CLINICAL AND PATHOLOGIC FINDINGS IN IGUANIDS WITH SODIUM URATE CHOLELITHIASIS.

Four green iguanas (Iguana iguana) and one blue iguana (Cyclura lewisi) from five facilities were diagnosed with sodium urate cholelithiasis. One case was diagnosed antemortem via ultrasonography, and the iguana underwent a choledochotomy for treatment. The other four cases were identified at necropsy. Pathologic hepatic and biliary changes were present in four of the five cases at necropsy. Histologically, four iguanas had hepatic fibrosis, three had bile duct hyperplasia, and one had cholangiohepatitis and pancreaticocholedochitis. Two iguanas had pathologic renal changes. This is the first report of sodium urate cholelithiasis in reptiles. This case series highlights the potential significant clinical disease caused by sodium urate cholelithiasis and the importance of biliary system evaluation. Further investigation is recommended to explore the pathogenesis of reptilian sodium urate cholelith formation.

Carrageenan-induced inflammation elicits behavioral changes in cockatiels (Nymphicus hollandicus) for potential pain scale development.

OBJECTIVE: To evaluate behaviors associated with inflammatory pain induced by carrageenan injection in the cockatiel and determine interobserver agreement. ANIMALS: 16 adult cockatiels. METHODS: Cockatiels were randomly assigned as either treatment (carrageenan injection) or control (sham injection) group. The treatment group received a subcutaneous injection of 0.05 mL of a 1% lambda carrageenan solution into the left footpad. Following treatment or control procedures, all cockatiels were video recorded individually for 9.5 hours. Ten minutes of video at each of 11 time points postinjection and/or handling were evaluated by 3 different observers. Twenty-five behaviors within 6 categories (resting, locomotion, maintenance, intake, interaction with environment, and limb and body posture) were assessed, in addition to crest position and mentation. Differences in individual behaviors tallies were assessed using serial Wilcoxon sum rank tests. Interobserver agreement was assessed using an intraclass correlation coefficient for a 2-way design for consistency among multiple observers. RESULTS: Treatment cockatiels exhibited significantly increased focal preening (q = .023) and increased burst preening (q = .036), while control cockatiels spent significantly more time in an upright stance (q = .036). Although the remainder of behaviors observed were not statistically significant between groups, additional variables of interest seen more frequently in treatment cockatiels included non-weight-bearing stance, holding of the body low, and being nonvigilant. The level of agreement between observers was variable based on the specific behaviors; nevertheless, the dynamic behaviors were substantial to strong. CLINICAL RELEVANCE: Carrageenan-induced inflammation-associated behaviors may be valuable in developing a pain scale and evaluating mild inflammatory pain in small psittacine species.

Grey parrot (Psittacus erithacus) beak papillae and nerves identified using novel 2-D and 3-D imaging modalities.

OBJECTIVE: The avian beak is a complex organ containing bone, neurovascular tissue, and keratinized covering (rhamphotheca). Nerve-rich papillae extend through bone into rhamphotheca providing sensory input from the beak tip. Beak trimming is a common procedure in avian species and is used for corrective, cosmetic, and behavioral modification purposes. Yet, practitioners are not well versed in complete beak anatomy, and therefore, beak trimming often disregards neurovasculature, injuring the patient and hampering recovery. Here, using comprehensive anatomical description, we aim to provide recommendations on how to safely perform beak trimming without damaging underlying sensory papillae. ANIMALS: Here, we evaluated beaks of 2 deceased grey parrots (Psittacus erithacus). PROCEDURES: In one, we used a novel stain and microcomputed tomography to visualize papillae in the upper and lower beaks. In a second, we hand isolated the upper and lower beak dermal papillae and used high-resolution photography plus traditional paraffin histology. RESULTS: Papillae and their nerves were easily identified in these 2- and 3-dimensional approaches. This allowed us to determine the approximate lengths of papillae within the upper and lower beak. CLINICAL RELEVANCE: Based on these findings, the authors recommend lateral radiographs of the bird's head and beak to identify the location of the underlying bone relative to the overlying rhamphotheca before performing beak trims. Specifically in grey parrots, the authors recommend the upper and lower beak should not be trimmed closer than 8 to 10 mm from the underlying bone. Further work is needed to support these recommendations and provide guidelines for other species.

