Mycoplasma corogypsi-associated polyarthritis and tenosynovitis in black vultures (Coragyps atratus)

Three wild American black vultures (Coragyps atratus) were presented to rehabilitation centers with swelling of multiple joints, including elbows, stifles, hocks, and carpal joints, and of the gastrocnemius tendons. Cytological examination of the joint fluid exudate indicated heterophilic arthritis. Radiographic examination in 2 vultures demonstrated periarticular soft tissue swelling in both birds and irregular articular surfaces with subchondral bone erosion in both elbows in 1 bird. Prolonged antibiotic therapy administered in 2 birds did not improve the clinical signs. Necropsy and histological examination demonstrated a chronic lymphoplasmacytic arthritis involving multiple joints and gastrocnemius tenosynovitis. Articular lesions varied in severity and ranged from moderate synovitis and cartilage erosion and fibrillation to severe synovitis, diffuse cartilage ulceration, subchondral bone loss and/or sclerosis, pannus, synovial cysts, and epiphyseal osteomyelitis. No walled bacteria were observed or isolated from the joints. However, mycoplasmas polymerase chain reactions were positive in at least 1 affected joint from each bird. Mycoplasmas were isolated from joints of 1 vulture that did not receive antibiotic therapy. Sequencing of 16S rRNA gene amplicons from joint samples and the mycoplasma isolate identified Mycoplasma corogypsi in 2 vultures and was suggestive in the third vulture. Mycoplasma corogypsi identification was confirmed by sequencing the 16S-23S intergenic spacer region of mycoplasma isolates. This report provides further evidence that M. corogypsi is a likely cause of arthritis and tenosynovitis in American black vultures. Cases of arthritis and tenosynovitis in New World vultures should be investigated for presence of Mycoplasma spp, especially M. corogypsi.

Combined hepatocellular-cholangiocarcinoma in a lesser flamingo (Phoenicopterus minor)

A case of combined hepatocellular-cholangiocarcinoma (CHCC) in an adult male lesser flamingo (Phoenicopterus minor) that was part of a breeding programme at a private facility is reported. Grossly, the liver was markedly enlarged with multifocal, well-circumscribed, pinpoint to 2 cm diameter pale tan nodular masses. Histologically, the hepatic parenchyma was replaced by neoplastic cells that demonstrated hepatocellular and, less frequently, biliary epithelial cell differentiation. Positive pan-cytokeratin (AE1/AE3/PCK26) immunolabelling of the neoplastic cells forming bile ducts with the scattered immunoreactivity of cells forming glandular structures within the areas of hepatocellular differentiation supported the diagnosis. No metastases were detected. CHCC is a rare neoplasm in mammals and birds. This is the first report where gross, histological, and immunohistochemical characteristics of CHCC in a bird are described, and the first report of CHCC in a lesser flamingo.

Intermittent biotelemetric monitoring of electrocardiograms and temperature in male broilers at risk for sudden death syndrome

Biotelemetry was used to acquire electrocardiograms (ECG) and temperature measurements in a study of male broilers at risk for sudden death syndrome (SDS), a fatal condition that may have underlying cardiovascular mechanisms. Day-old (Day 1) Arbor Acres x Arbor Acres male chicks were randomly assigned to two different diets: control (Diet A) and one that contained elements that contribute to SDS (Diet B). The heaviest birds in each group on Day 13 underwent surgery on Day 15 to have transmitters with temperature sensors and ECG electrodes implanted. After surgery, three controls and three implanted birds from each diet group were kept in individual cages and exposed to 23 h of light and 1 h of darkness during each 24-h cycle. Implantation did not affect weight gain between Days 13 and 22 (P = 0.396). Temperature measurements and 1-min ECG were taken every 15 min. Heart rate and heart rate variability were measured from three 2-s segments in two dark and two light period samples during Days 17 to 19. Diet B decreased weight gain (P = 0.045), lowered heart rate (P < 0.0001), and increased internal temperature (P < 0.0001). Heart rate variability was lower during dark versus light periods (P = 0.004), which indicates that the birds rested during the dark periods, but was not affected by diet (P = 0.651). Thus, biotelemetry provided a useful method for intermittent physiological monitoring of poultry on different diets and under changing environmental conditions.

Capnographic monitoring of anesthetized African grey parrots receiving intermittent positive pressure ventilation

OBJECTIVE

To determine whether end-tidal partial pressure of carbon dioxide (PETCO2) correlated with PaCO2 in isoflurane-anesthetized African grey parrots receiving intermittent positive pressure ventilation (IPPV).

DESIGN

Prospective study.

ANIMALS

14 healthy mature African grey parrots (Psittacus erithacus timnus).

PROCEDURE

Each bird was anesthetized via mask with isoflurane, intubated, and connected to a pressure-limited intermittent-flow ventilator. Respiratory rate was altered while holding peak inspiratory pressure constant (5 cm H2O) to achieve a PETCO2 in 1 of 3 ranges: < 30 mm Hg, 30 to 40 mm Hg, and > 40 mm Hg. Blood was collected from the superficial ulnar artery of each bird at least once during each of the 3 ranges. Arterial blood samples were collected for blood gas analysis while PETCO2 was recorded simultaneously.

RESULTS

A strong correlation between PETCO2 and PaCO2 was detected over a wide range of partial pressures, although PETCO2 consistently overestimated PaCO2 by approximately 5 mm Hg. End-tidal partial pressure of CO2 and PaCO2 also correlated well with arterial blood pH, and the acute response of the bicarbonate buffer system to changes in ventilation was similar to that of mammals.

