Reproductive suppression of giraffe (Giraffa camelopardalis) under managed care using a GnRH immunological product.

Giraffe present unique contraception challenges as males persistently pursue females during estrus. Year-round pursuit during frequent recurring estrus can pose significant risk under slippery conditions. Complete ovarian suppression is a useful tool in giraffe because it eliminates estrous behavior, interest from the male, and controls reproduction. Effective reproduction control in giraffes has been achieved with porcine zona pellucida, oral melengestrol acetate, and depot medroxy-progesterone acetate. However, these methods allow some degree of folliculogenesis and estrous behavior. Improvest® is a gonadotropin releasing hormone (GnRH) immunological product that elicits antibodies against GnRH and abrogates the effects of endogenous GnRH. This study evaluated the efficacy of Improvest® for gonadal suppression in seven females and one male giraffe by monitoring steroid hormones. Seven female giraffe were treated intramuscularly with an initial dose, a booster at 4 weeks and maintenance boosters at 3-month intervals (600 µg/dose) for 12 months. Six females were on supplemental contraception during the induction phase because separation from males was not possible. In the male (treated with 400 µg), testosterone concentrations decreased after the second injection. However, even with low serum testosterone concentrations, mounting (of nontreated females) behavior was still observed occasionally. Ovarian activity was suppressed in all treated females and interest by the males stopped; supplemental contraceptives (during the induction phase) did not impede the effect of Improvest®. After 15.3 months (seven doses), Improvest® was discontinued in three females which no longer needed contraception. In these females, ovarian activity was noted approximately 90 days after the last dose.

PHARMACOKINETICS OF MELOXICAM FOLLOWING A SINGLE ORAL DOSE IN MALAYAN FLYING FOXES ( PTEROPUS VAMPYRUS).

Meloxicam, a COX-2 selective nonsteroidal anti-inflammatory medication, has been used in many exotic animals at doses extrapolated from domestic animal pharmacokinetic and pharmacodynamic studies. Increasing evidence suggests that significant species differences exist in meloxicam metabolism. Because of this, dose extrapolation from domestic animals may not be appropriate for exotic species. The objective of this study was to investigate the pharmacokinetics of meloxicam in a population of male Malayan flying foxes, Pteropus vampyrus, following a single oral dose of 0.2 mg/kg. Using a sparse sampling method based on a pilot study, two blood samples from each of 10 bats were collected over an 8-hr time period. Analysis of meloxicam in plasma samples was conducted using reversed-phase high-performance liquid chromatography. The peak plasma concentration of 598 ± 157.5 ng/ml occurred at 1.0 hr post dosing. The terminal half-life was 1.1 ± 0.1 hr, which indicates that meloxicam is rapidly metabolized in this species. No adverse clinical effects were noted during the study period. A single oral dose of 0.2 mg/kg appears safe for use in male Malayan flying foxes, but due to rapid elimination, frequent dosing may be required to maintain plasma concentrations within a therapeutic range. Multidose studies are needed to determine if plasma accumulation of meloxicam occurs.

DIAGNOSIS AND PALLIATIVE MANAGEMENT OF ATOPIC DERMATITIS IN A MALAYAN FLYING FOX (PTEROPUS VAMPYRUS).

A 7-yr-old male Malayan flying fox (Pteropus vampyrus) presented with chronic, recurrent bilateral conjunctivitis and palpebral chemosis. Variable, temporary response to topical ocular antibiotic-corticosteroid therapy occurred. Histopathology of a conjunctival biopsy was consistent with allergic conjunctivitis. The bat was treated systemically with antihistamines and topically with an ocular antibiotic-corticosteroid combination for acute episodes of conjunctivitis. Pruritus, severe alopecia of the head and neck, and moist dermatitis later developed in conjunction with bilateral conjunctivitis. Cytology and histopathology of affected skin supported a diagnosis of atopic dermatitis. Although the assay was not validated for P. vampyrus, serum immunoglobulin E levels against multiple possible antigens were measured. Acceptable resolution of clinical signs was achieved for 20 mo following systemic cyclosporine administration. Cyclosporine levels were measured in whole blood for additional therapeutic monitoring. This is the first reported case of histopathologic support for atopic dermatitis, novel diagnostics, and palliative management of atopy using cyclosporine in a flying fox.