Pharmacokinetics of butorphanol tartrate in a poloxamer P407 gel formulation administered to orange-winged Amazon parrots (Amazona amazonica).

OBJECTIVES: To determine the pharmacokinetics of butorphanol tartrate incorporated into poloxamer 407 (P407) after subcutaneous administration to orange-winged Amazon parrots (Amazona amazonica). ANIMALS: Six orange-winged Amazon parrots, ages 28 to 45 years. PROCEDURES: A sterile formulation of butorphanol in P407 (But-P407) as a 25% gel was created to produce a concentration of 8.3 mg/mL. The formulation was administered SC at a dose of 12.5 mg/kg to all birds. Blood samples were collected at baseline prior to injection (time 0) and then at 0.08, 0.5, 1, 1.5, 4, 8, and 12 hours after drug administration. Butorphanol concentrations were quantitated via liquid chromatography-tandem mass spectrometry. Pharmacokinetic analysis was performed using noncompartmental analysis and a commercially available software program. RESULTS: Plasma concentrations of butorphanol remained > 100 ng/mL for > 4 hours for some birds (3/5) but were < 100 ng/mL for all birds by the 8-hour mark. Cmax and tmax were 346.9 ± 233.7 ng/mL and 1.3 ± 0.274 hours, respectively. Half-life was 1.56 ± 0.445 hours. No adverse effects were detected. CLINICAL RELEVANCE: Butorphanol was absorbed from the But-P407 25% by the majority of the orange-winged Amazon parrots in this study (3/5), although to a lesser extent compared to Hispaniolan Amazon parrots. Absorption followed a pharmacokinetic profile compatible with a sustained-release drug. A dose of 12.5 mg/kg, SC, would be expected to provide antinociception for 4 to 8 hours, although pharmacodynamic studies in this species using this formulation have not demonstrated this.

Absorption of grapiprant in red-tailed hawks (Buteo jamaicensis) is decreased when administered with food.

OBJECTIVE: Describe the pharmacokinetics of grapiprant administered orally with food to red-tailed hawks (RTHAs; Buteo jamaicensis) and compare the results with previously described grapiprant pharmacokinetics administered without food in this species. ANIMALS: 6 healthy adult RTHA (3 males, 3 females) under human care. PROCEDURES: A single dose of grapiprant (30 mg/kg) was given orally to RTHAs, followed by force-feeding. Blood samples were obtained at 14 time points for 120 hours postgrapiprant administration. Plasma concentrations of grapiprant were measured via tandem liquid chromatography-mass spectrometry. Nonparametric superimposition using pharmacokinetic modeling software used plasma concentrations to calculate simulations of grapiprant plasma concentrations for 30 mg/kg administered orally with food every 12 hours. RESULTS: The arithmetic mean maximum plasma concentration was 405.8 ng/mL, time to maximum plasma concentration was 16 hours, and harmonic mean terminal half-life was 15.6 hours. Simulations determined 30 mg/kg every 12 hours could attain minimum effective concentrations (> 164 ng/mL) reported in dogs for a sustained period of approximately 20 hours. CLINICAL RELEVANCE: Grapiprant plasma concentrations were achieved above the canine therapeutic concentrations within 16 hours postmedication. Mean concentrations were maintained for approximately 20 hours. Simulations support a dosing frequency of 12-hour intervals with food reaching minimum effective concentrations established for canines, although it is unknown whether these plasma concentrations are therapeutic for birds. Bioaccumulation was not noted on simulations secondary to increased grapiprant administration. Further research including multidose assessments at this current dose with food, in vitro pharmacological characterization, and pharmacodynamic studies in this species are warranted.

Pharmacokinetics of grapiprant administered to red-tailed hawks (Buteo jamaicensis) after food was withheld for 24 hours.