CONCLUSIONS AND CLINICAL RELEVANCE

Results indicated that PETCO2 reliably estimates PaCO2 in isoflurane-anesthetized African grey parrots receiving IPPV and suggest that IPPV combined with capnography is a viable option for anesthetic maintenance in avian anesthesia.

Holding power of different pin designs and pin insertion methods in avian cortical bone

OBJECTIVE

To measure pullout strength of four pin types in avian humeri and tibiotarsi bones and to compare slow-speed power and hand insertion methods.

STUDY DESIGN

Axial pin extraction was measured in vitro in avian bones.

ANIMAL POPULATION

Four cadaver red-tailed hawks and 12 live red-tailed hawks.

METHODS

The pullout strength of four fixator pin designs was measured: smooth, negative profile threaded pins engaging one or two cortices and positive profile threaded pins. Part 1: Pins were placed in humeri and tibiotarsi after soft tissue removal. Part 2: Pins were placed in tibiotarsi in anesthetized hawks using slow-speed power or hand insertion.

RESULTS

All threaded pins, regardless of pin design, had greater pullout strength than smooth pins in all parts of the study (P < .0001). The cortices of tibiotarsi were thicker than the cortices of humeri (P < .0001). There were few differences in pin pullout strengths between threaded pin types within or between bone groups. There were no differences between the pullout strength of pins placed by slow-speed power or by hand.

CONCLUSIONS

There is little advantage of one threaded pin type over another in avian humeri and tibiotarsi using currently available pin designs. There were few differences in pin pullout strengths between humeri and tibiotarsi bones. It is possible that the case of hand insertion in thin cortices minimizes the potential for wobbling and therefore minimizes the difference between slow-speed drill and hand insertion methods.

CLINICAL RELEVANCE

Threaded pins have superior bone holding strength in avian cortices and may be beneficial for use with external fixation devices in birds.

Axillary cystadenocarcinoma in a Moluccan cockatoo (Cacatua moluccensis)

An adult Moluccan cockatoo (Cacatua moluccensis) was diagnosed with a cystadenocarcinoma in the right axillary region that was treated symptomatically with surgical debulking and periodic drainage. The bird eventually died and a necropsy was performed. The neoplasm extended through the humerus, and small neoplastic foci were seen within the ipsilateral lung parenchyma. Rare groupings of microvilli were observed lining intercellular canalicular lumens on electron microscopy within the axillary tumor. These findings suggest a respiratory neoplasm, although the tissue of origin remained undetermined.

Exocrine pancreatic insufficiency in a yellow-naped Amazon (Amazona ochrocephala) with pancreatic adenocarcinoma

This report describes exocrine pancreatic insufficiency in a yellow-naped Amazon (Amazona ochrocephala) with complete effacement of the pancreas by a pancreatic adenocarcinoma. The bird presented with a 3-month history of weight loss and voluminous, foul-smelling droppings. Clinically, routine hematologic findings were normal and fecal tests were performed to evaluate exocrine pancreatic function. The fecal function tests were positive for neutral and split fats and negative for trypsin. Oral administration of corn oil did not result in elevation of blood triglyceride levels. Two days later, the triglyceride tolerance test was repeated using corn oil mixed with pancreatic enzymes. This time, there was a 70% elevation of blood triglyceride levels. Because of a poor prognosis, the bird was euthanatized. At necropsy, the pancreas was diffusely enlarged, white, nodular, and firm. The liver contained multiple, 1-2-mm-diameter, randomly located, tan nodules. Microscopically, the pancreas was effaced by numerous lobules of neoplastic ductular structures surrounded by abundant fibrous connective tissue. In the liver, the hepatic parenchyma was replaced by multiple, well-demarcated, nonencapsulated foci of neoplastic tissue similar to that in the pancreas.

Ketamine-xylazine anesthesia in red-tailed hawks with antagonism by yohimbine

Five red-tailed hawks (Buteo jamaicensis) were anesthetized at weekly intervals with intravenous ketamine hydrochloride (KET, 4.4 mg/kg) and xylazine hydrochloride (XYL, 2.2 mg/kg). Twenty min after anesthesia, yohimbine hydrochloride (YOH, 0.05, 0.10, 0.20 and 0.40 mg/kg) or a control was administered. All doses of YOH significantly reduced the head-up times (F = 20.84, df = 1,24, P less than 0.0001) and the standing times (F = 12.30, df = 1,24, P less than 0.0001), compared to the control group. The heart and respiratory rates following YOH (all doses) were significantly greater (P less than 0.01) than the anesthetized rates, but were comparable to the rates observed in restrained, unanesthetized hawks. Yohimbine did not appear to have any significant effect on body temperature. Based upon administration of 4.4 mg/kg KET and 2.2 mg/kg XYL, a dose of 0.10 mg/kg YOH was recommended to achieve antagonism without causing profound cardiovascular or respiratory changes.

Chemical denervation of the myenteric plexus of the muscular stomach of turkeys

1. The thin caudoventral muscle (TCM) of the muscular stomach of domestic turkeys was surgically exposed and painted with solutions of saline or 0.1, 0.25, 0.5, and 1.0% benzalkonium chloride (BC), a cationic surfactant shown to irreversibly damage neurons but not muscle tissue in mammals. 2. Following fluoroscopic observations of gastric motility for 2 weeks, turkeys were euthanized, the entire muscular stomach was excised and weighed, and serial frozen sections of the TCM were taken for evaluation of the number and size of neurons in the myenteric plexus. 3. Treatment with 0.5 and 1.0% BC resulted in loss of motility in the TCM, significant hypertrophy (P less than 0.001) of the CTM, a 70% decrease in number and 60% decrease in size of myenteric neurons, and a 4-fold increase in thickness of the serosa, compared with saline-treated controls.