enrofloxacin was biotransformed to ciprofloxacin in the prairie dogs used in the study. For total fluoroquinolones (enrofloxacin and ciprofloxacin), the mean (range) of peak plasma concentration, time to maximum plasma concentration, and terminal half-life after SC administration were 4.90 μg/mL (3.44 to 6.08 μg/mL), 1.59 hours (0.5 to 2.00 hours), and 4.63 hours (4.02 to 5.20 hours), respectively. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that administration of enrofloxacin (20 mg/kg, SC, q 24 h) in black-tailed prairie dogs may be appropriate for treatment of infections with bacteria for which the minimum inhibitory concentration of enrofloxacin is ≤ 0.5 μg/mL. However, clinical studies are needed to determine efficacy of such enrofloxacin treatment.

The goal of the present study was to evaluate the potential use of slow release buprenorphine in sheep. Twelve adult female sheep (6 Dorset and 6 Suffolk, 12 months of age) were used for this project and were divided into 2 experimental groups (n = 6/group comprising 3 Dorset and 3 Suffolk sheep). Sustained release (SR) buprenorphine was administered subcutaneously in the scapular region at a concentration of 0.1 mg/kg body weight (BW) for group 1 and of 0.05 mg/kg BW for group 2. Following blood collections at selected time points, plasma concentrations of buprenorphine was performed by tandem liquid chromatograph-mass spectrometry. Mean buprenorphine concentration was above 0.1 ng/mL at 48 h up to 192 h post-injection for group 1 and it was above 0.1 ng/mL at 48 h up to 72 h post-injection for group 2. In conclusion, a long lasting potential analgesic plasma level of buprenorphine is attained following a single subcutaneous injection of 0.1 mg/kg BW of SR buprenorphine in sheep. However the effective analgesic plasma threshold still needs to be determined in sheep.

Objective—To determine pharmacokinetics of marbofloxacin in water buffalo calves (Bubalus bubalis) after multiple SC administrations and to assess differences in regimen efficacy. Animals—18 healthy buffalo calves. Procedures—Calves (n = 6 calves/group) were assigned to receive marbofloxacin SC in the neck at 1 of 3 dosages (2 mg/kg, q 24 h for 6 days [regimen 1]; 4 mg/kg, q 48 h for 6 days [regimen 2]; and 4 mg/kg, q 24 h for 3 days [regimen 3]). Serum marbofloxacin concentrations were analyzed. Efficacy predictors were estimated on the basis of minimum inhibitory concentration and mutant prevention concentration reported for Pasteurella multocida and Mannheimia haemolytica. Results—Mean ± SD area under the concentration-time curve was 5.92 ± 0.40 μg•h/mL for regimen 1, which differed significantly from that for regimens 2 (14.26 ± 0.92 μg•h/mL) and 3 (14.17 ± 0.51 μg•h/mL). Mean residence time and mean elimination half-life for regimen 2 (9.93 ± 0.20 hours and 8.77 ± 0.71 hours) both differed significantly from those for regimens 1 (721 ± 0.11 hours and 5.71 ± 0.38 hours) and 3 (759 ± 0.13 hours and 737 ± 1.19 hours). Values obtained from indices for P multocida and M haemolytica had an excessively wide range because of the various degrees of antimicrobial susceptibility (low, medium, and high) of the strains. Conclusions and Clinical Relevance—Regimen 3 had the most favorable indices, and it would be conducive for owner compliance and require less handling of animals.