Surgical resolution of an ectopic pregnancy in a captive gerenuk (Litocranius walleri walleri)

A full-term ectopic pregnancy was diagnosed in a multiparous, captive gerenuk (Litocranius walleri walleri) following prolonged gestation without parturition. Until 213 days of gestation, fetal viability was determined by transabdominal ultrasound of fetal heartbeat, physical palpation, and visual observations of fetal movements. Survey abdominal radiographs obtained at day 229 of gestation revealed a fully mineralized fetal skeleton in an inappropriate position for parturition. Surgical exploration revealed a full-term, nonviable, male calf contained within fetal membranes attached to the omentum. Histologic examination of the fetal membranes identified lesions compatible with placenta-cotyledon separation occurring prior to surgical removal. No congenital fetal abnormalities or infectious processes were identified. Visual observation of the reproductive tract at the time of surgery revealed no abnormalities or evidence of concurrent pregnancy.

Intestinal volvulus and stricture associated with a leiomyoma in a green turtle (Chelonia mydas)

A previously stranded 30-kg female green turtle (Chelonia mydas) was referred to the Veterinary Medical Teaching Hospital at the University of Florida following a 2-mo history of anorexia, intermittent regurgitation, decreased fecal production, and positive buoyancy of the right side. Radiographs confirmed gaseous distension of bowel loops suggestive of intestinal obstruction. The coelom was surgically approached through a plastron osteotomy, and a 540 degrees volvulus of the small intestine was identified and derotated. An intestinal stricture was present at the site of the volvulus, and segments of bowel orad to the stricture were greatly distended. Following resection of abnormal bowel, the osteotomy was stabilized using self-tapping screws and figure-eight wire, and the defect was sealed with fiberglass cloth and fast-drying epoxy resin. A leiomyoma associated with the focal stricture was identified by histology. Appetite and defecation returned to normal. Six months after surgery, the turtle had regained normal buoyancy and showed no further clinical signs of gastrointestinal obstruction.

Peripheral neuropathy in a turkey vulture with lead toxicosis

Clinical, electromyographic, and pathologic findings characteristic of lead toxicosis were detected in a turkey vulture (Cathartes aura). The bird had generalized lower motor neuron dysfunction that progressed over 5 days. Electromyography revealed diffuse denervation potentials and a presumed decrement in the sciatic-tibial nerve conduction velocity. Histologic examination of peripheral nerves obtained at necropsy revealed changes that could be compatible with lead-induced neuropathy. Lead toxicosis was confirmed by determination of blood lead concentrations. Lead toxicosis causing neurologic disorders in birds has been described. However, this report emphasizes the effects of lead on the peripheral nervous system and demonstrates the use of electromyography for diagnosis of peripheral neuropathy in birds.

Disposition of single-dose intravenously administered amikacin in emus (Dromaius novaehollandiae)

The pharmacokinetics of amikacin in emus (Dromaius novaehollandiae) was examined following parenteral administration. A mean 7.2 +/- 0.12 mg/kg dose was administered as a single i.v. bolus, and serum samples were collected at predetermined intervals over a 24-hr period. Amikacin levels were measured using a fluorescence polarization immunoassay, and the resulting concentration-versus-time curve was analyzed using nonlinear regression with least squares parameter estimation. The data were best represented by a three-compartment model with a mean elimination half-life (t1/2 beta) of 0.87 hr, with a longer rate of elimination from the third compartment (t1/2 gamma = 6.06 hr). Mean model-independent parameters obtained were area under the curve (269.66 micrograms.hr/ml), mean residence time (6.48 hr), apparent volume of distribution (0.18 L/kg), and total body drug clearance (0.03 L/hr/kg). Mean serum concentrations exceeded a target peak of 32.0 micrograms/ml and remained above an estimated inhibitory concentration of 8.0 micrograms/ml for approximately 12 hr. Mean serum levels had declined below a target trough of 4 micrograms/ml at 24 hr.

Pharmacokinetics of a single intravenous enrofloxacin dose in scimitar-horned oryx (Oryx dammah)

Based on a 1.3 mg/kg mean dosage determined by metabolic energy scaling, enrofloxacin pharmacokinetics of a single i.v. dose of enrofloxacin in five adult scimitar-horned oryx (Oryx dammah) were determined. Drug concentration versus time curves were best fit by residual analysis to a one-compartment open model with a maximum (mean +/- SD) serum concentration after distribution of 1.887 +/- 0.632 micrograms/ml and an elimination half-life of 41.2 +/- 27.5 min. Model-independent parameters were area under the curve (173.63 +/- 147.5 micrograms.min/ml), mean volume of distribution (steady state) (0.80 +/- 0.30 L/kg), clearance (12.07 +/- 7.12 ml/min/kg), and residence time (77.22 +/- 72.8 min). Mean serum enrofloxacin concentrations reached the recommended minimum inhibitory concentration (1.0 micrograms/ml). Drug concentrations remained above the minimum inhibitory concentration of most sensitive bacteria (0.5 micrograms/ml) consistently for 90 min. Based on this study, enrofloxacin would have to be administered parenterally to scimitar-horned oryx at 1.6 mg/kg every 6-8 hr (minimally) to maintain appropriate serum concentrations against susceptible bacteria. The metabolic energy scaled dosed regiment from this study appeared to be too low for the oryx.

Disposition of single-dose intravenously administered enrofloxacin in emus (Dromaius novaehollandiae)

The pharmacokinetics of enrofloxacin in emus (Dromaius novaehollandiae) were examined following parenteral administration. A mean allometrically scaled dose of 2.2 +/- 0.03 mg/kg was administered as a single i.v. bolus, and serum samples were collected at predetermined intervals over a 24-hr period. Enrofloxacin levels were measured using high-performance liquid chromatography, and the resulting concentration versus time curve was analyzed using nonlinear regression with least squares parameter estimation. The data were best represented by a two-compartment model with a mean elimination half-life of 3.33 hr. Mean model independent parameters obtained were area under the curve (8.26 micrograms.hr/ml), mean residence time (4.40 hr), apparent volume of distribution (1.49 L/kg), and total body drug clearance (0.36 L/hr/kg). Mean serum concentrations exceeded the target peak of 2.0 micrograms/ml and remained above an estimated inhibitory concentration of 0.5 micrograms/ml for approximately 2 hr. Based upon the results of this study, enrofloxacin administered parenterally to emus at 2.2 mg/kg every 12 hr is expected to achieve therapeutic serum concentrations against susceptible organisms.