High-concentration buprenorphine exceeds target plasma concentrations for extended periods following subcutaneous administration in American flamingos (Phoenicopterus ruber).

OBJECTIVE: To determine the pharmacokinetic parameters of a high-concentration buprenorphine formulation after a single SC dose in American flamingos (Phoenicopterus ruber). ANIMALS: 6 healthy adult American flamingos (3 males and 3 females). METHODS: A single dose of high-concentration buprenorphine (1.8 mg/kg) was administered SC to all birds. Blood samples were collected at 0.25, 0.5, 1, 2, 4, 8, 12, 24, 48, 72, and 96 hours after drug administration between October 14 and October 18, 2022. Plasma buprenorphine concentrations were determined by liquid chromatography-tandem mass spectrometry and a noncompartmental analysis was used to determine pharmacokinetic parameters. RESULTS: Mean ± SD peak plasma drug concentration (Cmax) was 195.1 ± 187.4 ng/mL, the mean time to peak plasma concentration (Tmax) was 0.32 ± 0.31 hours, the mean area under the concentration-vs-time curve from time 0 to the last measured concentration (AUC0-last) was 881.4 ± 205.4 ng/mL, and mean terminal half-life (t1/2) was 12.6 ± 3.86 hours. Mean plasma buprenorphine concentrations were >1 ng/mL for at least 48 hours after drug administration. No clinically significant adverse effects were observed. CLINICAL RELEVANCE: High-concentration buprenorphine dosed at 1.8 mg/kg SC in American flamingos rapidly exceeded plasma drug concentrations reported to have analgesic effects in other avian species and maintained these levels for extended periods. Sedative effects were similar to those reported for other species. Additional studies are needed to evaluate the clinical efficacy of high-concentration buprenorphine at this dose in American flamingos.

Retrospective evaluation of wobbly hedgehog syndrome in 49 African pygmy hedgehogs (Atelerix albiventris): 2000-2020.

OBJECTIVE: To retrospectively evaluate the prevalence and clinical progression of wobbly hedgehog syndrome (WHS) and concurrent incidence of neoplasia in a cohort of African pygmy hedgehogs (Atelerix albiventris). ANIMALS: 49 hedgehogs. CLINICAL PRESENTATION AND PROCEDURES: Medical records of hedgehogs from 7 institutions across the US over a 20-year period (2000 to 2020) were retrospectively reviewed. Inclusion criteria were hedgehogs of any sex or age with postmortem CNS histopathology consistent with WHS. Collected data included sex, age at onset and euthanasia, major histopathologic findings, reported neurologic clinical signs, and treatments administered. RESULTS: 24 males and 25 females were included. Fifteen of 49 (31%) individuals had subclinical WHS with no reported antemortem neurologic clinical signs. In neurologically affected (clinical) hedgehogs (n = 34), the mean ± SD age at onset was 3.3 ± 1.5 years with a median (range) time from onset to euthanasia of 51 days (1 to 319 days). In neurologically affected hedgehogs, the most commonly reported clinical signs were ataxia (n = 21) and pelvic limb paresis (16) and the most commonly administered treatment was meloxicam (13). Overall, 31 of 49 (63%) hedgehogs had a concurrent histopathologic diagnosis of neoplasia outside of the CNS. CLINICAL RELEVANCE: The prognosis for hedgehogs with WHS is poor. No treatment had a significant effect on survival time, and neoplasia was a common comorbidity in the current cohort. A small but clinically relevant subset of neurologically normal hedgehogs had a histopathologic diagnosis of WHS.

Measurement of Cyclooxygenase Products in Plasma as Markers for Inhibition of Cyclooxygenase Isoforms by Oral Meloxicam in New Zealand White Rabbits (Oryctolagus cuniculus ).