OBJECTIVE: To identify an oral dose of grapiprant for red-tailed hawks (RTHAs; Buteo jamaicensis) that would achieve a plasma concentration > 164 ng/mL, which is considered therapeutic for dogs with osteoarthritis. ANIMALS: 6 healthy adult RTHAs. PROCEDURES: A preliminary study, in which grapiprant (4 mg/kg [n = 2], 11 mg/kg [2], or 45 mg/kg [2]) was delivered into the crop of RTHAs from which food had been withheld for 24 hours, was performed to obtained pharmacokinetic data for use with modeling software to simulate results for grapiprant doses of 20, 25, 30, 35, and 40 mg/kg. Simulation results directed our selection of the grapiprant dose administered to the RTHAs in a single-dose study. Plasma grapiprant concentration, body weight, and gastrointestinal signs of RTHAs were monitored. RESULTS: On the basis of results from the preliminary study and simulations, a grapiprant dose of 30 mg/kg was used in the single-dose study. The geometric mean maximum observed plasma concentration of grapiprant was 3,184 ng/mL, time to maximum plasma grapiprant concentration was 2.0 hours, and the harmonic mean terminal half-life was 17.1 hours. No substantial adverse effects were observed. CONCLUSIONS AND CLINICAL RELEVANCE: Although the single dose of grapiprant (30 mg/kg) delivered into the crop achieved plasma concentrations > 164 ng/mL in the RTHAs, it was unknown whether this concentration would be therapeutic for birds. Further research that incorporates multidose assessments, safety monitoring, and pharmacodynamic data collection is warranted on the use of grapiprant in RTHAs from which food was withheld versus not withheld.

Varying Expression of Mu and Kappa Opioid Receptors in Cockatiels (Nymphicus hollandicus) and Domestic Pigeons (Columba livia domestica).

Avian species have varying analgesic responses to opioid drugs. Some of this variability could be due to extrinsic factors such as administration route or dose. However, intrinsic factors such as gene expression or polymorphic differences in opioid receptors may be important components. OBJECTIVES: The objectives of this study were to determine the relative gene expression and polymorphisms present for mu and kappa opioid receptors (OPRM1 and OPRK1) in the cerebrum, brainstem, spinal cord, and footpad of cockatiels and pigeons. METHODS: Tissue biopsies were obtained from 11 adult cockatiels (6 male and 5 female) and 11 adult pigeons (6 male and 5 female). RNA was extracted and qPCR was performed to determine the level of gene expression for OPRM1 and OPRK1 relative to a reference gene phosphoglycerate kinase 1 (PGK1) using the ΔΔCt method. Sanger sequencing was performed to identify polymorphisms, if present. RESULTS: There were higher expression levels of OPRM1 compared to OPRK1 in all tissues examined regardless of species (p < 0.001, FDR p < 0.001) Cockatiels had less OPRK1 expression in the cerebrum compared to pigeons (p = 0.005, FDR p = 0.004). Cockatiels had more OPRM1 expression in the brainstem (p = 0.045, FDR p = 0.029), but less OPRM1 expression in the footpad compared to pigeons (p = 0.029, FDR p = 0.021). No other significant differences in OPRM1 or OPRK1 expression were identified across species. Two missense polymorphisms were identified in OPRK1; none were found in OPRM1. CONCLUSION: The differential expression of opioid receptors between cockatiels and pigeons could have implications for variability in analgesic response between these two species.

Pharmacokinetics of hydromorphone hydrochloride after intramuscular and intravenous administration of a single dose to orange-winged Amazon parrots (Amazona amazonica).

