Journal Articles

Permanent URI for this collectionhttps://mro.massey.ac.nz/handle/10179/7915

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    Using post-mortem computed tomography to identify traumatic cranial lesions in small stranded odontocetes euthanised via ballistics
    (Taylor and Francis Group on behalf of the New Zealand Veterinary Association, 2025-07-29) Boys RM; Stewart RO; Kot BCW; Lye G; Beausoleil NJ; Stockin KA
    Aims: To describe the pathophysiology caused by ballistics applied to the head of stranded cetaceans that required euthanasia and use this information to infer the likely welfare implications of these real-life euthanasia events. Methods: Post-mortem computed tomography (PMCT) imaging was conducted on six cetacean carcasses of five different species that were submitted for dissection following ballistics euthanasia. No animals were euthanised for the purpose of this study. All data were collected opportunistically at stranding events where euthanasia was a priori deemed necessary by the Department of Conservation (DOC) in partnership with indigenous Māori (iwi). The cranial damage assessed included osseous lesions at entry and exit wounds, intracranial bone fractures and intracranial projectile fragments. Potential welfare implications were inferred based on the likelihood of instantaneous insensibility occurring due to direct physical disruption to the brainstem. Additionally, basic stranding data were collected from DOC incident reports including whether animals were refloated prior to the decision for euthanasia. We also gathered information from the marksperson involved on how the ballistics method was employed, equipment used, and animal insensibility assessed at each stranding event. Results: PMCT results suggest that two animals were likely instantaneously insensible, three had a moderate chance of being instantly insensible and one had a low chance of instantaneous insensibility. In one case, the marksperson reported a faster time to insensibility/death than was judged likely to have occurred from PMCT. In only two cases were the criteria for verifying insensibility reported as being checked. The likelihood of instantaneous insensibility occurring was affected by shot placement/aim and characteristics of the projectile used. Conclusions: Euthanasia is a critical option for severely compromised cetaceans. While most animals examined were probably rapidly insensible following shooting, cranial trauma and thus confidence in the efficacy of ballistics seemed to vary with shot placement, aim, equipment and cranial anatomy. Clinical relevance: Verification of insensibility immediately following shooting, by assessing reflex responses as recommended, is crucial to ensure humane emergency management. PMCT provides an effective non-destructive tool to validate field methods for assessing the efficacy of euthanasia.
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    Ethological and procedural assessment of ballistics euthanasia for stranded cetaceans
    (Elsevier B.V., 2025-02-12) Boys RM; Beausoleil NJ; Stockin KA
    Euthanasia may be necessary at cetacean stranding events to end suffering. To ensure a humane death, verification of unconsciousness must be undertaken following application of the killing method. However, only limited information is reported on individual euthanasia events, including how unconsciousness and/or death is assessed. Here, we describe current practices for euthanising stranded cetaceans in New Zealand by analysing video footage of fourteen ballistics events involving various species. Specifically, we detail the ballistics procedures applied and the behavioural responses of the animals. Additionally, we sought to understand how animal unconsciousness was evaluated following each event by surveying the personnel involved. Video recordings ranged in length from 25 to 480 s after the initial shot and involved 14 cetaceans: one Cuvier's beaked whale, one pygmy sperm whale, one bottlenose dolphin, four pilot whales and seven false killer whales. Unconsciousness criteria were typically not observed being verified in the videos analysed, despite markspersons stating that death occurred in < 1 minute for most animals. Number of shots applied to an animal ranged from 1–3. Key behaviours indicative of unconsciousness included a continuously slack lower jaw and epaxial muscle relaxation. Based on behavioural observations, 66.7 % of animals for which an estimate could be made (n = 12) were likely unconscious within 30 s of the initial shot; half of these were likely unconscious within 10 s. The remaining animals appeared conscious for 30 s after the initial shot, and half of these were likely still conscious after one minute. Ten animals displayed post-shot behaviours suggestive of voluntary control, including tail lifting, beyond the point of presumed death reported by markspersons. The lack of verification of unconsciousness in most animals (12/14) hinders our ability to understand how these behaviours may correlate with awareness and thus welfare impacts of shooting. While the application of ballistics appeared to follow current national recommendations, mandated procedures for verifying death were rarely observed. We recommend exploring the reasons for this finding, to ensure that such procedures are appropriately undertaken, and welfare compromise minimised.