Objective—To determine the incidence of adverse
events in ferrets vaccinated with a modified-live avian
cell culture canine distemper virus vaccine licensed
for use in ferrets, an inactivated rabies vaccine
licensed for use in ferrets, or both.
Procedure—Medical records were reviewed to identify
ferrets that had an adverse event after vaccination.
Results—Adverse events developed within 25 minutes
after vaccination in 13 ferrets. One ferret developed
an adverse event after receiving a distemper
and a rabies vaccine simultaneously and developed a
second adverse event the following year after receiving
the rabies vaccine alone. Therefore, a total of 14
adverse events were identified. All adverse events
were an anaphylactic reaction characterized by generalized
hyperemia, hypersalivation, and vomiting. Ten
of the 14 anaphylactic reactions occurred after ferrets
received both vaccines, 3 occurred after ferrets
received the distemper vaccine alone, and 1 occurred
after a ferret received the rabies vaccine alone.
Incidences of adverse events after administration of
both vaccines, the distemper vaccine alone, and the
rabies vaccine alone were 5.6, 5.9, and 5.6%, respectively.
Ferrets that had an anaphylactic reaction were
significantly older at the time of vaccination than were
ferrets that did not.
Conclusions and Clinical Relevance—Results suggest
that there may be a high incidence of anaphylactic
reactions after vaccination of domestic ferrets.
Ferrets should be observed for at least 25 minutes
after vaccination, and veterinarians who vaccinate ferrets
should be prepared to treat anaphylactic reactions.
(J Am Vet Med Assoc 2003;223:663–665)
Objective—To determine the pharmacokinetics of an orally administered dose of tramadol in domestic rabbits (Oryctolagus cuniculus).
Animals—6 healthy adult sexually intact female New Zealand White rabbits.
Procedures—Physical examinations and plasma biochemical analyses were performed to ensure rabbits were healthy prior to the experiment. Rabbits were anesthetized with isoflurane, and IV catheters were placed in a medial saphenous or jugular vein for collection of blood samples. One blood sample was collected before treatment with tramadol. Rabbits were allowed to recover from anesthesia a minimum of 1 hour before treatment. Then, tramadol (11 mg/kg, PO) was administered once, and blood samples were collected at various time points up to 360 minutes after administration. Blood samples were analyzed with high-performance liquid chromatography to determine plasma concentrations of tramadol and its major metabolite (O-desmethyltramadol).
Results—No adverse effects were detected after oral administration of tramadol to rabbits. Mean ± SD half-life of tramadol after administration was 145.4 ± 81.0 minutes; mean ± SD maximum plasma concentration was 135.3 ± 89.1 ng/mL.
Conclusions and Clinical Relevance—Although the dose of tramadol required to provide analgesia in rabbits is unknown, the dose administered in the study reported here did not reach a plasma concentration of tramadol or O-desmethyltramadol that would provide sufficient analgesia in humans for clinically acceptable periods. Many factors may influence absorption of orally administered tramadol in rabbits.
Objective—To validate a novel high-sensitivity
radioimmunoassay (RIA) procedure developed to
accurately measure the relatively low serum total thyroxine
(T4) concentrations of birds and reptiles and to
establish initial reference ranges for T4 concentration
in selected species of psittacine birds and snakes.
Animals—56 healthy nonmolting adult psittacine
birds representing 6 species and 42 captive snakes
representing 4 species.
Procedure—A solid-phase RIA designed to measure
free T4 concentrations in dialysates of human serum
samples was used without dialysis to evaluate total T4
concentration in treated samples obtained from birds
and reptiles. Serum T4 binding components were
removed to allow assay of undialyzed samples. Assay
validation was assessed by determining recovery of
expected amounts of T4 in treated samples that were
serially diluted or to which T4 was added. Intra- and
interassay coefficient of variation (CV) was determined.
Results—Mean recovery of T4 added at 4 concentrations
ranged from 84.9 to 115.0% and 95.8 to 119.4%
in snakes and birds, respectively. Intra- and interassay
CV was 3.8 and 11.3%, respectively. Serum total T4
concentrations for 5 species of birds ranged from
2.02 to 7.68 nmol/L but ranged from 3.17 to 142
nmol/L for blue-fronted Amazon parrots; concentrations
ranged from 0.21 to 6.06 nmol/L for the 4
species of snakes.
Conclusions and Clinical Relevance—This new RIA
method provides a commercially available, accurate,
and sensitive method for measurement of the relatively
low serum T4 concentrations of birds and
snakes. Initial ranges for the species evaluated were
established. (Am J Vet Res 2001;62:1750–1767)
To perform a qualitative analysis of the distribution of µ- and κ-opioid receptor mRNA in the forebrain and midbrain of budgerigars (Melopsittacus undulatus).
