OBJECTIVE To evaluate the effects of restraint time and thermometer insertion depth on rectal temperature measurements in chinchillas and determine the extent of agreement between temperatures measured with 2 tympanic and a rectal thermometer.
DESIGN Prospective method comparison study.
ANIMALS 47 healthy chinchillas.
PROCEDURES Effects of 1- and 2-cm rectal thermometer insertion depths and the effect of manual restraint for up to 5 minutes were evaluated. Near simultaneous temperature measurements were obtained with a human tympanic, a veterinary tympanic, and a rectal thermometer by 2 observers. Duplicate temperature measurements were obtained for each method, and the sequence of measurements was randomized for each animal.
RESULTS Rectal temperature readings obtained at a depth of 2 cm were significantly higher (mean ± SD, 1.14 ± 0.77°C [2.05° ± 1.39°F]) than those obtained at 1 cm. After 3 minutes, manual restraint had a significant effect on rectal temperature. The reference interval for rectal temperature in chinchillas with a 2-cm thermometer insertion depth was calculated as 34.9° to 37.9°C (94.8° to 100.2°F). Both tympanic infrared thermometers had significant systematic bias (0.42 ± 0.12°C [0.76° ± 0.22°F]) and proportional bias (0.88 ± 0.14°C [1.58° ± 0.25°F]). The coefficients of reliability for the rectal thermometer, the human tympanic thermometer, and the veterinary tympanic thermometer were 0.86, 0.85, and 0.69, respectively.
CONCLUSIONS AND CLINICAL RELEVANCE Rectal thermometer insertion depth and duration of manual restraint had a significant effect on rectal temperature measurements in chinchillas. Because of significant systematic and proportional bias, tympanic thermometry was not considered a suitable replacement for rectal thermometry in chinchillas.
To determine epidemiological features of cardiovascular disease in rabbits examined at a veterinary teaching hospital and characterize clinical and pathological findings.
Medical records from 2001 to 2018 were reviewed, and data were collected. Echocardiographic images and histologic diagnoses were reviewed.
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.
To determine the pharmacokinetics and adverse effects of maropitant citrate after IV and SC administration to New Zealand White rabbits (Oryctolagus cuniculus).
11 sexually intact (3 males and 8 females) adult rabbits.
Each rabbit received maropitant citrate (1 mg/kg) IV or SC. Blood samples were collected at 9 (SC) or 10 (IV) time points over 48 hours. After a 2-week washout period, rabbits received maropitant by the alternate administration route. Pharmacokinetic parameters were calculated. Body weight, food and water consumption, injection site, mentation, and urine and fecal output were monitored.
Mean ± SD maximum concentration after SC administration was 14.4 ± 10.9 ng/mL and was detected at 1.25 ± 0.89 hours. Terminal half-life after IV and SC administration was 10.4 ± 1.6 hours and 13.1 ± 2.44 hours, respectively. Bioavailability after SC administration was 58.9 ± 13.3%. Plasma concentration at 24 hours was 2.87 ± 1.69 ng/mL after IV administration and 3.4 ± 1.2 ng/mL after SC administration. Four rabbits developed local dermal reactions at the injection site after SC injection. Increased fecal production was detected on the day of treatment and 1 day after treatment.
CONCLUSIONS AND CLINICAL RELEVANCE
Plasma concentrations of rabbits 24 hours after SC and IV administration of maropitant citrate (1 mg/kg) were similar to those of dogs at 24 hours. Reactions at the SC injection site were the most common adverse effect detected. Increased fecal output may suggest an effect on gastrointestinal motility. Additional pharmacodynamic and multidose studies are needed.
To determine the pharmacokinetics and potential adverse effects of pimobendan after oral administration in New Zealand White rabbits (Ocytolagus cuniculi).
10 adult sexually intact (5 males and 5 females) rabbits.
2 pilot studies were performed with a pimobendan suspension or oral tablets. Eight rabbits received 7.5 mg of pimobendan (mean 2.08 mg/kg) suspended in a critical care feeding formula. Plasma concentrations of pimobendan and O-demethylpimobendan (ODMP) were measured, and pharmacokinetic parameters were calculated for pimobendan by noncompartmental analysis. Body weight, food and water consumption, mentation, urine, and fecal output were monitored.
Mean ± SD maximum concentration following pimobendan administration was 15.7 ± 7.54 ng/mL and was detected at 2.79 ± 1.25 hours. The half-life was 3.54 ± 1.32 hours. Plasma concentrations of pimobendan were detectable for up to 24 hours. The active metabolite, ODMP, was detected in rabbits for 24 to 36 hours. An adverse event occurred following administration of pimobendan in tablet form in 1 pilot study, resulting in death secondary to aspiration. No other adverse events occurred.
Plasma concentrations of pimobendan were lower than previously reported for dogs and cats, despite administration of higher doses, and had longer time to maximum concentration and half-life. Based on this study, 2 mg/kg of pimobendan in a critical care feeding formulation should maintain above a target plasma concentration for 12 to 24 hours. However, further studies evaluating multiple-dose administration as well as pharmacodynamic studies and clinical trials in rabbits with congestive heart failure are needed to determine accurate dose and frequency recommendations.
To document clinicopathologic findings in domestic rabbits with liver lobe torsion and identify prognostic factors.
Medical records of 4 institutions were reviewed to identify rabbits with an antemortem diagnosis of liver lobe torsion that were examined between 2010 and 2020.
The prevalence of liver lobe torsion was 0.7% (82/11,402). In all 82 rabbits, the diagnosis was made by means of abdominal ultrasonography. Fifty (60.1%) rabbits underwent liver lobectomy, 23 (28%) received medical treatment alone, and 9 (10.9%) were euthanized or died on presentation. Overall, 32 (39%) rabbits died within 7 days of initial presentation and 50 (61%) survived. Seven-day survival rate did not differ significantly between medical treatment alone and surgical treatment. However, median survival time following medical treatment (530 days) was shorter than that following surgical treatment (1,452 days). Six of 14 rabbits had evidence of systemic inflammatory disease on necropsy. Rabbits with right liver lobe torsion were less likely to survive for 7 days than were those with caudate torsions (P = 0.046; OR, 3.27; 95% CI, 1.04 to 11.3). Rabbits with moderate to severe anemia were less likely to survive for 7 days than were rabbits that were not anemic or had mild anemia (P = 0.006; OR, 4.41; 95% CI, 1.55 to 12.51). Other factors associated with a decreased 7-day survival rate were high heart rate at admission (P = 0.013) and additional days without defecation after admission (P < 0.001). Use of tramadol was associated with an increased survival rate (P = 0.018).
The prognosis for rabbits with liver lobe torsions was more guarded than previously described. Rabbits that underwent liver lobectomy had a longer median survival time than did rabbits that only received medical treatment.