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  • Author or Editor: Thomas J. Keefe x
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Abstract

Objective—To evaluate effects of meloxicam on severity of lameness and other clinical signs in dogs with osteoarthritis (OA).

Design—Randomized, controlled, multicenter clinical trial.

Animals—217 client-owned dogs with clinical and radiographic signs of OA.

Procedure—Dogs were randomly assigned to be treated with meloxicam (n = 105; 0.2 mg/kg [0.09 mg/lb], SC, once on day 1, then 0.1 mg/kg [0.045 mg/lb], PO, q 24 h, for 13 days) or a placebo (n = 112). A general clinical score was assigned by investigators on days 1 (ie, prior to initiation of treatment), 8, and 15 on the basis of severity of lameness, extent of weight bearing, and severity of signs during palpation of the affected joint. Owners and investigators provided overall evaluations on days 8 and 15.

Results—Dogs treated with meloxicam had significantly greater improvements in general clinical scores, compared with baseline scores, on days 8 and 15 than did dogs treated with placebo. On days 8 and 15, percentages of dogs treated with meloxicam in which owners and investigators considered treatment to be successful were significantly higher than percentages of control dogs in which treatment was considered to be successful. No abnormalities in hematologic and serum biochemical test results were detected.

Conclusions and Clinical Relevance—Results suggest that compared with administration of a placebo, administration of meloxicam for 14 days significantly improved the clinical condition of dogs with OA without causing adverse effects. ( J Am Vet Med Assoc 2004;225:1056–1060)

Full access
in Journal of the American Veterinary Medical Association

Abstract

Objective

To examine the ability of meloxicam, a cyclooxygenase inhibitor, to mediate the effects of sodium urate-induced acute stifle synovitis in dogs.

Animals

12 clinically normal adult hound-type dogs.

Procedure

A blinded, randomized, controlled single crossover design study was performed to determine the efficacy of meloxicam, using 2 dosage groups. In 2 experimental phases, dogs, according to group, received meloxicam (0.1 or 0.5 mg/kg of body weight) or matched volume of meloxicam vehicle, with a washout period of 21 to 28 days between phases. Blood samples for hematologic and biochemical analysis, as well as synovial fluid for cytologic analysis, were collected immediately before and approximately 24 hours after articular challenge of dogs under propofol anesthesia. Ground reaction forces (GRF) and subjective clinical scores were determined before and at 4, 8, 12, and 24 hours after articular challenge. Vertical force data included peak force, impulse, limb loading, and unloading rates. Craniocaudal data were divided into braking and propulsion phases and consisted of peak force and associated impulses.

Results

Except for propulsion impulse at 24 hours, all GRF variables were significantly greater at all postsynovitis induction times in the group receiving the high meloxicam dose. Significant differences in all GRF variables were seen at various times between the low-dose meloxicam group and the corresponding control group, and between the low- and high-dose meloxicam groups. Similar significance was seen in the subjective clinical evaluations. Strong correlations existed between the subjective and objective data.

Conclusions

Meloxicam was effective in attenuating the effects of sodium urate-induced acute synovitis in dogs. Kinetic gait data provided an objective measurement of lameness in an experimentally induced arthritis model and quantified lameness improvements in response to medication with a nonsteroidal anti-inflammatory drug. (Am J Vet Res 1997;58:626–631)

Free access
in American Journal of Veterinary Research

Abstract

Objective—To assess the microcirculatory effects of IV fluid administration in healthy anesthetized dogs undergoing elective ovariohysterectomy.

Animals—49 client-owned dogs.

Procedures—Dogs were sedated, and anesthesia was induced with propofol and diazepam and maintained with isoflurane in oxygen. Dogs received lactated Ringer's solution (LRS) IV at rates of 0, 10, or 20 mL/kg/h. Videomicroscopy was used to assess and record effects of LRS administration on microcirculation in the buccal mucosa. Measurements of microcirculatory (total vessel density, proportion of perfused vessels, microcirculatory flow index, and perfused vessel density by vessel size [< 20 μm, ≥ 20 μm, and all diameters]) and other physiologic variables (heart rate, Doppler-measured blood pressure, oxygen saturation as measured by pulse oximetry, capillary refill time, and body temperature) were compared among groups at baseline (immediately after anesthetic induction), 30 and 60 minutes afterward, and overall.

