The objectives of this retrospective study were 1) to characterize humeral fractures in raptors at a rehabilitation program, 2) to determine risk factors for closed and compound humeral fractures in the raptors, and 3) to investigate prognostic factors for humeral fractures in raptors. Of the 6017 birds of prey admitted over 15 years to the Université de Montréal raptor rehabilitation program, 461 birds presented with a humeral fracture. The highest occurrences of humeral fractures were documented in short-eared owls (33%; Asio flammeus), Northern hawk-owls (24%; Surnia ulula), long-eared owls (20%; Asio otus), and Northern harriers (19%; Circus hudsonius). Humeral fractures were more common in males, and species from the intermediate weight group (300 g to 1 kg) were more likely to have compound humeral fractures than birds from the lower and higher weight groups. Humeral fractures of the middle and distal third of the bone were diagnosed as compound more often than fractures of the proximal third. A correlation between the occurrences of humeral fractures and the relative average width of the humerus for each species was observed and suggests that species with slender humeri have an increased likelihood of compound humeral fractures. Following the triage criteria used at this rehabilitation program, surgical (119 birds) or nonsurgical (77 birds) treatments were attempted. Release rate for birds without concomitant conditions in which a treatment was attempted was 39.3% (59/150) and did not significantly differ between closed and compound fractures, which suggests that the triage criteria used for compound fractures in this program were adequate. Our findings emphasize that raptors should not be systematically euthanatized when presented with compound humeral fractures to a rehabilitation facility.

Surgical amputation of a limb is often required to treat raptor orthopedic injuries at rehabilitation centers. In some cases, amputation is an alternative to euthanasia if the bird's welfare is deemed appropriate under human care. The outcome for raptors maintained in a captive setting following wing amputation is poorly documented. A retrospective study was conducted in a Canadian raptor rehabilitation facility to assess the outcomes and complications observed in captive and free-living raptors with partial or complete, surgical or traumatic amputations of the wing. Data from raptors admitted to the rehabilitation center from 1995 to 2017 were reviewed. Overall, 32 records were included in this retrospective study from 11 species of raptors with surgical or traumatic wing amputations. Survival times of the 23 birds with an amputated wing (median: 1070 days, range: 68 days to 13 years and 1 month) were significantly (P = .02) longer than the survival times of the 404 non-amputated birds (median: 696 days, range 37 days to 27 years and 3 months). Complications occurred in 13 of 30 birds (43%) during the recovery period, with 9 of 30 (30%) birds developing life-threatening complications. Maladaptation to captivity was the leading cause of euthanasia during this period. After placement in captivity, 3/23 (13%) birds developed complications related to the amputation site. Based on this study, we conclude that some birds can tolerate partial or complete wing amputation, but the decision to place a bird in a captive setting should encompass the bird's ability to cope with human interaction and the availability of an adapted and safe enclosure for the animal.

The objective of this study was to compare the sedative effects of intramuscular alfaxalone combined with either ketamine or midazolam in chickens (Gallus gallus domesticus). A prospective, randomized blinded crossover study design with a 7-day washout period was used. Nine adult layer hens received alfaxalone 15 mg/kg with ketamine 5 mg/kg IM (treatment AK) or alfaxalone 15 mg/kg with midazolam 1 mg/kg IM (treatment AM). Time to lateral recumbency, time to loss of righting reflex, induction quality, duration of loss of righting reflex, time to sternal recumbency or vigorous response to stimulation, and time to standing were recorded. Muscle tone, response to noxious stimulation, heart rate, respiratory rate, and oxygen saturation were monitored once the righting reflex was absent. Induction and recovery times were not different between treatments. Lateral recumbency was induced in 8 of 9 birds receiving AK compared to 6 of 9 birds receiving AM. Righting reflex was absent in 7 of 9 and 5 of 9 chickens administered AK and AM, respectively. Median time to loss of righting reflex for AK and AM were 5.5 (4.3–9.3) minutes and 9.1 (4.8–15.0) minutes, respectively (P = .88). Median duration of loss of righting reflex was 21.6 (16.0–36.9) minutes for AK and 21.1 (11.9–26.4) minutes for AM (P = .38). Alfaxalone-ketamine resulted in moderate excitation during induction. Further investigations are warranted to investigate the effects of alfaxalone and midazolam or ketamine at different doses.

