Anaesthesia of three young grey seals (Halichoerus grypus) for fracture repair

Using a combination of midazolam and butorphanol is a safe and effective reversible field sedation protocol for Weddell seal (Leptonychotes weddellii) pups

BACKGROUND

Weddell seals (Leptonychotes weddellii) are a well-studied species of phocid with an apparent sensitivity to immobilising agents. Mortality as high as 31% has been reported during field immobilisation. This study investigated the use of a benzodiazepine in combination with an opioid agonist/antagonist for sedation in Weddell seal pups as part of a physiological study.

METHODS

During the 2017 and 2019 Antarctic pupping seasons, 18 Weddell seal pups were sedated by intramuscular administration of a combination of midazolam and butorphanol or intravenous midazolam alone. Individuals were sedated at 1, 3, 5 and 7 weeks of age. Naltrexone and flumazenil were used to reverse sedation. The combination was 100% effective in providing appropriate sedation for the intended procedures.

RESULTS

Analyses were performed to investigate relationships between dose administered, age, individual reactions, adverse effects and changes in dive physiology. Transient apnoea (10-60 seconds) was the most frequently observed adverse effect. No sedation-associated morbidity or mortality occurred.

LIMITATIONS

The sample size is small and there is no pharmacokinetic information for either sedative or reversal in phocid species.

CONCLUSIONS

The combination of midazolam (0.2-0.3 mg/kg) and butorphanol (0.1-0.2 mg/kg) provided safe and effective sedation, with reversible effects, in Weddell seal pups.

MANDIBULAR FRACTURES IN GIRAFFES (GIRAFFA CAMELOPARDALIS) IN EUROPEAN ZOOS

Following a case of mandibular fracture in a giraffe (Giraffa camelopardalis) at the Budapest Zoo, a survey was conducted across European zoological institutions with the support of the European Association of Zoos and Aquariums Giraffe Ex situ Programme (EAZA Giraffe EEP) to help identify the incidence, potential causes, and management of such injuries. Two hundred sixteen zoos keeping giraffes were invited to participate in the survey. Eighty-six responses were received, 14 of which (16.3%) reported jaw fractures with various causes in their giraffes. Of these responses, hay racks, where the muzzle of the giraffe could fit between the grid of feeding contraptions, were associated with mandibular fractures in seven cases (50.0%). Most giraffes were managed surgically (10/14; 71.4%), two were managed medically (14.3%), one was euthanized because of the severity of the injury (7.1%), and one was only diagnosed with a mandibular fracture postmortem. One giraffe died owing to postanesthetic complications; all other individuals had a full recovery. Most mandible fractures occurred in relatively young giraffes (between 5 wk and 8 yr with an average of 3.4 yr). Based on these findings, facilities with giraffe should evaluate their hay feeders for mandible entrapment risk, especially if they house young individuals.

RETROSPECTIVE STUDY OF SURGICAL TREATMENT OF REFRACTIVE OSTEOMYELITIS AND INFECTIOUS ARTHRITIS IN THE FLIPPERS OF SEALS IN THE NETHERLANDS

Amputation surgery in pinniped rehabilitation centers is a feasible procedure when animals are presented with open fractures, osteomyelitis, and/or infectious arthritis of the flippers that appear to be refractory to medical treatment. From 2011 to 2017, the Sealcentre Pieterburen in The Netherlands admitted 3,775 seals for rehabilitation. Of these, 37 individuals presented clinical and radiologic signs of bone abnormalities indicative of osteomyelitis or infectious arthritis refractory to medical treatment. Seven cases resulted in euthanasia, and 30 cases underwent amputation surgery. The surgical procedure involved amputation of part of a flipper (24; two animals twice) or of a complete flipper (eight). All procedures were done under general anesthesia except one that was performed with local anesthesia, and all 30 animals were released. In two cases, the osteomyelitis presented with the rare Totenlade phenomenon, a sequestrum surrounded by new periosteal bone formation. The purpose of this retrospective study was to evaluate the outcome of the operative treatment of osteomyelitis and infectious arthritis in the flippers of harbor (Phoca vitulina) and grey seals (Halichoerus grypus) during this 6-yr period.

Surgical repair of a tibial fracture in a two-week-old grey seal (Halichoerus grypus)

Objective: To report the successful management of a suspected infected tibial fracture in a common grey seal.

Study design: Case report.

Animal: Female common grey seal (Halichoerus grypus), 2 weeks old, 20 kg.

Methods: A closed, complete, transverse fracture of the left tibial distal diaphysis was debrided, reduced and stabilized using a string-of-pearls (SOP) locking plate covered with polymethylmethacrylate impregnated with gentamicin. Fracture of the ipsilateral fibula was left untreated. Postoperative radiographs were obtained immediately, and at 10 days, three weeks, and six weeks post-surgery, and a computed tomographic examination was performed 2.5 months post-surgery. A species-specific progressive rehabilitation programme was conducted.

Results: Bone healing of both fractures and absence of injury of the distal tibial growth plate were evident on the 2.5 month follow-up examination, and also full range-of-motion of the flipper was preserved and no lameness or difficulty with swimming and hunting were detected. On computed tomography, signs of chronic left coxofemoral and ilial wing trauma were incidentally detected. The seal was released three months postoperatively.

Conclusion: A transverse infected distal fracture of the tibia and fibula in a young common grey seal was successfully managed with the combination of single SOP plating of the tibia, local antibiotic release and a specific rehabilitation programme.

Clinical relevance: Surgical treatment of a long-bone fracture in a wild immature grey seal was successful with a combination of techniques adapted to the species.

Focal bacterial meningitis following ascending bite wound infection leading to paraparesis in a captive California sea lion (Zalophus californianus)

Magnetic resonance imaging was performed on a 15-yr-old captive female California sea lion (Zalophus californianus) with a 2-wk history of progressive paraparesis and a 9-mo history of exudative skin lesion on the left thoracic wall. Magnetic resonance images showed a well-defined muscle infiltrating lesion ventrolateral to the seventh cervical to the third thoracic vertebra on the left side, which extended through the left intervertebral foramina C7 to T3 into the vertebral canal, causing spinal cord compression and displacement as well as inflammation of the spinal cord and nerves. This lesion surprisingly caused no forelimb deficits. Differential diagnoses included abscess formation or neoplasia. Pathologic examination revealed chronic focal purulent meningitis associated with widespread paraspinal fistulous inflammation originating from a chronic dermal ulcer. Mainly Escherichia coli var. haemolytica and Clostridium perfringens were identified as the underlying agents.