Pain management in rabbits is a challenging task that is complicated by the rabbit's ability to hide signs of distress and the limited pharmacologic data available for this species. Pharmacokinetic data has shown that in rabbits, meloxicam, a nonsteroidal anti-inflammatory NSAID, reaches plasma concentrations that are known to provide analgesia in dogs and cats; these concentrations could theoretically alleviate pain in rabbits. However, the inhibitory effects of meloxicam on cyclooxygenase (COX) isoforms have not been studied in rabbits. In this study, we measured the products of COX-1 and COX-2 after the oral administration of a single 1 mg/kg dose of meloxicam to New Zealand White rabbits (n = 6). Blood samples were collected before drug administration (T0) and then at predetermined time points over 48 h. Plasma prostaglandin E2 (PGE2 ) and thromboxane (TxB2) concentrations were measured as surrogate markers for COX-1 and COX-2, respectively, by using commercial ELISA kits. After meloxicam administration, both TxB2 and PGE2 plasma concentrations fell significantly below baseline, with maximal mean reductions to 80% and 60% of baseline at 8 h, respectively. The reduction in PGE2 concentrations was followed by a significant increase that moved its mean plasma concentrations toward baseline between 8 and 24 h. Adverse effects such as lethargy, inappetence, or changes in fecal production were not observed in any rabbits. In conclusion, meloxicam appeared to significantly inhibit both COX-1 and COX-2 with a time course similar to previously reported meloxicam plasma concentration-time profiles in rabbits. Our data suggest that a dosage of 1 mg/kg given orally could provide analgesia to rabbits, but a more frequent dosing interval than the currently recommended daily dosing may be required to maintain clinical efficacy.

Feeding decreases the oral bioavailability of cannabidiol and cannabidiolic acid in hemp oil in New Zealand White rabbits (Oryctolagus cuniculus).

OBJECTIVE: To determine the pharmacokinetics of a solution containing cannabidiol (CBD) and cannabidiolic acid (CBDA), administered orally in 2 single-dose studies (with and without food), in the domestic rabbit (Oryctolagus cuniculus). ANIMALS: 6 healthy New Zealand White rabbits. PROCEDURES: In phase 1, 6 rabbits were administered 15 mg/kg CBD with 16.4 mg/kg CBDA orally in hemp oil. In phase 2, 6 rabbits were administered the same dose orally in hemp oil followed by a food slurry. Blood samples were collected for 24 hours to determine the pharmacokinetics of CBD and CBDA. Quantification of plasma CBD and CBDA concentrations was determined using a validated liquid chromatography-mass spectrometry (LC-MS) assay. Pharmacokinetics were determined using noncompartmental analysis. RESULTS: For CBD, the area under the curve extrapolated to infinity (AUC)0-∞ was 179.8 and 102 hours X ng/mL, the maximum plasma concentration (Cmax) was 30.4 and 15 ng/mL, the time to Cmax (tmax) was 3.78 and 3.25 hours, and the terminal half-life (t1/2λ) was 7.12 and 3.8 hours in phase 1 and phase 2, respectively. For CBDA, the AUC0-∞ was 12,286 and 6,176 hours X ng/mL, Cmax was 2,573 and 1,196 ng/mL, tmax was 1.07 and 1.12 hours, and t1/2λ was 3.26 and 3.49 hours in phase 1 and phase 2, respectively. Adverse effects were not observed in any rabbit. CLINICAL RELEVANCE: CBD and CBDA reached a greater Cmax and had a longer t1/2λ in phase 1 (without food) compared with phase 2 (with food). CBDA reached a greater Cmax but had a shorter t1/2λ than CBD both in phase 1 and phase 2. These data may be useful in determining appropriate dosing of cannabinoids in the domestic rabbit.

A three-portal laparoscopic hysterectomy in a chimpanzee (Pan troglodytes) with a uterine manipulator and vessel sealing device.

OBJECTIVE: To report the treatment and outcome of a a captive chimpanzee (Pan troglodytes) undergoing 3-portal laparoscopic hysterectomy. Additionally, the technique used for successful urinary catheterization is described. ANIMALS: A 29-year-old female intact chimpanzee with uterine bleeding. STUDY DESIGN: Clinical case report. METHODS: Uterine changes consistent with adenomyosis and/or endometriosis were noted on abdominal ultrasonographic and computed tomographic examinations. A urinary catheter was placed before a 3-portal laparoscopic hysterectomy with a uterine manipulator (VCare) and a vessel sealer (Ligasure). The uterus was submitted for histopathology. RESULTS: Preoperative urinary catheterization was achieved with several modifications and prevented bladder protrusion into the surgical field. Laparoscopy provided excellent visualization of the pelvic structures and VCare effectively maneuvered the uterus for a safe and efficient dissection. The use of the vessel sealer was effective, and bleeding was minimal. Anesthesia and surgery lasted 240 and 150 minutes, respectively. No complications were encountered. Histopathological changes of the uterus were consistent with adenomyosis and myometrial hyperplasia. The chimpanzee recovered uneventfully and returned to normal behavior with no recurrence of uterine bleeding 5 months after surgery. CONCLUSION: The 3-portal laparoscopic technique reported here allowed hysterectomy without complication in this chimpanzee. Urinary catheterization was technically challenging but successful.