Results—Neither the proportion of perfused vessels nor microcirculatory flow index varied among treatment groups at any time point, regardless of vessel size. For vessels < 20 μm in diameter and for all vessels combined, total and perfused vessel density were similar among groups. For vessels ≥ 20 μm in diameter, total vessel density was significantly greater in the 20 mL/kg/h group than in other groups, and perfused vessel density was significantly greater in the 20 mL/kg/h group than in the 0 mL/kg/h group, when all time points were considered. Other physiologic variables were similar among groups.

Conclusions and Clinical Relevance—Total and perfused vessel density of vessels ≥ 20 μm in diameter (mostly venules) were greatest in dogs that received 20 mL of LRS/kg/h. Further research is required to evaluate clinical importance of these findings.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To evaluate the effectiveness of various sampling techniques for determining antimicrobial resistance patterns in Escherichia coli isolated from feces of feedlot cattle.

Sample Population—Fecal samples obtained from 328 beef steers and 6 feedlot pens in which the cattle resided.

Procedure—Single fecal samples were collected from the rectum of each steer and from floors of pens in which the cattle resided. Fecal material from each single sample was combined into pools containing 5 and 10 samples. Five isolates of Escherichia coli from each single sample and each pooled sample were tested for susceptibility to 17 antimicrobials.

Results—Patterns of antimicrobial resistance for fecal samples obtained from the rectum of cattle did not differ from fecal samples obtained from pen floors. Resistance patterns from pooled samples differed from patterns observed for single fecal samples. Little pen-to-pen variation in resistance prevalence was observed. Clustering of resistance phenotypes within samples was detected.

Conclusions and Clinical Relevance—Studies of antimicrobial resistance in feedlot cattle can rely on fecal samples obtained from pen floors, thus avoiding the cost and effort of obtaining fecal samples from the rectum of cattle. Pooled fecal samples yielded resistance patterns that were consistent with those of single fecal samples when the prevalence of resistance to an antimicrobial was > 2%. Pooling may be a practical alternative when investigating patterns of resistance that are not rare. Apparent clustering of resistance phenotypes within samples argues for examining fewer isolates per fecal sample and more fecal samples per pen. (Am J Vet Res 2002;63:1662–1670)

Full access
in American Journal of Veterinary Research
in American Journal of Veterinary Research

Abstract

Objective—To assess the likelihood of an introduction of foot-and-mouth disease (FMD) into the Malaysia-Thailand-Myanmar (MTM) peninsula through terrestrial movement of livestock.

Animals—89,294 cattle and buffalo legally moved into the MTM peninsula.

Procedures—A quantitative risk assessment was conducted by use of a stochastic simulation. Patterns of livestock movement were ascertained through review of relevant governmental records and regulations and by interviewing farmers, traders, and local officers when the records did not exist. Parameters identified in the process were the probabilities of livestock having FMD and of FMD infection going undetected during import processes. The probability of an animal accepted for import having FMD was also assessed. Sensitivity analysis was performed to determine the effects that each parameter had on the model.

Results—The simulation yielded an average consignment prevalence of 10.95%. Typically, each animal in a quarantine facility had a 2.7% chance of having an inapparent form of FMD infection; hence, it was likely an animal would not be identified as infected. Findings revealed that the mean probability of an animal accepted for import having FMD was 2.9%, and the risk was as high as 11%.

Conclusions and Clinical Relevance—Results of the model allowed for the evaluation of movement regulations currently imposed in the MTM peninsula. Evidence from the study suggested that current practices in animal movement were far from efficient in preventing introduction of FMD-infected animals into the MTM region, and additional measures will be necessary.

Full access
in American Journal of Veterinary Research

Abstract

Objective

To develop appropriate reference ranges for plasma IgG concentrations of llamas.

Animals

643 llamas on 5 farms.

Procedure

Plasma IgG concentration was measured by using a single radial immunodiffusion assay kit. Farm of origin, age, body condition score, and sex were recorded for each llama. The effect of each factor on plasma IgG concentration was evaluated separately, using ANOVA; the association between age and IgG concentration was evaluated, using linear regression. Multivariable regression models were developed to examine concurrent effects of age, sex, body condition score, farm, and various interactions on IgG concentration.

Results

The IgG concentrations were between 127 and 3,969 mg/dl. In llamas < 12 months old, farm of origin accounted for 29% of variability for IgG concentration. Reference range for plasma IgG concentrations in llamas < 12 months old was 391 to 2,357 mg/dl; for llamas > 12 but < 28 months old was 771 to 2,796 mg/dl; and for llamas > 28 months old was 570 to 3,264 mg/dl. These ranges were applicable only for the kit used in this study.

