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Abstract

OBJECTIVE

To determine epidemiological features of cardiovascular disease in rabbits examined at a veterinary teaching hospital and characterize clinical and pathological findings.

ANIMALS

59 rabbits.

PROCEDURES

Medical records from 2001 to 2018 were reviewed, and data were collected. Echocardiographic images and histologic diagnoses were reviewed.

RESULTS

The prevalence of cardiovascular disease was 2.6% (59/2,249). Clinical signs related to cardiac disease included heart murmur (n = 25 rabbits), arrhythmia (22), tachypnea or dyspnea (13), hyporexia or anorexia (13), and muscle wasting (9). Radiographic (n = 39) abnormalities included cardiomegaly (19) and peritoneal (12) and pleural (11) effusion. Common echocardiographic (n = 37) diagnoses included degenerative valve disease (15), dilated cardiomyopathy (7), unclassified cardiomyopathy (4), restrictive cardiomyopathy (3), and hypertrophic cardiomyopathy (2). On ECG (n = 19), supraventricular arrhythmias (16) were more common than ventricular arrhythmias (12). Thirty-five necropsy reports were available, and diagnoses included cardiomyopathy (n = 14), myocarditis (10), and arteriosclerosis (9). Medical management (n = 20) included a wide range of drugs and dosages with few adverse effects. Survival times (n = 36 rabbits) ranged from 1 to 2,353 days with a median cardiac disease–specific survival time of 306 days.

CONCLUSIONS AND CLINICAL RELEVANCE

The findings provided information on the prevalence of cardiovascular disease in rabbits and survival times for affected rabbits. Right-sided, left-sided, and biventricular congestive heart failure occurred equally. Median survival time was lower than that reported for other species. Further research on the diagnosis and treatment of cardiovascular disease in rabbits is needed.

Full access
in Journal of the American Veterinary Medical Association
in Journal of the American Veterinary Medical Association

Abstract

OBJECTIVE To determine the pharmacokinetics and adverse effects at the injection site of ceftiofur crystalline-free acid (CCFA) following IM administration of 1 dose to red-tailed hawks (Buteo jamaicensis).

ANIMALS 7 adult nonreleasable healthy red-tailed hawks.

PROCEDURES In a randomized crossover study, CCFA (10 or 20 mg/kg) was administered IM to each hawk and blood samples were obtained. After a 2-month washout period, administration was repeated with the opposite dose. Muscle biopsy specimens were collected from the injection site 10 days after each sample collection period. Pharmacokinetic data were calculated. Minimum inhibitory concentrations of ceftiofur for various bacterial isolates were assessed.

RESULTS Mean peak plasma concentrations of ceftiofur-free acid equivalent were 6.8 and 15.1 μg/mL for the 10 and 20 mg/kg doses, respectively. Mean times to maximum plasma concentration were 6.4 and 6.7 hours, and mean terminal half-lives were 29 and 50 hours, respectively. Little to no muscle inflammation was identified. On the basis of a target MIC of 1 μg/mL and target plasma ceftiofur concentration of 4 μg/mL, dose administration frequencies for infections with gram-negative and gram-positive organisms were estimated as every 36 and 45 hours for the 10 mg/kg dose and every 96 and 120 hours for the 20 mg/kg dose, respectively.

CONCLUSIONS AND CLINICAL RELEVANCE Study results suggested that CCFA could be administered IM to red-tailed hawks at 10 or 20 mg/kg to treat infections with ceftiofur-susceptible bacteria. Administration resulted in little to no inflammation at the injection site. Additional studies are needed to evaluate effects of repeated CCFA administration.

Full access
in American Journal of Veterinary Research

Abstract

OBJECTIVE To describe the prevalence, histologic characteristics, concomitant abnormalities, and outcomes for various types of mammary gland tumors in companion rats (Rattus norvegicus).

DESIGN Retrospective case series.

ANIMALS 100 client-owned rats.

PROCEDURES Medical records of companion rats that had an SC mass and were examined at a veterinary teaching hospital between 1990 and 2015 were reviewed. Information regarding the signalment, age at mass detection, reproductive sterilization status, histologic diagnosis of the SC mass, location of the initial and all subsequent SC masses, treatments administered, and clinical outcomes was extracted from each record and summarized.

RESULTS 105 SC masses were initially detected in 100 rats. The most prevalent SC mass identified was mammary gland fibroadenoma (56/105 [53%]), followed by mammary gland carcinoma (13/105 [12%]). Overall, 26 of 105 (25%) masses were malignant. Sexually intact males were more likely to have nonmammary SC tumors than sexually intact females. In rats receiving no adjunctive treatment after excision of a mammary gland fibroadenoma (n = 16), a second fibroadenoma was detected 1 to 8 months after initial excision, at a median of 4.5 months after surgery. A concomitant pituitary gland tumor was identified in most rats with mammary gland fibroadenoma (21/28 [75%]) and other types of mammary gland tumors (10/17 [59%]). Fourteen of 35 (40%) rats with mammary gland fibroadenoma had concomitant reproductive tract abnormalities.

CONCLUSION AND CLINICAL RELEVANCE Results suggested that, like other species, companion rats with SC masses should undergo a thorough diagnostic workup that includes histologic examination of the excised mass.

Full access
in Journal of the American Veterinary Medical Association

Abstract

OBJECTIVE

To determine the clinical and pathological findings of rabbits diagnosed with lymphoma.

