Procedures—2 crossover experiments were conducted. In the first experiment, 15 parrots received 3 treatments (tramadol at 2 doses [10 and 20 mg/kg] and a control suspension) administered orally. In the second experiment, 11 parrots received 2 treatments (tramadol hydrochloride [30 mg/kg] and a control suspension) administered orally. Baseline thermal foot withdrawal threshold was measured 1 hour before drug or control suspension administration; thermal foot withdrawal threshold was measured after administration at 0.5, 1.5, 3, and 6 hours (both experiments) and also at 9 hours (second experiment only).
Results—For the first experiment, there were no overall effects of treatment, hour, period, or any interactions. For the second experiment, there was an overall effect of treatment, with a significant difference between tramadol hydrochloride and control suspension (mean change from baseline, 2.00° and −0.09°C, respectively). There also was a significant change from baseline for tramadol hydrochloride at 0.5, 1.5, and 6 hours after administration but not at 3 or 9 hours after administration.
Conclusions and Clinical Relevance—Tramadol at a dose of 30 mg/kg, PO, induced thermal antinociception in Hispaniolan Amazon parrots. This dose was necessary for induction of significant and sustained analgesic effects, with duration of action up to 6 hours. Further studies with other types of noxious stimulation, dosages, and intervals are needed to fully evaluate the analgesic effects of tramadol hydrochloride in psittacines.
To determine the pharmacokinetics of butorphanol tartrate incorporated into poloxamer 407 (P407) after subcutaneous administration to orange-winged Amazon parrots (Amazona amazonica).
Six orange-winged Amazon parrots, ages 28 to 45 years.
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.
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.
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.
To evaluate a carrageenan-induced inflammatory model in the cockatiel (Nymphicus hollandicus) using weight-bearing load, rotational perch locomotion, thermal threshold withdrawal, and footpad dimensions.
16 adult cockatiels (8 males and 8 females).
Cockatiels were randomly assigned into 2 groups as either treatment (carrageenan injection; n = 8) or control (handling only; 8). Treatment of cockatiels involved unilateral subcutaneous injection of 0.05 mL of 1% lambda carrageenan solution into the left footpad. Control birds were handled in a similar manner without an injection. Following baseline measurements and treatment or control procedures, posttreatment measurements at multiple time points involving weight-bearing perch load (for up to 336 hours), locomotive abilities when placed on a rotating perch (for up to 96 hours), thermal withdrawal threshold (for the 24- to 30-hour period), and both vertical and horizontal left footpad size and degree of swelling (for up to 84 days) were obtained.
Treatment cockatiels had a significant decrease in left foot weight-bearing load and increase in left footpad dimensions and swelling grade over time compared to control cockatiels. Rotational perch locomotion and thermal withdrawal threshold, conversely, did not differ significantly between groups. Cockatiels injected with carrageenan returned to normal weight-bearing within 2 weeks; however, left footpad dimensions did not return to baseline.
Carrageenan footpad injection prompts a measurable and grossly visible inflammatory response in the cockatiel. Additionally, it induces alterations in weight-bearing distribution in injected birds. This model provides a method to evaluate inflammation and lameness in small psittacine species.
OBJECTIVE To determine the mydriatic effects of topical rocuronium bromide administration in Hispaniolan Amazon parrots (Amazona ventralis) and to identify any adverse effects associated with treatment.
PROCEDURES Rocuronium bromide (20 μL/eye; 10 mg/mL) or saline (20 μL/eye; 0.9% NaCl) solution was administered in both eyes of each bird with a 26-day washout period. The birds were manually restrained in lateral recumbency with the apex of the cornea positioned upward for 2 minutes following administration in each eye. Infrared pupillometry and direct pupillary light reflex measurements were used to evaluate the mydriatic effects. Pupillary measurements were recorded prior to administration and every 20 minutes for 2 hours after administration, then hourly for a total of 7 hours. A brief physical examination was performed, direct pupillary light reflex was tested, and fluorescein staining was performed on each eye of each bird 24 hours after administration.