OBJECTIVE: To evaluate the pharmacokinetics of hydromorphone hydrochloride after IM and IV administration to orange-winged Amazon parrots (Amazona amazonica). ANIMALS: 8 orange-winged Amazon parrots (4 males and 4 females). PROCEDURES: Hydromorphone (1 mg/kg) was administered once IM. Blood samples were collected 5 minutes and 0.5, 1.5, 2, 3, 6, and 9 hours after drug administration. Plasma hydromorphone concentrations were determined with liquid chromatography-tandem mass spectrometry, and pharmacokinetic parameters were calculated with a compartmental model. The experiment was repeated 1 month later with the same dose of hydromorphone administered IV. RESULTS: Plasma hydromorphone concentrations were > 1 ng/mL for 6 hours in 8 of 8 and 6 of 7 parrots after IM and IV injection, respectively. After IM administration, mean bioavailability was 97.6%, and mean maximum plasma concentration was 179.1 ng/mL 17 minutes after injection. Mean volume of distribution and plasma drug clearance were 4.24 L/kg and 64.2 mL/min/kg, respectively, after IV administration. Mean elimination half-lives were 1.74 and 1.45 hours after IM and IV administration, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: Hydromorphone hydrochloride had high bioavailability and rapid elimination after IM administration, with rapid plasma clearance and a large volume of distribution after IV administration in orange-winged Amazon parrots. Drug elimination half-lives were short. Further pharmacokinetic studies of hydromorphone and its metabolites, including investigation of multiple doses, different routes of administration, and sustained-release formulations, are recommended.

Evaluation of the thermal antinociceptive effects of hydromorphone hydrochloride after intramuscular administration to orange-winged Amazon parrots (Amazona amazonica).

OBJECTIVE: To evaluate the thermal antinociceptive effects of hydromorphone hydrochloride after IM administration to orange-winged Amazon parrots (Amazona amazonica). ANIMALS: 8 healthy adult parrots (4 males and 4 females). PROCEDURES: In a randomized crossover study, each bird received hydromorphone (0.1, 1, and 2 mg/kg) and saline (0.9% NaCl) solution (1 mL/kg; control) IM, with a 7-day interval between treatments. Each bird was assigned an agitation-sedation score, and the thermal foot withdrawal threshold (TFWT) was measured at predetermined times before and after treatment administration. Adverse effects were also monitored. The TFWT, agitation-sedation score, and proportion of birds that developed adverse effects were compared among treatments over time. RESULTS: Compared with the mean TFWT for the control treatment, the mean TFWT was significantly increased at 0.5, 1.5, and 3 hours and 1.5, 3, and 6 hours after administration of the 1- and 2-mg/kg hydromorphone doses, respectively. Significant agitation was observed at 0.5, 1.5, and 3 hours after administration of the 1 - and 2-mg/kg hydromorphone doses. Other adverse effects observed after administration of the 1- and 2-mg/kg doses included miosis, ataxia, and nausea-like behavior (opening the beak and moving the tongue back and forth). CONCLUSIONS AND CLINICAL RELEVANCE: Although the 1- and 2-mg/kg hydromorphone doses appeared to have antinociceptive effects, they also caused agitation, signs of nausea, and ataxia. Further research is necessary to evaluate administration of lower doses of hydromorphone and other types of stimulation to better elucidate the analgesic and adverse effects of the drug in psittacine species.

Pharmacokinetics of amantadine after oral administration of single and multiple doses to orange-winged Amazon parrots (Amazona amazonica).

OBJECTIVE: To determine the pharmacokinetics of amantadine after oral administration of single and multiple doses to orange-winged Amazon parrots (Amazona amazonica). ANIMALS: 12 adult orange-winged Amazon parrots (6 males and 6 females). PROCEDURES: A single dose of amantadine was orally administered to 6 birds at 5 mg/kg (n = 2), 10 mg/kg (2), and 20 mg/kg (2) in a preliminary trial. On the basis of the results, a single dose of amantadine (10 mg/kg, PO) was administered to 6 other birds. Two months later, multiple doses of amantadine (5 mg/kg, PO, q 24 h for 7 days) were administered to 8 birds. Heart rate, respiratory rate, behavior, and urofeces were monitored. Plasma concentrations of amantadine were measured via tandem liquid chromatography-mass spectrometry. Pharmacokinetic parameter estimates were determined via noncompartmental analysis. RESULTS: Mean ± SD maximum plasma concentration, time to maximum plasma concentration, half-life, and area under the concentration-versus-time curve from the last dose to infinity were 1,174 ± 186 ng/mL, 3.8 ± 1.8 hours, 23.2 ± 2.9 hours, and 38.6 ± 7.4 µg·h/mL, respectively, after a single dose and 1,185 ± 270 ng/mL, 3.0 ± 2.4 hours, 21.5 ± 5.3 hours, and 26.3 ± 5.7 µg·h/mL, respectively, at steady state after multiple doses. No adverse effects were observed. CONCLUSIONS AND CLINICAL RELEVANCE: Once-daily oral administration of amantadine at 5 mg/kg to orange-winged Amazon parrots maintained plasma concentrations above those considered to be therapeutic in dogs. Further studies evaluating safety and efficacy of amantadine in orange-winged Amazon parrots are warranted.

