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in Journal of the American Veterinary Medical Association


Objective—To assess accuracy and reliability of open-flow indirect calorimetry in dogs.

Animals—13 clinically normal dogs.

Procedure—In phase 1, oxygen consumption per kilogram of body weight (VO2kg) was determined in 6 anesthetized dogs by use of open-flow indirect calorimetry before and after determination of VO2/kg by use of closed-circuit spirometry. In phase 2, four serial measurements of VO2 and carbon dioxide production (VCO2) were obtained in 7 awake dogs by use of indirect calorimetry on 2 consecutive days. Resting energy expenditure (REE) was calculated.

Results—Level of clinical agreement was acceptable between results of indirect calorimetry and spirometry. Mean VO2/kg determined by use of calorimetry before spirometry was significantly greater than that obtained after spirometry. In phase 2, intraclass correlation coefficients (ICC) for REE and VO2 were 0.779 and 0.786, respectively, when data from all 4 series were combined. When the first series was discounted, ICC increased to 0.904 and 0.894 for REE and VO2, respectively. The most reliable and least variable measures of REE and VO2 were obtained when the first 2 series were discounted.

Conclusions and Clinical Relevance—Open-flow indirect calorimetry may be used clinically to obtain a measure of VO2 and an estimate of REE in dogs. Serial measurements of REE and VO2 in clinically normal dogs are reliable, but a 10-minute adaption period should be allowed, the first series of observations should be discounted, multiple serial measurements should be obtained, and REE. (Am J Vet Res 2001;62:1761–1767).

Full access
in American Journal of Veterinary Research


Objective—To determine whether free radicals are produced in ischemic and reperfused canine skeletal muscle, whether free radicals can be detected from effluent blood by use of spin-trapping electron paramagnetic resonance (EPR) spectroscopy, and whether free radical-induced skeletal muscle damage is detectable by use of light microscopy.

Animals—6 healthy mixed-breed dogs.

Procedures—Dogs were anesthetized and both gracilis muscles were isolated, leaving only the major vascular pedicle intact. Ischemia was induced in 1 flap for 4 hours; the contralateral flap served as the control. Ischemic flaps were then reperfused for 15 minutes. α-Phenyl-N-tert-butylnitrone, a spin-trapping agent, was administered intravenously to each dog 1 hour prior to reperfusion. Following reperfusion, effluent blood samples from muscle flaps were obtained and processed for EPR spectroscopy. Muscle biopsy specimens were obtained for histologic evaluation, and dogs were euthanatized.

Results—Spin adducts were not detected in blood from control flaps. However, spin adducts were detected in all ischemic-reperfused muscle flaps. Principal signals identified were characteristic of oxygen- and carbon-centered radicals. Significantly more muscle damage was detected in ischemic-reperfused flaps, compared with control flaps.

Conclusions and Clinical Relevance—Free radicals may be an important component of injury induced by ischemia and reperfusion of canine skeletal muscle. Spin-trap adducts of free radicals can be detected in effluent blood of canine muscle flaps by use of spin-trapping EPR spectroscopy. Spin-trapping EPR spectroscopy may be useful for the study of antioxidants and free radical scavengers in attenuating ischemia and reperfusionmediated skeletal muscle damage. (Am J Vet Res 2001;62:384–388)

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in American Journal of Veterinary Research


Objective—To determine whether adenosine pretreatment attenuates free radical production and muscle damage in ischemic and reperfused canine skeletal muscle.

Animals—9 healthy mixed-breed dogs.

Procedure—Dogs were anesthetized, and both gracilis muscles were isolated, leaving only the major vascular pedicle intact. Saline (0.9% NaCl) solution was injected into the artery supplying the control flap, whereas adenosine (10 mg) was injected into the contralateral artery. Ischemia was induced in both flaps for 4 hours. α-Phenyl-N-tert-butylnitrone was administered IV to each dog 1 hour prior to reperfusion. Following 15 minutes of reperfusion, effluent blood samples from each muscle flap were obtained and processed for spin-trapping electron paramagnetic resonance (EPR) spectroscopy. Muscle biopsy specimens were obtained for histologic evaluation, and dogs were euthanatized.

Results—EPR spectra of strong intensity were obtained from analysis of 5 of 9 paired samples. Signals identified were characteristic of oxygen- and carbon-centered free radical adducts. Signal intensity of spectra from adenosine-treated flaps was significantly less than that of control flaps; mean signal attenuation was 36% in the adenosine-treated group. Histologic evaluation of muscle flaps did not reveal significant differences between groups.

Conclusions and Clinical Relevance—Treatment of canine muscle flaps with adenosine prior to a period of ischemia reduced but did not completely attenuate free radical production after reperfusion. However, adenosine pretreatment did not affect histologic abnormalities. (Am J Vet Res 2002;63:175–180)

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in American Journal of Veterinary Research


Objective—To determine the level of clinical agreement between 2 methods for the measurement of resting energy expenditure (REE).

Design—Prospective case series.

Animals—77 dogs.

Procedure—Oxygen consumption (O2) and CO2 production (CO2) were measured with an open-flow indirect calorimeter in healthy (n = 10) and ill (67) dogs. Measurements were collected at 3 time periods on 2 days. The O2 and the CO2 measurements were then used to calculate the REE values.

Results—Mean values of measured (MREE) and predicted (PREE) REEs in healthy dogs and a dog with medical illnesses or trauma were not significantly different. There was a significant difference on day 2 between the MREE and PREE in the group of dogs recovering from major surgery. More importantly, there was significant variation between the PREE and MREE on an individual-dog basis. The PREE only agreed to within ± 20% of the MREE in 51% to 57% of the dogs.

