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.

OBJECTIVE To compare sedation in cockatiels (Nymphicus hollandicus) after intranasal administration of midazolam and midazolam-butorphanol. ANIMALS 9 healthy adult cockatiels. PROCEDURES A randomized, controlled, blinded, complete crossover study was conducted. Birds were assigned to 3 treatment groups. Midazolam (3 mg/kg), midazolam-butorphanol (3 mg/kg for each drug), or sterile saline (0.9% NaCl) solution (control treatment) was administered intranasally. Sedation quality was assessed at 3 time points by use of eye and body position; response to visual, auditory, and tactile stimulation; and response during manual restraint on the basis of eye position and struggling intensity. To evaluate attenuation of the manual restraint–induced stress response, heart rate, respiratory rate, and cloacal temperature were measured over a 15-minute period. Treatments were repeated after a minimum washout period of 7 days. RESULTS Median onset of first sedation effects was 85 seconds (range, 60 to 120 seconds) for midazolam and 90 seconds (range, 45 to 180 seconds) for midazolam-butorphanol. Midazolam-butorphanol resulted in significantly less vigorous struggling during restraint than did midazolam or the control treatment. Heart rate did not differ significantly among treatments. The stress-induced increase in respiratory rate was significantly attenuated by midazolam and midazolam-butorphanol, whereas the increase in cloacal temperature was not attenuated by midazolam or midazolam-butorphanol. CONCLUSIONS AND CLINICAL RELEVANCE Intranasal administration of midazolam and midazolam-butorphanol resulted in a rapid onset of sedation in cockatiels. Midazolam-butorphanol resulted in deeper sedation in both restrained and unrestrained birds than did midazolam alone. Midazolam and midazolam-butorphanol both provided safe and effective sedation in cockatiels.

OBJECTIVE To describe the torsional and axial compressive properties of tibiotarsal bones of red-tailed hawks (Buteo jamaicensis). SAMPLE 16 cadaveric tibiotarsal bones from 8 red-tailed hawks. PROCEDURES 1 tibiotarsal bone from each bird was randomly assigned to be tested in torsion, and the contralateral bone was tested in axial compression. Intact bones were monotonically loaded in either torsion (n = 8) or axial compression (8) to failure. Mechanical variables were derived from load-deformation curves. Fracture configurations were described. Effects of sex, limb side, and bone dimensions on mechanical properties were assessed with a mixed-model ANOVA. Correlations between equivalent torsional and compressive properties were determined. RESULTS Limb side and bone dimensions were not associated with any mechanical property. During compression tests, mean ultimate cumulative energy and postyield energy for female bones were significantly greater than those for male bones. All 8 bones developed a spiral diaphyseal fracture and a metaphyseal fissure or fracture during torsional tests. During compression tests, all bones developed a crushed metaphysis and a fissure or comminuted fracture of the diaphysis. Positive correlations were apparent between most yield and ultimate torsional and compressive properties. CONCLUSIONS AND CLINICAL RELEVANCE The torsional and axial compressive properties of tibiotarsal bones described in this study can be used as a reference for investigations into fixation methods for tibiotarsal fractures in red-tailed hawks. Although the comminuted and spiral diaphyseal fractures induced in this study were consistent with those observed in clinical practice, the metaphyseal disruption observed was not and warrants further research.

OBJECTIVE To evaluate 3 contrast medium infusion (CMI) protocols for CT angiography (CTA) and measurement of major artery diameters in African grey parrots (Psittacus erithacus). ANIMALS 9 African grey parrots with no detectable cardiovascular disease. PROCEDURES Each bird was anesthetized and underwent placement of an IV catheter in the left basilic vein and 16-slice CTA scanning (started at peak aortic enhancement) with each of 3 CMI protocols at ≥ 1-month intervals. Protocol 1 involved catheter flushing with saline (0.9% NaCl) solution and IV infusion of iopamidol (2 mL) followed by saline solution (0.2 mL; total infused volume, 5 mL). Protocol 2 involved IV infusion of iopamidol (2 mL) followed by saline solution (0.4 mL; total infused volume, 2.4 mL). Protocol 3 involved catheter flushing with saline solution and IV administration of iopamidol (2 mL; total infused volume, 4.8 mL). The diameters of 6 major arteries were measured by 2 observers, and intra- and interobserver agreement, time-enhancement variables, and patient factors affecting contrast medium enhancement were assessed. RESULTS Among the 3 CMI protocols, CTA-derived arterial diameters differed significantly. Measurements obtained with protocol 2 were significantly larger than those obtained with the other protocols. Uniformity of the time-enhancement variables differed among CMI protocols. Patient factors had nonsignificant effects on contrast medium enhancement. CONCLUSIONS AND CLINICAL RELEVANCE Of the CMI protocols assessed, a 2-phase CMI protocol with a post-CMI saline solution flush was the most reliable for CTA-derived measurements of the major thoracic and abdominal arteries in African grey parrots. However, further technique modification is needed.