Pilot Study: Correlation of the Surface Skin Temperature Between the Leg and Foot Using Thermographic Imaging in Captive Hawks.

The purpose of this study was to determine whether the thermal image temperatures of the tibiotarsal scaled region of the raptor leg and the plantar surface of ipsilateral foot while perching were correlated. The correlation between leg and foot temperature was sought to determine whether remote imaging of the legs can be used as a reliable predictor of foot temperature. The right and left tarsometatarsal region (Leg) and metatarsal pad (Foot) of 10 captive hawks, including 8 red-tailed hawks (Buteo jamaicensis), 1 Harris's hawk (Parabuteo unicinctus), and 1 Swainson's hawk (Buteo swainsoni) were imaged once daily over 3 consecutive days. To account for conditions of the metatarsal pad that might affect the thermal image, 3 groups were identified: Normal, Active when mild hyperemia was present, and Suspect when abrasions were noted. A significant correlation was evident when thermography readings of the tarsometatarsal region (R.Leg and L.Leg) of the unrestrained bird were compared with readings from the plantar surface of the ipsilateral metatarsal pad when restrained (R.Foot and L.Foot). The correlations for R.Leg versus R.Foot (r = 0.81) and L.Leg versus L.Foot (r = 0.74) suggest that temperatures of the tarsometatarsal region of perching hawks measured by infrared thermography may be useful to screen and monitor for the presence of thermal changes associated with inflammation of the metatarsal pad in captive hawk species.

Evaluation of Orally Administered Atorvastatin on Plasma Lipid and Biochemistry Profiles in Hypercholesterolemic Hispaniolan Amazon Parrots (Amazona ventralis).

Atorvastatin is a synthetic statin administered in its active form and used for the treatment of dyslipidemias. In the current study, the effects of atorvastatin were evaluated on plasma lipid profiles and the potential for adverse effects after once daily PO dosing of atorvastatin for 30 days in Hispaniolan Amazon parrots (Amazona ventralis). Sixteen adult parrots (10 female, 6 male) with hypercholesterolemia were used for this study. Birds were assigned to 2 groups (treatment and control) of 8 parrots each (3 male, 5 female) after balancing for age, sex, originating institution, and baseline plasma cholesterol values. Compounded atorvastatin oral suspension (10 mg/kg) was administered PO once daily via gavage into the crop. Equivalent volumes of placebo suspension were administered to the control group. Plasma biochemistry and plasma lipid profile analysis (total cholesterol, high-density lipoprotein cholesterol [HDL-C], low-density lipoprotein cholesterol [LDL-C], and triglycerides [TGs]) were analyzed on days 0, 14, and 30. Plasma samples and HDL-C fractions were evaluated for cholesterol and TG concentrations via enzymatic assays. Subtraction of HDL-C values from total cholesterol yielded the non-HDL-C concentration for each bird. Birds were routinely assessed for appetite, activity, and urofeces. Plasma atorvastatin concentrations were obtained from 7 of 8 birds in the treatment group from banked samples. Those samples were obtained on days 14 and 30, with drug administration 6 to 8 hours before collection. No significant differences were observed in total cholesterol, HDL-C, non-HDL-C, or TG between treatment and control groups at days 0, 14, and 30. Plasma atorvastatin concentrations were variable on day 14 (0.54-5.41 ng/ mL for 6 of 7 samples, with 1 outlier of 307 ng/mL) and on day 30 (0.79-6.74 ng/mL). No adverse effects were noted in any of the birds during the study period. When dosed PO at 10 mg/kg once daily, atorvastatin did not result in significant changes to plasma lipid profiles (eg, lowering of plasma total or non-HDL-C concentrations) at any time point during this study. Future studies to investigate pharmacokinetic and pharmacodynamic properties of atorvastatin in parrots may require increased doses and/or frequency of administration.