Conclusions and Clinical Relevance—The level of agreement between these two methods for determining the 24-hour REE was poor in individual dogs. The level of disagreement between the 2 methods indicates that these methods may not be used interchangeably in a clinical setting. Measurement of REE by use of indirect calorimetry may be the only reliable method of determining REE in an individual ill or healthy dog. (J Am Vet Med Assoc 2004;225:58–64)

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in Journal of the American Veterinary Medical Association



This study aimed to characterize the bacterial and eukaryotic microbiota of the gastrointestinal (GI) tract in domestic rabbits and to evaluate the effect of different diet characteristics, such as pelleting, extrusion, and hay supplementation.


30 New Zealand White rabbits (15 male and 15 female; 6 to 7 months old) were fed 1 of 6 diets (5 rabbits per diet) for 30 days after an initial acclimation period. At the end of the trial, samples were collected from the stomach, small intestine, cecum, large intestine, and hard feces.


The samples were analyzed using 16S rRNA and internal transcribed spacer 1 region-targeted amplicon sequencing.


The bacterial microbiota was distinct between the foregut and hindgut. The most abundant bacterial genera included an unclassified genus in the Bacteroidales order and Alistipes. Candida was the most abundant genus in the eukaryotic dataset. In the bacterial dataset, diet No Hay/Pellet E was shown to have lower diversity (Shannon diversity, P < .05) compared to all diet groups except for No Hay/Pellet M. Few significant differences in alpha-diversity indexes between diet groups were detected in the eukaryotic dataset.


Our findings demonstrated that feeding hay had a significant effect on the beta diversity of the bacterial microbiota. Given the prevalence of gastrointestinal disease in the domestic rabbit population, furthering our understanding of what constitutes a healthy rabbit microbiota and the effects of different diets on the microbial community can help veterinarians implement better intervention strategies and allow pet owners to provide the best level of care.

Open access
in American Journal of Veterinary Research


Objective—To evaluate concordance among veterinary pathologists in the assessment of histologic findings in the pars intermedia of pituitary gland sections from aged horses with mild signs suggestive of pituitary pars intermedia dysfunction (PPID).

Sample Population—10 pituitary glands from aged horses.

Procedure—7 pathologists were provided with signalment, clinical signs, and a single H&E-stained pituitary gland section from 10 aged horses with mild signs suggestive of PPID. Pathologists described histologic findings for each section and stated whether findings were consistent with PPID. Agreement among pathologists and with antemortem diagnostic test results was calculated.

Results—Overall, only fair agreement was found among the pathologists as to which horses had histologic findings consistent with disease (mean ± SE kappa value, 0.34 ± 0.069). Interpretation of individual sections varied, with minimal agreement (4 or 5/7 pathologists) for 5 of 10 sections evaluated. Postmortem assessment was in agreement with an antemortem endocrine diagnostic test result 79% of the time.

Conclusions and Clinical Relevance—Validation of antemortem diagnostic testing for PPID in horses often relies on the results of postmortem histologic evaluation. The lack of consensus in histologic interpretation of pituitary glands from aged horses with mild clinical signs in our study indicates that postmortem histologic evaluation of pituitary glands is an inappropriate standard in validation of antemortem diagnostic tests for detection of early PPID. Caution should be used when interpreting diagnostic test results in horses in which early PPID is suspected. (Am J Vet Res 2005;66:2055–2059)

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in American Journal of Veterinary Research


Albendazole (10 mg/kg of body weight) was administered as a drench suspension or as a feed additive to 24 cattle with naturally acquired infections of Fasciola hepatica and Fascioloides magna. Cattle were euthanatized 16 to 30 days after treatment, and the number of viable flukes was counted. Viable F hepatica and F magna were decreased by 91.4% and 70.6% for drench administration and by 82.9% and 71.9% for the feed additive treatment, respectively. There was no significant difference between the efficacy of the 2 formulations in decreasing viable fluke numbers, compared with untreated controls.

Free access
in American Journal of Veterinary Research


To determine the clinical, pathologic, and bacteriologic findings in dogs that developed severe invasive infections with group G streptococci (GGS) over a 6-month period in southern Ontario.


Prospective case series.


7 dogs in southern Ontario with severe streptococcal infection during a 6-month period.


Using pulsed-field gel electrophoresis, molecular typing of streptococcal isolates was performed. Isolates were examined for the M protein gene emm1.0, pyrogenic exotoxin genes speA, speB, speF, hyaluronic acid synthase genes hasA, hasB, and for C5a peptidase gene scpA by use of DNA probes or polymerase chain reaction.


3 dogs with streptococcal shock without necrotizing fasciitis died or were euthanatized within 48 hours of admission, whereas 4 dogs with streptococcal shock and necrotizing fasciitis survived following surgical debridement, supportive medical treatment, and treatment with antibiotics. Of the 6 Lancefield group G streptococcal isolates available for characterization, 5 were Streptococcus canis and 1 had characteristics of group G streptococcal strains of human origin. Results of molecular typing indicated that isolates were unrelated to each other. Examination of the canine isolates for putative virulence genes found in human group A streptococci resulted in identification of the the emm1.0 gene only in 1 of the isolates. The canine isolates otherwise lacked virulence genes associated with human group A streptococcal toxic shock infections.

Clinical Implications

The development of severe invasive infection in dogs resulting from GGS indicates that a virulent form of GGS has developed in southern Ontario. (J Am Vet Med Assoc 1996;209:1421–1426)

Free access
in Journal of the American Veterinary Medical Association