Clinicopathologic findings and urolith composition for green iguanas (Iguana iguana) with urolithiasis: 21 cases and 132 stones (1996-2020).

OBJECTIVE: To document the clinical signs, diagnosis, and treatment of urolithiasis in green iguanas (Iguana iguana) and to report on the composition of uroliths from green iguanas submitted to the Minnesota Urolith Center for analysis. ANIMALS: 21 green iguanas with urolithiasis. PROCEDURES: Medical record databases of multiple veterinary teaching hospitals were searched from 1996 through 2020. Emails were sent to all facilities that submitted a urolith from a green iguana to the Minnesota Urolith Center from 1996 through 2020. Signalment; presenting complaint; physical examination findings; hematologic, biochemical, and diagnostic imaging findings; treatment; necropsy results; and survival times were described for each patient. RESULTS: Iguanas most commonly presented with nonspecific clinical signs, but 9 of the 21 iguanas had clinical signs associated with the urogenital tract. Twelve iguanas had a palpable mass in the caudal coelom. All uroliths were visible on radiographs. Surgery was performed on 15 iguanas; 3 died secondary to intra- or postoperative complications. Iguanas that underwent surgery had a median survival time of 39 months. Necropsy was performed on 5 iguanas, and urolithiasis contributed to the decision to euthanize or was the cause of death for 4. Uroliths from 132 iguanas were analyzed, and all were composed of 100% uric acid salts. CLINICAL RELEVANCE: Green iguanas with urolithiasis may not have clinical signs or physical examination findings associated with the urinary system, and hematologic and biochemical abnormalities are nonspecific. Green iguanas should be routinely examined for uroliths, and surgical treatment should be pursued.

Mortality rate of birds following intravenous administration of iodinated contrast medium for computed tomography.

OBJECTIVE: To identify potential risk factors for death following IV or intraosseous (IO) administration of contrast medium in birds undergoing CT scans. ANIMALS: 120 birds that underwent 134 contrast-enhanced CT scans. PROCEDURES: Medical records of birds of any species that underwent a CT scan which included administration of nonionic iodinated contrast medium from June 2013 to February 2020 were included. Information on birds and use of contrast medium was extracted from the medical records as well as information on deaths following IV or IO administration of contrast medium. RESULTS: 6 birds died shortly following administration of contrast medium. Necropsies were performed in 3 birds (2 cockatiels and 1 macaw), and all had lesions associated with the respiratory tract. When body weight was used as a binary variable to compare odds of death between small birds (≤ 150 g [0.33 lb]) and large birds (> 150 g), small birds had a 97-fold increased odds (OR, 97.5; 95% CI, 9.8 to 966.0) of dying following contrast medium administration. Following 131 CT scans with contrast medium administration (3 scans were excluded because of perivascular or subcutaneous leakage of contract medium), small birds had a mortality rate of 45.4% (5/11), compared with a mortality rate of 0.8% (1/120) for large (> 150 g) birds. Other variables (ie, sex, age, anesthesia or sedation, sedation protocol, and type of contrast medium) were not significantly associated with death after contrast medium administration. CONCLUSIONS AND CLINICAL RELEVANCE: Although the administration of contrast medium cannot be conclusively confirmed as the cause of death in these birds, the high mortality rate for small birds coupled with the temporality of the event following contrast medium administration justifies the cautious use of contrast medium in small sick psittacine birds.

The plasma lipidome of the Quaker parrot (Myiopsitta monachus).