Squamous cell carcinoma of the anal sac in a spotted hyena (Crocuta crocuta).

A 25-yr-old spayed female spotted hyena (Crocuta crocuta) developed intermittent right pelvic limb lameness that persisted following conservative medical therapy. No obvious musculoskeletal lesions were noted on initial physical exam; however, spinal radiography was suspicious for possible intervertebral degenerative joint disease or discospondylitis. Despite prolonged medical therapy, the lameness progressed to minimal weight bearing and marked muscle atrophy of the right pelvic limb. Electromyography showed spontaneous activity in the muscles of right sciatic nerve distribution. Sensory and motor nerve conduction velocities in the right tibial and peroneal nerves were undetectable and markedly reduced, respectively. A magnetic resonance imaging (MRI) scan revealed a large, space-occupying mass on the right side of the sacrum and pelvis. Antemortem fine-needle aspiration of the mass and postmortem histopathology resulted in diagnosis of a high-grade squamous cell carcinoma of the anal sac. Squamous cell carcinoma of the anal sac is very rare in domestic dogs and previously unreported in spotted hyenas.

Diagnosis and treatment of primary hyperparathyroidism in a bobcat (Lynx rufus).

An 18-yr-old male bobcat (Lynx rufus) presented with chronic moderate weight loss and acute onset of anorexia and lethargy. Hypercalcemia and azotemia were present on the serum chemistry panel. Abdominal ultrasound revealed hyperechoic renal cortices, but no evidence of neoplasia. Ionized calcium and 25-hydroxyvitamin D were mildly elevated, intact parathyroid hormone was severely elevated, and parathormone-related protein was undetected, suggesting primary hyperparathyroidism with possible renal dysfunction. Azotemia lessened in severity following diuresis, but hypercalcemia persisted; thus primary hyperparathyroidism was considered the most probable differential diagnosis. A second ultrasound including the cervical region revealed a solitary intraparenchymal left thyroid nodule. The nodule was surgically excised; histopathology confirmed a parathyroid adenoma. Although primary hyperparathyroidism was suspected, diagnosis was not achieved from serum chemistry values alone. This case emphasizes the importance of diagnostic imaging and histopathology in the investigation of persistently abnormal laboratory values.

Chemotherapy and radiotherapy for treatment of cutaneous lymphoma in a ground cuscus (Phalanger gymnotis).

A 15-year-old female ground cuscus (Phalanger gymnotis) was presented with an isolated ulcerated, nonhealing lesion on the lateral thorax. Histopathology and immunohistochemistry were diagnostic for cutaneous T-cell lymphoma with incomplete excision. Oral chemotherapy with CCNU (lomustine) resulted in clinical remission that lasted 255 days, with no appreciable toxicity. Tumor recurrence was treated with radiation therapy, which resulted in 120 additional days of clinical remission. Subsequently, the tumor developed at a distant site and the cuscus was humanely euthanized. A slight decrease in appetite early in disease progression was the only adverse effect noted throughout the treatment period. Oral, minimally invasive chemotherapy, and adjunct radiation therapy were viable treatment options for this ground cuscus and should be considered for treatment of neoplasia in other nontraditional species.

Clostridium piliforme encephalitis in a weaver bird (Ploceus castaneiceps).

A juvenile Taveta golden weaver (Ploceus castaneiceps) bird housed in a zoo aviary developed a sudden onset of neurological signs. The bird demonstrated head tilt, rolling onto its back, and inability to perch. Euthanasia was elected due to lack of response to intensive care, and a necropsy was performed. There were no significant abnormal findings on gross examination. On histopathology, the remarkable findings were localized to the brain and consisted of multifocal cerebral microabscesses and rarefaction. Filamentous rod-shaped bacteria were present within and at the periphery of the necrotic foci, and dispersed throughout the neuroparenchyma and intracellularly in neurons. The bacteria were Gram negative, and Warthin-Starry stain demonstrated characteristic "hay stacking." Real-time polymerase chain reaction analysis of the brain identified the agent as Clostridium piliforme. An additional microscopic finding was severe crypt enteritis; however, the bacteria were not observed in the intestinal sections.