The objective of this study was to construct a calibration phantom for bone mineral density (BMD) measurements adapted to avian anatomy by quantitative computed tomography. The determination of BMD is important to assess avian osteoporosis in poultry at production facilities and to study biological features in association with flight patterns in birds. Quantitative computed tomography measured in Hounsfield units is a well-established technique for BMD measurements. Translation of Hounsfield units into the International System of Units (mg/cm³) requires the use of a calibration phantom. Although calibration phantoms for routine use in humans are commercially available, phantoms suited to avian anatomy are not. A liquid dipotassium hydrogen phosphate calibration standard was constructed out of commercially available materials, easily allowing for variations in size, bone diameter, and adaptation to avian skeletal anatomy. Periodically, quantitative computed tomography scans were performed to monitor constant correlation to the calibration standard over 3 months and to monitor for the potential influence of gas bubbling and water evaporation in the rods on BMD measurements. Finally, the calibration phantom was tested for BMD measurements with carcasses from 2 bird species, including 3 peregrine falcons (Falco peregrinus; 2 juvenile males, 1 adult female with inactive reproductive status) and 4 Eurasian kestrels (Falco tinnunculus; 1 juvenile and 2 adult males, 1 adult female with inactive reproductive status). Results demonstrated stability of the calibration phantom without the need to refill or replace rods, plus a stable correlation line (R² = .99) over the 3-month evaluation period. It was possible to place the phantom directly on the bird carcasses, close to the measured bones, to improve BMD analysis. As evaluated, the phantom appeared to be adaptive to avian skeletal anatomy. Moreover, it was possible to build the phantom within 24 hours from commercially available materials.

Egg binding and excessive laying frequently affect avian patients, and in many cases the treatment includes suppression of egg production. Currently, for the suppression of egg production in avian patients, a gonadotropin-releasing hormone agonist, in the form of a deslorelin implant, is often used. However, the commercially available deslorelin implants have an undesired delayed onset, as well as a potential brief increase in gonadotropin secretion after administration (“flare-up” effect) that can lead to oviposition before the actual suppression of gonadotropins. The objective of this study was to investigate whether the prolactin inhibitor cabergoline suppresses ovulation and whether it could be used to bridge the time until the onset of effect by the deslorelin implant. We measured the effect of cabergoline (30 µg/kg PO q24h × 14 days), deslorelin implants (4.7 mg SC), and a combination of both on egg laying and plasma prolactin concentrations in 37 quail (Coturnix japonica) over 6 weeks. Quail were divided into 4 groups: group DesCab (deslorelin implant and cabergoline oral; n = 9); group DesPlac (deslorelin implant and placebo oral; n = 9); group PlacCab (placebo implant and cabergoline oral; n = 9); and group PlacPlac (placebo implant and placebo oral; n = 10). Regular egg laying stopped in 100% (9/9) of birds in group DesCab and 78% (7/ 9) of birds in group DesPlac within 5 days of placing the deslorelin implant. No bird ceased egg production in group PlacCab (0/9), and 10% of birds ceased egg production intermittently in group PlacPlac (1/10). Treatment with the deslorelin implant (P < .001) and with cabergoline (P = .04) had a significant (negative) influence on plasma prolactin concentrations compared with the baseline. The interaction of deslorelin and cabergoline treatment, as well as time after initiation of treatment, did not have a significant effect on plasma prolactin concentrations. These results show that daily oral cabergoline has no significant influence on egg laying and only a minor biologically nonsignificant effect on lowering the relative plasma prolactin concentrations in quail.

Currently, drug-induced stimulation of appetite is not commonly performed in hyporexic or anorexic companion psittacine birds. Instead, to prevent a catabolic state and weight loss, supplemental feedings are routinely performed by crop gavage. However, crop gavage is not without complications and is stressful to the patient and labor intensive. The objective of this study was to evaluate the effect of midazolam on food intake in healthy budgerigars. In a randomized, blinded, controlled study, change in food intake after intramuscular administration of midazolam (1 mg/kg) or a placebo-control treatment (0.9% saline) was evaluated in 12 healthy adult budgerigars (Melopsittacus undulatus). Food intake was quantified for 1 hour before and after drug administration. Birds were monitored for feeding behavior as well as signs of sedation. After midazolam administration, a median 6-fold (1.1–28) increase in food intake was recorded. In 3 of 6 (50%) birds, the food intake increase after midazolam administration was >10-fold (median 17-fold [10–28]), whereas in the remaining 3 birds, food intake increased by only 1.7-fold (1.1–1.8). The median amount of food ingested (16.7 g/kg [3.2–43.2 g/kg]) was significantly higher after midazolam administration compared with the control group (1.9 g/kg [0.0–19.7 g/kg], P = .015). The median time birds spent displaying feeding behavior after the midazolam injection was 18% (0–43%), compared with 1% (0–20%) in the control group after saline injection. Five of 6 (83%) birds showed signs consistent with mild sedation after midazolam administration. This study demonstrates that midazolam is an appetite stimulant in budgerigars. Future studies are needed to evaluate whether midazolam's effects on food intake are dose dependent and whether the duration of effect exceeds 1 hour.

A juvenile red-tailed hawk (Buteo jamaicensis) was presented to the Ontario Veterinary College from a wildlife rehabilitation facility for the assessment of an arrowhead foreign body injury. The hawk was found on the ground with the left wing in a dropped position. Radiographic images revealed an arrowhead foreign body superimposed over the left lung and thoracic air sacs, immediately medial to the ribs on the ventrodorsal view, and ventral to the scapulae on the right latero-lateral view. A coelioscopy was performed using a left lateral approach with a 2.7-mm rigid endoscope into the left caudal thoracic air sac, with an additional instrument port through the left abdominal air sac. The arrowhead was visualized adjacent to the left lung, separated from the cranial thoracic air sac cavity by a membrane of fibrous tissue. The tissue membrane was radiosurgically incised. Forceps were then used to guide an Endoloop around the arrowhead. The arrowhead was secured by tightening the Endoloop, and the body wall incision was extended to facilitate the arrowhead extraction.