Dyslipidemias and lipid-accumulation disorders are common in captive parrots, in particular in Quaker parrots. Currently available diagnostic tests only measure a fraction of blood lipids and have overall problematic cross-species applicability. Comprehensively analyzing lipids in the plasma of parrots is the first step to better understand their lipid metabolism in health and disease, as well as to explore new lipid biomarkers. The plasma lipidome of 12 Quaker parrots was investigated using UHPLC-MS/MS with both targeted and untargeted methods. Targeted methods on 6 replicates measured 432 lipids comprised of sterol, cholesterol ester, bile acid, fatty acid, acylcarnitine, glycerolipid, glycerophospholipid, and sphingolipid panels. For untargeted lipidomics, precursor ion mass-to-charge ratios were matched to corresponding lipids using the LIPIDMAPS structure database and LipidBlast at the sum composition or acyl species level of information. Sterol lipids and glycerophospholipids constituted the majority of plasma lipids on a molar basis. The most common lipids detected with the targeted methods included free cholesterol, CE(18:2), CE(20:4) for sterol lipids; PC(36:2), PC(34:2), PC(34:1) for glycerophospholipids; TG(52:3), TG(54:4), TG(54:5), TG(52:2) for glycerolipids; SM(d18:1/16:0) for sphingolipids; and palmitic acid for fatty acyls. Over a thousand different lipid species were detected by untargeted lipidomics. Sex differences in the plasma lipidome were observed using heatmaps, principal component analysis, and discriminant analysis. This report presents the first comprehensive database of plasma lipid species in psittacine birds and paves the way for further research into blood lipid diagnostics and the impact of diet, diseases, and drugs on the parrot plasma lipidome.

OUTBREAK AND TREATMENT OF CARP EDEMA VIRUS IN KOI ( CYPRINUS CARPIO) FROM NORTHERN CALIFORNIA.

Carp edema virus (CEV) is the causative agent of carp edema virus disease (CEVD), also referred to as koi sleepy disease, which is an emerging disease of global concern that may cause high rates of morbidity and mortality in common carp and ornamental koi ( Cyprinus carpio). This article reports the third confirmed outbreak of CEVD in California. In June 2015, three koi presented with clinical signs of cutaneous lesions, severe lethargy, and signs of hypoxia. All fish tested positive for CEV by polymerase chain reaction (PCR). Euthanasia and complete necropsy were performed on two fish. The most significant necropsy findings included necrotizing branchitis with marked interstitial edema, multifocal cutaneous ulcerations, and severe cutaneous edema. Treatment of the pond with 0.3-0.5% salt was recommended to the owner. Approximately 7 wk later, a recheck visit was made to the pond. No mortalities had been noted since the initiation of the salt treatment. Physical examination revealed a vast improvement but not complete elimination of the clinical signs of hypoxia and intermittent lethargy in the affected fish. Gill biopsy samples from the two most affected fish were tested and remained PCR positive for CEV. Subsequent recheck visits over 11 mo postdiagnosis and initiation of treatment showed continued improvement in most fish. Gill samples from all fish in the pond ( n = 9) were repeatedly tested by quantitative PCR for CEV, and all samples were negative. This case series further confirms the global spread of CEV and the need for practitioners to be vigilant for outbreaks of this disease. If CEVD is suspected, treatment with 0.3-0.5% salt can be recommended to potentially mitigate the effects of this disease. However, fish may remain potential carriers of this pathogen, and strict biosecurity measures should continue to be enforced for any pond that has had a confirmed CEV outbreak.

Reference Intervals for Plasma Biochemical Variables by Point-of-Care Testing in Captive Black-tailed Prairie Dogs (Cynomys ludovicianus).

Black-tailed prairie dogs (Cynomys ludovicianus) are kept in zoological collections, maintained as companion pets, and aretested in field and laboratory settings. Biochemical analysis for routine health and research purposes can be performed byusing point-of-care (POC) testing; however, analyzer- and species-specific reference intervals need to be determined. In this prospective study, 50 captive-raised sexually intact prairie dogs (16 females, 34 males) underwent plasma biochemical analysisby using a veterinary POC biochemical analyzer. We used a manufacturer-predetermined profile of 14 analytes: albumin, ALP,ALT, amylase, BUN, calcium, creatinine, glucose, potassium, sodium, phosphorus, total bilirubin, total protein and globulin.A subset of 17 samples was tested concurrently for the same 14 analytes by using a reference laboratory analyzer, and wedetermined RI for the POC analyzer for these 14 biochemical analytes. Sex had a significant effect on albumin and creatininevalues, which were higher in females than males, and on ALT, which was lower in females. In addition, age had an effect on9 plasma analytes: juvenile animals had higher plasma concentrations of albumin, ALP, ALT, BUN, and glucose than adultanimals, whereas adults had higher concentrations of creatinine, sodium, total protein, and globulins. Only calcium and BUNhad acceptable analytical agreement between the POC and reference analyzers. The reference intervals determined in this study can aid clinicians and researchers performing POC plasma biochemical analysis in prairie dogs, providing that they consider potential analyzer-, sex-, and age-related effects.