Conclusions

Healthy llamas have a wide range of IgG concentrations. Determinants of IgG concentration are multifactorial, and their importance varies with age of the llamas.

Clinical Implications

The wide range of IgG concentrations observed in healthy llamas and the influence that age and farm may have on IgG concentrations indicate that a result for one specific llama should be interpreted in relation to those of its herdmates. (Am J Vet Res 1998;59:406–409)

Free access
in American Journal of Veterinary Research

Summary

An elisa was compared with the plaque-reduction serum neutralization (prsn) test, for detection of vesicular stomatitis virus (vsv) antibodies in cattle in a vesicular stomatitis enzootic region of Mexico. A total of 325 bovine serum samples were screened for vsv antibodies. The prsn test was performed, using Vero cells. The elisa contained gradient-purified vsv Indiana (Lab strain) and vsv New Jersey (Hazelhurst) as the antigens. Regression analysis and weighted kappa statistic were used to estimate measures of agreement between the 2 assays for detection of vsv antibodies. The elisa method proved useful for sero-diagnosis of vesicular stomatitis The elisa and prsn test results were highly correlated for detection of vsv antibodies.

Free access
in American Journal of Veterinary Research

Objective

To evaluate analgesic and sedative effects of medetomidine hydrochloride in dogs and to compare effects with those of xylazine hydrochloride.

Design

Randomized, controlled trial.

Animals

184 dogs that required sedation or analgesia for completion of minor diagnostic or therapeutic procedures.

Procedure

Dogs were sedated with medetomidine, IV (750 μg/m2 of body surface area) or IM (1,000 µg/m2) or with xylazine, IV (1.1 mg/kg [0.5 mg/lb] of body weight) or IM (2.2 mg/kg [1 mg/lb]). Sedative effects were measured by scoring posture and response to noise. Durations of effects were determined by measuring time intervals between drug administration and changes in posture. Analgesic effects were measured by determining toe-pinch pressure needed to elicit a withdrawal response. Clinicians rated sedative and analgesic effects and ease with which diagnostic or therapeutic procedures could be performed.

Results

Posture and response to noise scores were significantly higher for dogs given medetomidine, IM, than for dogs given xylazine, IM, and for dogs given medetomidine, IV, than for dogs given xylazine, IV. Time to regaining sternal recumbency and time to regaining ability to stand were longest after IM administration of medetomidine. Toe-pinch pressures were not significantly different among groups. Clinicians rated overall analgesic and sedative effects as excellent significantly more often after administration of medetomidine than after administration of xylazine. Prevalence of adverse effects did not differ among groups.

Clinical Implications

Medetomidine and xylazine, at doses tested, were effective and safe, but results of subjective measurements indicated that medetomidine provided better sedation and analgesia than did xylazine. Specific α2-adrenergic antagonists (atipamezole, yohimbine) are available for control of adverse cardiovascular effects. (J Am Vet Med Assoc 1997;211:1413–1417)

Free access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To assess the impacts of the introduction of foot-and-mouth disease (FMD) and various FMD control programs in southern Thailand.

Animals—A native population of 562,910 cattle and 33,088 buffalo as well as 89,294 animals legally transported into southern Thailand.

Procedures—A quantitative risk assessment was used to ascertain the probability of FMD introduction, and an intrinsic dynamic model was used to assess impacts. Value for the transmission rate (β) was estimated. Five scenarios created to assess the impacts of nonstructural protein (NSP) testing, mass vaccination, and culling were examined. Impacts were assessed through an examination of the estimated annual cumulative incidence (ACI) of FMD. The ACIs of various scenarios were compared by use of the Tukey Studentized range technique.

Results—β was estimated at 0.115. Approximately 35,000 cases of FMD would be expected from the baseline situation. A 30% reduction of ACI was detected with the introduction of NSP antibody testing. Prophylactic vaccination resulted in an 85% reduction of ACI. Concurrent use of NSP antibody testing and vaccination reduced the ACI by 96%, and the addition of an eradication policy resulted in a slightly greater decrease in the ACI (98%).

Conclusions and Clinical Relevance—The study used epidemiologic models to investigate FMD control interventions. Results suggested that vaccination has more impact than the use of NSP testing. Use of the NSP test reduced ACI during peak seasons, whereas vaccination diminished the underlying incidence. The best mitigation plan was an integrated and strategic use of multiple control techniques.

Full access
in American Journal of Veterinary Research