RESULTS A significant difference in pupillary diameter for the active versus control treatment group was noted from 20 to 360 minutes after drug administration, but not at 420 minutes. Minimal adverse effects were noted. Three birds had transient inferior eyelid paresis noted in both eyes after receiving rocuronium; 24 hours after the treatment, no differences in ocular measurements existed between the active and control treatments.
CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that topical rocuronium bromide administration may be safely used for pupillary dilation in Hispaniolan Amazon parrots and could be used for clinical evaluation, fundus imaging, and surgical interventions involving the lens and posterior segment in this species.
Objective—To determine the prevalence of heart murmurs in chinchillas (Chinchilla lanigera) and determine whether heart murmurs were associated with cardiac disease.
Design—Retrospective multi-institutional case series.
Procedures—Medical records of all chinchilla patients evaluated at the Tufts University Foster Hospital for Small Animals between 2001 and 2009, the University of California-Davis William R. Pritchard Veterinary Medical Teaching Hospital between 1996 and 2009, and the University of Wisconsin Veterinary Medical Teaching Hospital between 1998 and 2009 were reviewed.
Results—Prevalence of heart murmurs was 23% (59/260). Of 15 chinchillas with heart murmurs that underwent echocardiography, 8 had echocardiographic abnormalities, including dynamic right ventricular outflow tract obstruction, mitral regurgitation, hypertrophy of the left ventricle, tricuspid regurgitation, and hypovolemia. Echocardiographic abnormalities were approximately 29 times as likely (OR, 28.7) to be present in chinchillas with a murmur of grade 3 or higher than in chinchillas without a murmur.
Conclusions and Clinical Relevance—Results suggested that heart murmurs are common in chinchillas and that chinchillas with heart murmurs often have echocardiographic abnormalities, with valvular disease being the most common. On the basis of these results, we believe that echocardiography should be recommended for chinchillas with heart murmurs, especially older chinchillas with murmurs of grade 3 or higher. Further prospective studies are needed to accurately evaluate the prevalence of cardiac disease in chinchillas with heart murmurs.
Objective—To evaluate serial blood gas values and lactate concentrations in 3 fish species undergoing surgery and to compare blood lactate concentrations between fish that survived and those that died during the short-term postoperative period.
Design—Prospective cohort study.
Animals—10 yellow perch, 5 walleye pike, and 8 koi.
Procedures—Blood samples were collected from each fish at 3 time points: before anesthesia, during anesthesia, and immediately after surgery. Blood gas values and blood lactate concentrations were measured. Fish were monitored for 2 weeks postoperatively.
Results—All walleye and koi survived, but 2 perch died. Blood pH significantly decreased in perch from before to during anesthesia, but increased back to preanesthesia baseline values after surgery. Blood Pco2 decreased significantly in perch from before anesthesia to immediately after surgery, and also from during anesthesia to immediately after surgery, whereas blood Pco2 decreased significantly in koi from before to during anesthesia. Blood Po2 increased significantly in both perch and koi from before to during anesthesia, and also in koi from before anesthesia to immediately after surgery. For all 3 species, blood lactate concentrations increased significantly from before anesthesia to immediately after surgery. Blood lactate concentration (mean ± SD) immediately after surgery for the 8 surviving perch was 6.06 ± 1.47 mmol/L, which was significantly lower than blood lactate concentrations in the 2 nonsurviving perch (10.58 and 10.72 mmol/L).
Conclusions and Clinical Relevance—High blood lactate concentrations following surgery in fish may be predictive of a poor short-term postoperative survival rate.
Objective—To assess the pharmacokinetics of nalbuphine HCl after IV and IM administration to Hispaniolan Amazon parrots (Amazona ventralis).
Animals—8 healthy adult Hispaniolan Amazon parrots of unknown sex.