ANIMALS

16 rabbits.

PROCEDURES

The medical and pathology records database of the Veterinary Medical Teaching Hospital at the University of California, Davis was searched for rabbits diagnosed with lymphoma from 1996 to 2019.

RESULTS

Mean age of the 16 rabbits was 8 years (range, 4.5 to 12 years). Immunophenotyping was performed in 14 cases. Diffuse, large, B-cell lymphoma was most common (n = 7) followed by epitheliotropic, T-cell lymphoma (2); type II enteropathy-associated, T-cell lymphoma (2); marginal-zone, B-cell lymphoma (1); peripheral, T-cell lymphoma not otherwise specified (cutaneous nonepitheliotropic lymphoma; 1); primary, mediastinal (thymic) large B-cell lymphoma (1), and unclassified (cytology only with no immunophenotyping; 2). Multiple chemotherapy protocols were used on the basis of each individual animal’s disease state. Initial clinical improvement was reported for most rabbits receiving chemotherapy (5/6), with diffuse B-cell lymphoma responding most favorably to treatment. The 11 rabbits included in the survival analysis had a median survival time of 60 days (range, 1 to 480 days), and those diagnosed with B- and T-cell lymphoma had a median survival time of 8 and 36 days (range, 1 to 150 and 1 to 90 days), respectively.

CLINICAL RELEVANCE

Rabbits develop a range of lymphoma subtypes and, similar to humans and dogs, diffuse large B-cell lymphoma appears to be the most common. Chemotherapy treatments followed multiple protocols, which were mostly well tolerated and had a highly variable response. Further research into chemotherapy protocols is needed to optimize treatment of lymphoma in rabbits.

Full access
in Journal of the American Veterinary Medical Association

Abstract

OBJECTIVE

To investigate associations between hepatic fat accumulation, fibrosis, and plasma values of primary metabolites, biochemical measurands, insulin, and lipoproteins in bearded dragons.

ANIMALS

48 adult central bearded dragons (Pogona vitticeps).

METHODS

Dragons were sedated with alfaxalone, and a blood sample was collected. Plasma was submitted for untargeted primary metabolomics using gas chromatography time-of-flight mass spectrometry, a biochemistry panel, and a lipoprotein panel determined by PAGE. Hepatic lipid content was quantified by liver attenuation measurements from CT images and digital image analysis of standardized histologic sections of the liver. Fibrosis was quantified by digital image analysis on Masson’s trichrome–stained histologic sections. Severity was determined from pathologic review of liver sections according to a standardized grading system. Statistical associations were investigated using serial linear models adjusted for false discovery rate and multivariate statistics.

RESULTS

Both hepatic fat and fibrosis had a significant effect on CT liver attenuation values. Several oligosaccharides (maltotriose, maltose, ribose, trehalose) and alkaline phosphatase were significantly and linearly increased with hepatic lipid content (all q < .05). On partial least square–discriminant analysis, β-hydroxybutyric acid was the most important discriminatory variable between fatty liver severity grades on histology. No significant associations were found with insulin, lipoproteins, and succinic acid.

CLINICAL RELEVANCE

Bearded dragons with hepatic lipid accumulation experienced multiple metabolic pathway disruptions, some being compatible with mitochondrial dysfunction. No evidence of insulin resistance or dyslipidemia was found. Hepatic biopsy and histopathology remain recommended for reliably diagnosing and staging fatty liver disease in bearded dragons.

Open access
in American Journal of Veterinary Research

Abstract

OBJECTIVE To compare intraosseous pentobarbital treatment (IPT) and thoracic compression (TC) on time to circulatory arrest and an isoelectric electroencephalogram (EEG) in anesthetized passerine birds.

ANIMALS 30 wild-caught adult birds (17 house sparrows [Passer domesticus] and 13 European starlings [Sturnus vulgaris]).

PROCEDURES Birds were assigned to receive IPT or TC (n = 6/species/group). Birds were anesthetized, and carotid arterial pulses were monitored by Doppler methodology. Five subdermal braided-wire electrodes were used for EEG. Anesthetic depth was adjusted until a continuous EEG pattern was maintained, then euthanasia was performed. Times from initiation of euthanasia to cessation of carotid pulse and irreversible isoelectric EEG (indicators of death) were measured. Data (medians and first to third quartiles) were summarized and compared between groups within species. Necropsies were performed for all birds included in experiments and for another 6 birds euthanized under anesthesia by TC (4 sparrows and 1 starling) or IPT (1 sparrow).

RESULTS Median time to isoelectric EEG did not differ significantly between treatment groups for sparrows (19.0 and 6.0 seconds for TC and IPT, respectively) or starlings (88.5 and 77.5 seconds for TC and IPT, respectively). Median times to cessation of pulse were significantly shorter for TC than for IPT in sparrows (0.0 vs 18.5 seconds) and starlings (9.5 vs 151.0 seconds). On necropsy, most (14/17) birds that underwent TC had grossly visible coelomic, pericardial, or perihepatic hemorrhage.

CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that TC might be an efficient euthanasia method for small birds. Digital pressure directly over the heart during TC obstructed venous return, causing rapid circulatory arrest, with rupture of the atria or vena cava in several birds. The authors propose that cardiac compression is a more accurate description than TC for this procedure.

Full access
in American Journal of Veterinary Research