Modified Tail Amputation Technique in a Blue and Gold Macaw (Ara ararauna) With Uropygial Gland Adenocarcinoma.

A 33-year-old male blue and gold macaw (Ara ararauna) presented with a 5-month history of an ulcerated lesion and feather loss at the tail base. Two 4-mm biopsies obtained by the primary care veterinarian were consistent with uropygial gland adenocarcinoma. The bird was examined at the Veterinary Medical Teaching Hospital, University of California, and on physical evaluation, the dorsal and ventral surface of the tail base were devoid of feathers, ulcerated and crusted without an identifiable uropygial gland. Complete blood count, plasma biochemistry panel, whole-body radiographs, and an echocardiogram were performed before surgery. The bird was anesthetized, and a complete amputation of the tail was performed. The skin was incised with a radiofrequency electrosurgical system approximately 2 mm circumferentially cranial to the diseased tissue. The musculature was transected to the level of the vertebral column, disarticulating between the second and third caudal vertebrae and transecting the spinal cord with a no. 15 blade. Lateral vertebral processes of the second vertebra were removed with a rongeur. Coccygeus lateralis muscles and tensor fasciae latae muscles and skin were closed laterolaterally with 2 layers and 3-0 polydioxanone suture. The bird recovered uneventfully and was discharged after 6 days of hospitalization. The histopathological diagnosis was adenocarcinoma with squamous differentiation, marked scirrhous response, and superficial epithelial ulceration. It was determined that narrow margins of unaffected tissue were achieved from the pathological examination of submitted material. The bird was evaluated 24 days after surgery and again 3.5 months after surgery, without evidence of complications or recurrence. Approximately 10 days after the last reexamination, the bird was euthanatized after being found minimally responsive at home. A postmortem examination was not performed.

A novel surgical technique for enucleation in rabbits to reduce the risk of intra- and post-operative orbital hemorrhage.

A 10-year-old male castrated Holland Lop rabbit (Oryctolagus cuniculus) was presented for severe ulcerative stromal keratitis of the right eye and a luxated hypermature cataract and glaucoma of the left eye. Staged bilateral enucleation was elected. A LigaSure™ electrosurgical bipolar vessel-sealing device was used as a means to minimize intraoperative and post-operative hemorrhage, especially that associated with the orbital venous plexus. The LigaSure™ was used to ligate and transect all extraocular muscles, the optic nerve bundle, and the base of the third eyelid with no complications encountered. Overall, the LigaSure™ was easy to use, resulted in minimal hemorrhage, and reduced surgery time. This is the first report of the use of a LigaSure™ to aid in the enucleation of a rabbit. Although only positive results were achieved as an alternative to conventional methodologies, its use in clinical practice should be that of caution until a larger study evaluating the long-term results is performed.

Acremonium and trichosporon fungal keratoconjunctivitis in a Leopard Gecko (Eublepharis macularius).

A 6-year-old male leopard gecko (Eublepharis macularius) was presented with a 2-year history of recurrent dysecdysis involving the ocular surface of both eyes. Ophthalmic examination revealed ocular surface desiccation and multifocal superficial ulcerative keratitis with patchy remnants of retained shed. Other abnormalities included stomatitis and mandibular and maxillary osteomyelitis. Topical and systemic antibiotic therapy, oral vitamin A, and improved husbandry conditions resolved the stomatitis and osteomyelitis but did not improve the ocular surface. Corneal cytology collected with a cytobrush revealed branching hyphae and budding yeast consistent with fungal keratitis. Fungal culture grew Acremonium sp. and Trichosporon sp. The addition of topical antifungal therapy improved the ocular surface health, but the patient was euthanized 7 weeks after initial presentation for persistent vomiting and dyspnea. Necropsy was declined. This case describes the first case of fungal keratitis caused by Acremonium sp. and Trichosporon sp. in a reptile.