8 brains of male budgerigars.
Custom-made RNA hybridization probes (RNAscope; Advanced Cell Diagnostics Inc) were used for fluorescent in situ hybridization (FISH) assays performed on selected fresh frozen prepared sections of brain tissue to identify µ- and κ-opioid receptor mRNA.
There was κ-opioid receptor mRNA present in the nucleus dorsomedialis posterior thalami, lateral striatum, mesopallium, tractus corticohabenularis et corticoseptalis, griseum et fibrosum, stratum griseum centrale, medial striatum, and area parahippocampalis. There was µ-opioid receptor mRNA present in the stratum griseum centrale, stratum opticum, dorsomedialis posterior thalami, area parahippocampalis, medial striatum, and nidopallium intermedium.
Consistent with previous studies in pigeons and domestic chicks, κ-opioid receptors were more abundant than µ-opioid receptors in the samples of the present study. The results of this study may also help explain the hyperexcitability or lack of response that can occur with administration of pure µ-opioid receptor agonists, but not κ-opioid receptor agonists. This study was not quantitative, so further research should endeavor to compare the various regions of the brain using FISH technology.
Objective—To evaluate the effect of IV administration of tramadol hydrochloride on the minimum alveolar concentration of isoflurane (ISOMAC) that prevented purposeful movement of rabbits in response to a noxious stimulus.
Animals—Six 6- to 12-month-old female New Zealand White rabbits.
Procedures—Anesthesia was induced and maintained with isoflurane in oxygen. A baseline ISOMAC was determined by clamping a pedal digit with sponge forceps until gross purposeful movement was detected or a period of 60 seconds elapsed. Subsequently, tramadol (4.4 mg/kg) was administered IV and the posttreatment ISOMAC (ISOMACT) was measured.
Results—Mean ± SD ISOMAC and ISOMACT values were 2.33 ± 0.13% and 2.12 ± 0.17%, respectively. The ISOMAC value decreased by 9 ± 4% after tramadol was administered. Plasma tramadol and its major metabolite (M1) concentrations at the time of ISOMACT determination varied widely (ranges, 181 to 636 ng/mL and 32 to 61 ng/mL, respectively). Intervals to determination of ISOMACT and plasma tramadol and M1 concentrations were not correlated with percentage change in the ISOMAC. Heart rate decreased significantly immediately after tramadol administration but by 10 minutes afterward was not different from the pretreatment value. Systolic arterial blood pressure decreased to approximately 60 mm Hg for approximately 5 minutes in 3 rabbits after tramadol administration. No adverse effects were detected.
Conclusions and Clinical Relevance—As administered, tramadol had a significant but clinically unimportant effect on the ISOMAC in rabbits. Higher doses of tramadol may provide clinically important reductions but may result in a greater degree of cardiovascular depression.
Objective—To describe morbidity, function, outcome, and owner satisfaction associated with limb amputation in domestic rabbits.
Design—Retrospective case series.
Animals—34 client-owned domestic rabbits.
Procedures—Medical records of domestic rabbits undergoing limb amputation for any cause between 2000 and 2009 were reviewed. The Kaplan-Meier method was used to estimate survival rate and median survival time, and variables were analyzed for relationship to risk of morbidity resulting in euthanasia and to outcome (survival vs nonsurvival [death or euthanasia]). Owners were interviewed to determine satisfaction with outcome of the procedure.
Results—28 rabbits underwent pelvic limb amputation, and 6 underwent thoracic limb amputation. At the last follow-up, 18 rabbits were dead, 9 were alive, and 7 were lost to follow-up. Median overall survival time was 720 days (range, 4 to 3,250 days). Acute and delayed or chronic complications were observed in 22 of 34 and 19 of 32 rabbits, respectively, most commonly difficulty ambulating, hygiene issues, and pododermatitis (cutaneous ulcers at the hock). Six rabbits were euthanized because of complications at a median of 104 days (range, 4 to 399 days) after surgery. Risk of morbidity resulting in euthanasia increased with heavier body weight and concurrent disease affecting ambulation at the time of amputation. Weight, age, and pododermatitis at the time of amputation were significantly negatively associated with survival time. Thirty-one (91%) owners were satisfied with the outcome.
Conclusions and Clinical Relevance—Although limb amputation was tolerated by most rabbits and most owners were satisfied, complications resulted in death in 6 of 34 (18%) rabbits, and 19 of 32 (59%) developed chronic complications. Amputation in heavy rabbits or those with concurrent pododermatitis, musculoskeletal disease, or neurologic disease should be considered carefully. Because of the small sample size and retrospective nature of this study, results should be interpreted as exploratory and hypothesis generating.