Influence of Isoflurane Anesthesia on Plasma Thyroxine Concentrations in Black-tailed Prairie Dogs (Cynomys ludovicianus).

Anesthesia can affect measured thyroxine (total T4) concentrations in humans and animals, but its effect in black-tailed prairie dogs (Cynomys ludovicianus) has not yet been studied. We used isoflurane to anesthetize 12 prairie dogs for 60 min. Blood samples were obtained from each animal immediately after anesthesia induction and at 30 and 60 min and used for analysis of plasma T4 concentration. The plasma T4 concentration (mean ± 1 SD) was significantly decreased from baseline (3.49 ± 0.52 µg/dL) at both 30 min (3.24 ± 0.52 µg/dL) and 60 min (3.27 ± 0.65 µg/dL) after induction. Compared with baseline, some of the T4 trends were inconsistent between animals, and individual variability in response was responsible for 86% of the overall variability. Regardless of the observed change under isoflurane anesthesia, all measurements in all prairie dogs and at all time points (2.4 to 4.4 µg/dL) were within the reported normal plasma T4 reference range for this species. In conclusion, isoflurane anesthesia appears to cause a significant but inconsistent reduction in plasma T4 concentrations in black-tailed prairie dogs, but because values remain within normal basal levels, the clinical importance of this effect is likely minimal.

Partial gastrectomy for resection of a gastric leiomyoma in a guinea pig (Cavia porcellus).

CASE DESCRIPTION A 4-year-old sexually intact male pet guinea pig (Cavia porcellus) was evaluated for a routine wellness examination. CLINICAL FINDINGS During physical examination, a small mass was palpated in the cranial aspect of the abdomen. Abdominal radiographic and ultrasonographic findings were suggestive of a gastric mass. Cytologic evaluation of a fine-needle aspirate of the mass was indicative of spindle cell proliferation most consistent with a sarcoma. TREATMENT AND OUTCOME The patient was anesthetized, and an exploratory laparotomy and partial gastrectomy were performed to resect the gastric mass. Histologic and immunohistochemical examinations of the mass revealed that it was a gastric leiomyoma. The patient recovered from surgery without complications. No evidence of mass recurrence was observed during an abdominal ultrasonographic examination performed approximately 19 months after surgery. CLINICAL RELEVANCE To our knowledge, this was the first report of the clinical diagnosis and successful surgical treatment of a gastric neoplasm in a guinea pig. Gastric leiomyomas are not uncommon in guinea pigs, and although benign, they can cause clinical signs if they become large enough to impair gastric function. Gastrointestinal surgery should be considered as a treatment option for guinea pigs with similar gastric neoplasms.

Venous blood gas analytes during isoflurane anesthesia in black-tailed prairie dogs (Cynomys ludovicianus).

OBJECTIVE: To describe changes in venous blood gas analytes during isoflurane anesthesia in black-tailed prairie dogs (Cynomys ludovicianus). DESIGN: Prospective study. ANIMALS: 16 black-tailed prairie dogs. PROCEDURES: Black-tailed prairie dogs were placed in an anesthesia chamber for induction of general anesthesia, which was maintained with isoflurane in oxygen delivered via mask. Immediately following anesthetic induction, a venous blood sample was obtained from the medial saphenous vein; a second venous blood sample was obtained just prior to anesthetic gas shutoff. An evaluation of venous blood gas analytes was performed on each sample. General linear mixed models with repeated measures were used for data analyses. RESULTS: Median anesthetic time was 90 minutes (range, 60 to 111 minutes). A significant increase from immediately after induction to completion of anesthesia was observed in Pco2 and mean blood chloride ion, BUN, and creatinine concentrations. A decrease in Po2, mean blood pH, and anion gap was observed from induction of anesthesia to completion. No significant differences during anesthesia were observed in mean base excess or blood bicarbonate, sodium, potassium, calcium, magnesium, blood glucose, lactate, and total CO2 concentrations. No complications occurred during or after anesthesia for any animal. CONCLUSIONS AND CLINICAL RELEVANCE: Examination of prairie dogs often requires general anesthesia, with isoflurane currently the inhalation agent of choice. Results suggested respiratory acidosis and relative azotemia may occur during isoflurane anesthesia of prairie dogs. Given the increased risk associated with anesthesia in small mammals and the propensity for respiratory disease in prairie dogs, insight into physiologic changes associated with isoflurane anesthesia in healthy prairie dogs can aid in perioperative evaluation and anesthetic monitoring in this rodent species.