Clinical and pathological findings for rabbits with dystocia: 10 cases (1996-2016).

OBJECTIVE: To characterize clinical and pathological findings of rabbits evaluated at a veterinary teaching hospital because of dystocia. DESIGN: Retrospective case series. ANIMALS: 9 client-owned rabbits and 1 wild rabbit with signs of dystocia evaluated at a veterinary teaching hospital from 1996 through 2016. PROCEDURES: Medical records of rabbits were reviewed to collect data on signalment; medical history; physical examination, laboratory, diagnostic imaging, and procedural findings; treatment; final diagnosis; and outcome. Data were summarized. RESULTS: Dystocia in 7 rabbits was successfully managed through medical treatment, assisted vaginal delivery, or both (n = 6) or surgery alone (1); 3 rabbits were euthanized. Primiparous does, does ≤ 4 years old, and does of small breeds (< 2 kg [4.4 lb]) were most common. All client-owned rabbits had clinical signs of abnormal second-stage parturition, whereas the wild rabbit had only hemorrhagic vulvar discharge. Imaging was used to identify the number, size, and state of fetuses in most rabbits. Overall, 35 fetuses were accounted for, 25 of which were dead or later died. The cause of dystocia was determined for 8 rabbits and included fetal-maternal mismatch (n = 4), uterine inertia (2), fetal death or mummification (1), and stress-induced abortion (1). CONCLUSIONS AND CLINICAL RELEVANCE: Obstructive dystocia from fetal macrosomia with or without secondary uterine inertia was the most common cause of dystocia in the evaluated rabbits. Although medical management was successful for many rabbits with dystocia in this study, surgery could still be required in other affected rabbits, particularly when fetal-maternal mismatch is involved.

Pharmacokinetics and safety of zonisamide after oral administration of single and multiple doses to Hispaniolan Amazon parrots (Amazona ventralis).

OBJECTIVE To determine pharmacokinetics after oral administration of single and multiple doses and to assess the safety of zonisamide in Hispaniolan Amazon parrots (Amazona ventralis). ANIMALS 12 adult Hispaniolan Amazon parrots. PROCEDURES Zonisamide (30 mg/kg, PO) was administered once to 6 parrots in a single-dose trial. Six months later, a multiple-dose trial was performed in which 8 parrots received zonisamide (20 mg/kg, PO, q 12 h for 10 days) and 4 parrots served as control birds. Safety was assessed through monitoring of body weight, attitude, and urofeces and comparison of those variables and results of CBC and biochemical analyses between control and treatment groups. RESULTS Mean ± SD maximum plasma concentration of zonisamide for the single- and multiple-dose trials was 21.19 ± 3.42 µg/mL at 4.75 hours and 25.11 ± 1.81 µg/mL at 2.25 hours after administration, respectively. Mean plasma elimination half-life for the single- and multiple-dose trials was 13.34 ± 2.10 hours and 9.76 ± 0.93 hours, respectively. Pharmacokinetic values supported accumulation in the multiple-dose trial. There were no significant differences in body weight, appearance of urofeces, or appetite between treated and control birds. Although treated birds had several significant differences in hematologic and biochemical variables, all variables remained within reference values for this species. CONCLUSIONS AND CLINICAL RELEVANCE Twice-daily oral administration of zonisamide to Hispaniolan Amazon parrots resulted in plasma concentrations known to be therapeutic in dogs without evidence of adverse effects on body weight, attitude, and urofeces or clinically relevant changes to hematologic and biochemical variables.

Genomes of Three Closely Related Caribbean Amazons Provide Insight for Species History and Conservation.

Islands have been used as model systems for studies of speciation and extinction since Darwin published his observations about finches found on the Galapagos. Amazon parrots inhabiting the Greater Antillean Islands represent a fascinating model of species diversification. Unfortunately, many of these birds are threatened as a result of human activity and some, like the Puerto Rican parrot, are now critically endangered. In this study we used a combination of de novo and reference-assisted assembly methods, integrating it with information obtained from related genomes to perform genome reconstruction of three amazon species. First, we used whole genome sequencing data to generate a new de novo genome assembly for the Puerto Rican parrot (Amazona vittata). We then improved the obtained assembly using transcriptome data from Amazona ventralis and used the resulting sequences as a reference to assemble the genomes Hispaniolan (A. ventralis) and Cuban (Amazona leucocephala) parrots. Finally, we, annotated genes and repetitive elements, estimated genome sizes and current levels of heterozygosity, built models of demographic history and provided interpretation of our findings in the context of parrot evolution in the Caribbean.