Procedures—Nalbuphine HCl (12.5 mg/kg) was administered IV and IM to all birds in a complete randomized crossover study design; there was a washout period of 21 days between subsequent administrations. Plasma samples were obtained from blood collected at predetermined time points for measurement of nalbuphine concentration by use of liquid chromatography–tandem mass spectrometry. Pharmacokinetic parameters were estimated by use of computer software.
Results—Nalbuphine was rapidly eliminated with a terminal half-life of 0.33 hours and clearance of 69.95 mL/min/kg after IV administration and a half-life of 0.35 hours after IM administration. Volume of distribution was 2.01 L/kg after IV administration. The fraction of the dose absorbed was high (1.03) after IM administration. No adverse effects were detected in the parrots during the study.
Conclusions and Clinical Relevance—In Hispaniolan Amazon parrots, nalbuphine appeared to have good bioavailability after IM administration and was rapidly cleared after IV and IM administration. Safety and analgesic efficacy of various nalbuphine treatment regimens in this species require further investigation to determine the potential for clinical palliation of signs of pain in psittacine species.
Objective—To evaluate injection of microcrystalline sodium urate (MSU) for inducing articular pain in green-cheeked conures (Pyrrhura molinae) and the analgesic efficacy of liposome-encapsulated butorphanol tartrate (LEBT) by use of weight load data, behavioral scores, and fecal corticosterone concentration.
Procedures—In a crossover study, conures were randomly assigned to receive LEBT (15 mg/kg) or liposomal vehicle subsequent to experimental induction of arthritis or sham injection. The MSU was injected into 1 tibiotarsal-tarsometatarsal (intertarsal) joint to induce arthritis (time 0). Weight-bearing load and behavioral scores were determined at 0, 2, 6, 26, and 30 hours.
Results—MSU injection into 1 intertarsal joint caused a temporary decrease in weight bearing on the affected limb. Treatment of arthritic conures with LEBT resulted in significantly more weight bearing on the arthritic limb than treatment with vehicle. Administration of vehicle to arthritic conures caused a decrease in activity and feeding behaviors during the induction phase of arthritis, but as the arthritis resolved, there was a significant increase in voluntary activity at 30 hours and feeding behaviors at 26 and 30 hours, compared with results for LEBT treatment of arthritic birds. Treatment with LEBT or vehicle in conures without arthritis resulted in similar measurements for weight bearing and voluntary and motivated behaviors.
Conclusions and Clinical Relevance—Experimental induction of arthritis in conures was a good method for evaluating tonic pain. Weight-bearing load was the most sensitive measure of pain associated with induced arthritis. Pain associated with MSU-induced arthritis was alleviated by administration of LEBT.
OBJECTIVE To investigate renal, gastrointestinal, and hemostatic effects associated with oral administration of multiple doses of meloxicam to healthy Hispaniolan Amazon parrots (Amazona ventralis).
ANIMALS 12 Hispaniolan Amazon parrots.
PROCEDURES Birds were assigned to receive meloxicam oral suspension (1.6 mg/kg, PO, q 12 h) and 2.5 mL of tap water inserted into the crop by use of a gavage tube (n = 8) or the equivalent volume of tap water only (control group; 4) for 15 days. Urine and feces were collected 2 hours after treatment administration each day. Feces were evaluated for occult blood. Results of a CBC and serum biochemical analysis and measured N-acetyl-β-d-glucosaminidase (NAG) activity and whole blood clotting time were evaluated before, during, and after completion of treatments. Results of urinalysis and measured urine NAG activity were also evaluated.
RESULTS Birds treated with meloxicam had a significant increase in number of WBCs and decrease in PCV from before to after treatment. The PCV also decreased significantly, compared with results for the control group; however, WBC count and PCV for all birds remained within reference ranges throughout the study. One parrot treated with meloxicam had a single high value for urine NAG activity.
CONCLUSIONS AND CLINICAL RELEVANCE Meloxicam administered orally at the dosage used in this study caused no apparent negative changes in several renal, gastrointestinal, or hemostatic variables in healthy Hispaniolan Amazon parrots. Additional studies to evaluate adverse effects of NSAIDs in birds will be needed.