Envenomation in avian species can result in death, with few cases of successful treatment described. A juvenile, wild-caught, intact female red-tailed hawk (Buteo jamaicensis) used in falconry was presented for emergency evaluation after being bitten by a Northern Pacific rattlesnake (Crotalus oreganus) approximately 2 hours before presentation. On presentation, the bird was quiet, alert, and responsive, with moderate swelling and discomfort of the digits on the right foot. Complete blood count (CBC) and plasma biochemistry abnormalities included a regenerative left shift, severe lymphopenia, and a moderate hypoproteinemia characterized by moderate hypoalbuminemia. Analgesic and antibiotic medications were administered during hospitalization. In addition, 5 mL of VenomVet was administered intravenously with crystalloid fluids over 60 minutes; no adverse effects were noted secondary to infusion. Improvement in the swelling was observed immediately after antivenom administration and nearly resolved within 12 hours. Complete resolution of digital swelling with no discomfort on palpation of that foot was observed 1 week after initial presentation. Blood collected at the 1 week reexamination was submitted for a CBC and plasma biochemistry panel. The results of the CBC revealed a reduced regenerative left shift, increased heterophil count, and a moderate monocytosis; the lymphopenia was resolved. A mild hypoalbuminemia still persisted. Ten months after presentation, the bird was reported to be doing well with no changes in function of the right foot and subsequently released from captivity.

A 2-year-old domestic hen was presented for a 15-day history of intermittent left leg lameness. The owners also observed a decrease in egg quality during that period. Physical examination of the bird revealed a generalized weakness with a flattened pale comb. Neurological evaluation of the left leg found a proprioceptive deficit with no loss of pain sensitivity. Whole body radiographic images showed a marked reduction of abdominal detail, a large amount of “grit” (mineral opacity) in the ventriculus, intestinal dilation, and a metallic foreign body (nail) in the digestive tract. Abnormal results from a plasma biochemistry panel were hypercalcemia, hypertriglyceridemia, hyperglobulinemia, hypophosphatemia, increased creatine kinase, and decreased uric acid. After initial stabilization of the patient, a computed tomographic scan was obtained, which revealed multiple right-sided ureteral calculi, the largest of which measured 10 mm in diameter, and changes compatible with cystic right renal nephrosis. Suspected compensatory enlargement of the left kidney was also observed. Considering the renal lesion and associated neurological limb impairment, surgery was recommended and approved by the owner. A right lateral approach was used for the coeliotomy, and a ureterotomy was performed to remove all calculi. Analysis of the ureteral stones confirmed they were 100% uric acid salts. The hen fully recovered left leg function 1 week postsurgery. Urolithiasis is well described in hens, but surgical treatment is uncommon. This report describes the successful removal of ureteral stones by ureterotomy in a domestic hen.

A free ranging, fledged common buzzard (Buteo buteo) was found with severe feather damage and left periorbital swelling. Clinical examination revealed a 3.0 × 2.5 × 1.5 cm left medial subconjunctival mass. The abnormal tissue extended over most of the left cornea, severely impairing the bird's vision in that eye. Additionally, the left globe was displaced in a temporal direction. Computed tomography revealed the origin of the mass to be retrobulbar tissue. An ultrasound examination of the mass found cystic areas, and a sanguineous fluid was aspirated. Cytological examination of the aspirated fluid revealed numerous erythrocytes and a few round cells with oval nuclei, single large nucleoli, and abundant foamy cytoplasm. After a poor prognosis for rehabilitation to the wild, the bird was humanely euthanatized. A postmortem examination of the bird confirmed the retrobulbar mass with extension around the bulbus. Histological examination of the mass was consistent with an invasive adenocarcinoma, likely arising from the lacrimal glands. Neoplasia in the orbit has occasionally been described in Psittaciformes, but only rarely in birds of prey such as Accipitriformes.

West Nile virus (WNV) has had a significant effect on avian populations in the United States since being first identified in 1999. Avian species in WNV endemic areas do not suffer the same level of mortality that has been reported in birds within the United States since the virus was first identified in North America. Because of their unique susceptibility, American crows (Corvus brachyrhynchos) are often used to monitor the spread and severity of WNV in North America. American crows with WNV infections are received and treated at the Janet L. Swanson Wildlife Hospital (Cornell University, Ithaca, NY, USA) on a regular basis during the summer and fall and have historically had a 100% mortality rate. This report describes WNV-positive American crows that were treated, recovered from the infection, and were subsequently released. The 5 American crows in this case series were tested, when possible, by polymerase chain reaction (PCR) and plaque reduction neutralization on admission and monitored with both PCR and plaque reduction neutralization throughout their rehabilitation process. Four of the 5 birds had a negative PCR test before release, and 1 bird had a “suspect” positive PCR test result before release. One of the crows was confirmed to have survived for at least 2.5 years after release. Viral shedding was documented up to 93 days after initial hospitalization, which is longer than any previous report of WNV shedding in an American crow.