Evaluation of the thermal antinociceptive effects and pharmacokinetics after intramuscular administration of buprenorphine hydrochloride to cockatiels (Nymphicus hollandicus).

OBJECTIVE To evaluate thermal antinociceptive effects and pharmacokinetics of buprenorphine hydrochloride after IM administration to cockatiels (Nymphicus hollandicus). ANIMALS 16 adult (≥ 2 years old) cockatiels (8 males and 8 females). PROCEDURES Buprenorphine hydrochloride (0.3 mg/mL) at each of 3 doses (0.6, 1.2, and 1.8 mg/kg) and saline (0.9% NaCl) solution (control treatment) were administered IM to birds in a randomized within-subject complete crossover study. Foot withdrawal response to a thermal stimulus was determined before (baseline) and 0.5, 1.5, 3, and 6 hours after treatment administration. Agitation-sedation scores were also determined. For the pharmacokinetic analysis, buprenorphine (0.6 mg/kg) was administered IM to 12 of the birds, and blood samples were collected at 9 time points ranging from 5 minutes to 9 hours after drug administration. Samples were analyzed with liquid chromatography-mass spectrometry. Pharmacokinetic parameters were calculated with commercial software. RESULTS Buprenorphine at 0.6, 1.2, and 1.8 mg/kg did not significantly change the thermal foot withdrawal response, compared with the response for the control treatment. No significant change in agitation-sedation scores was detected between all doses of buprenorphine and the control treatment. Plasma buprenorphine concentrations were > 1 ng/mL in all 4 birds evaluated at 9 hours. CONCLUSIONS AND CLINICAL RELEVANCE Buprenorphine at the doses evaluated did not significantly change the thermal nociceptive threshold for cockatiels or cause sedative or agitative effects. Additional studies with other pain assessments and drug doses are needed to evaluate the analgesic and adverse effects of buprenorphine in cockatiels and other avian species.

Evaluation of the thermal antinociceptive effects and pharmacokinetics of hydromorphone hydrochloride after intramuscular administration to cockatiels (Nymphicus hollandicus).

OBJECTIVE To evaluate the thermal antinociceptive effects and pharmacokinetics of hydromorphone hydrochloride after IM administration to cockatiels (Nymphicus hollandicus). ANIMALS 16 healthy adult cockatiels. PROCEDURES During the first of 2 study phases, each cockatiel received each of 4 treatments (hydromorphone at doses of 0.1, 0.3, and 0.6 mg/kg and saline [0.9% NaCl] solution [0.33 mL/kg; control], IM), with a 14-day interval between treatments. For each bird, foot withdrawal to a thermal stimulus was determined following assignment of an agitation-sedation score at predetermined times before and for 6 hours after each treatment. During the second phase, a subset of 12 birds received hydromorphone (0.6 mg/kg, IM), and blood samples were collected at predetermined times for 9 hours after drug administration. Plasma hydromorphone concentration was determined by liquid chromatography-mass spectrometry. Noncompartmental analysis of sparse data was used to calculate pharmacokinetic parameters. RESULTS Thermal withdrawal response did not differ among the 4 treatment groups at any time. Agitation-sedation scores following administration of the 0.3-and 0.6-mg/kg doses of hydromorphone differed significantly from those treated with saline solution and suggested the drug had a sedative effect. Plasma hydromorphone concentrations were > 1 ng/mL for 3 to 6 hours after drug administration in all birds. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that IM administration of hydromorphone at the evaluated doses did not increase the thermal withdrawal threshold of cockatiels despite plasma drug concentrations considered therapeutic for other species. Further research is necessary to evaluate the analgesic effects of hydromorphone in cockatiels.