Autologous bone marrow, alone or as a composite marrow graft, has received much attention in various species. To assess the potential osteogenicity of autologous, extramedullary bone marrow implants in an avian model, 24 adult pigeons (Columba livia) were given intramuscular implantations of autologous marrow aspirated from the medial tibiotarsus. Birds were euthanatized at 1, 4, 6, 8, 10, and 12 weeks after surgery to evaluate whether ectopic bone had formed at the implant sites. Primary evaluations by in situ radiography and postmortem histologic examinations showed no evidence of bone formation. Further evaluation with histologic scores and histomorphometry revealed a significantly increased rate of angiogenesis at the implant sites by the sixth and tenth week postimplantation (P < .05). No significant differences between the treatment and control sites were present at any other endpoints. Results of this study show that, although autologous bone marrow lacks heterotopic osteogenic potentials in this avian model, it could still function as a useful adjunct to routine bone grafting techniques because of its unique capabilities to promote early angiogenesis.

Radiology is an important diagnostic instrument in avian medicine, but standard measurement ranges for the objective evaluation of radiographs of birds are rare. To establish radiographic reference ranges for the critically endangered Spix's macaw (Cyanopsitta spixii), we measured radiographic silhouettes of the heart, liver, kidneys, spleen, proventriculus, and keel of the sternum on 29 radiographs taken under standardized conditions in adult and juvenile, clinically healthy birds. Ratios were determined for the proventricular diameter-to-keel height, the width of the heart to the width of the thorax, and for the “hourglass shape” (ratio of the width of the heart to the width of the liver). No significant differences were found between the sexes among the adult birds. Compared with adult birds, juvenile females had a significantly larger heart width (19.8 ± 1.4 mm versus 21.2 ± 0.7 mm), ratio of the heart width to the thorax width (0.86 ± 0.08 versus 0.94 ± 0.09), and horizontal width of the spleen (7.7 ± 0.6 mm versus 8.5 ± 0.4 mm). Results of radiographic measurements in the Spix's macaws were comparable to those published from other psittacine species. These reference ranges will facilitate a more objective radiographic evaluation of captive Spix's macaws.

To determine the plasma concentration of clindamycin in pigeons after oral administration, 12 rock pigeons (Columba livia) were used in a 2-phase study. In the first phase, 8 pigeons received clindamycin by gavage at 100 mg/kg as a single dose. Blood samples were collected at 0, 0.25, 0.5, 1, 2, 3, 4, and 6 hours, and the plasma was separated, frozen, and subsequently analyzed by liquid chromatography-mass spectrometry for clindamycin and its active metabolites, N-demethylclindamycin (NCLD) and clindamycin sulfoxide. Clindamycin was rapidly absorbed with plasma concentrations peaking at 0.5 hours at 1.43 µg/mL. The terminal half-life (t_1/2) was 1.25 hours, and the mean residence time was 2.49 hours. N-demethylclindamycin was detected in 7 of 8 birds (88%), whereas clindamycin sulfoxide was not found in any samples. In phase 2, clindamycin was administered to 3 birds by gavage at 100 mg/kg q6h for 5 doses. Mean peak plasma concentrations were 2.46 and 0.64 µg/mL, with trough concentrations of 0.11 and 0.44 µg/mL for clindamycin and NCLD, respectively. No adverse effects were observed in any birds. Based on an additive antimicrobial effect of NCLD with clindamycin, an oral dosage of 100 mg/kg q6h in pigeons should reach effective plasma concentrations against common susceptible pathogens. If dose proportionality exists, lower doses and longer intervals likely produce subtherapeutic concentrations to treat systemic infections. How well birds would tolerate an extended oral dose regimen, how frequently birds fail to produce the active metabolite critical for an additive effect, and the application of these results to other avian species require further study.

A 25-year-old yellow-naped Amazon parrot (Amazona ochrocephala auropalliata) was presented for nasal discharge and sneezing. Physical examination revealed poor feather quality, a mild serous nasal discharge, and a mass on the dorsal surface of the oral cavity. Cytologic examination of a mass aspirate as well as results of a choanal culture revealed squamous metaplasia of the salivary glands and bacterial rhinitis, respectively. Following resolution of the presenting conditions, the patient was presented for hind limb weakness and ataxia. The clinical signs were transient and generally resolved with rest but could be reproduced after stressful episodes, such as restraint for procedures or treatment. Test results from a complete blood count, biochemistry profile, whole-body radiographs, needle electromyography of the leg muscles, and an edrophonium challenge test were within reference limits. Based on the clinical signs and results of the diagnostic workup, the presumptive diagnosis was intermittent claudication, a condition caused by peripheral vascular disease and defined as intermittent weakness and pain in the legs induced by exercise and relieved by rest. Shortly after initiation of treatment with isoxsuprine, the bird died. Postmortem examination and histopathology revealed severe atherosclerotic lesions throughout the vascular system with stenotic lesions present in the abdominal aorta and femoral arteries. Electron microscopic examination of the great arteries was also performed and helped to further characterize the nature of the lesions. This case is the first report, to our knowledge, of an intermittent claudication-like syndrome associated with peripheral atherosclerosis in a psittacine bird. In addition, the distribution and some of the macroscopic and histopathologic features of the lesions differ from previous descriptions of atherosclerosis in psittacine birds.

A 1-year old, male canary (Serinus canaria) with a history of an enlarged abdomen of several days duration died acutely and was submitted for necropsy. Results revealed a yellow to tan hard mass, 2 cm in diameter, adherent to the cloacal wall. Histologically, the mass was composed of interlacing bundles of pleomorphic spindle cells with numerous and bizarre mitotic figures. Neoplastic cells were positive for vimentin and negative for desmin and actin and showed ultrastructural features (dilated stacks of rough endoplasmic reticulum, intermediate filaments, rare collagen secretion granules, lack of external lamina) typical of fibroblasts. Based on these results, the diagnosis was cloacal fibrosarcoma, previously not reported in canaries.

A 7-month-old, male eclectus parrot (Eclectus roratus roratus) was presented with a slow-growing mass over the chest and localized self-trauma to the area. Repeated sternal trauma secondary to an improper wing trim was observed in this case before development of the lesion. Surgical excision of the mass was performed for diagnostic and treatment purposes. On histopathologic examination, the mass was characterized by well-differentiated trabecular bone surrounded by a thin layer of periosteum. These findings were consistent with, but not exclusive to, a diagnosis of osteoma. This benign bone lesion is rare in human and veterinary medicine, with even fewer reports of this condition in avian patients. Trauma to the sternum from falling because of wing clipping was the most likely inciting cause in this parrot.

An adult, male double yellow-headed Amazon parrot (Amazona ochrocephala oratrix) was diagnosed with chronic lymphocytic leukemia based on results of a complete blood cell count and cytologic examination of a bone marrow aspirate. Treatment with oral chlorambucil was attempted, but no response was evident after 40 days. The bird was euthanatized, and the diagnosis of chronic lymphocytic leukemia was confirmed on gross and microscopic examination of tissues. Neoplastic lymphocytes were found in the bone marrow, liver, kidney, testes, and blood vessels. Based on CD3-positive immunocytochemical and immunohistochemical immunophenotyping, the chronic lymphocytic leukemia was determined to be of T-cell origin.