Pathophysiology of Concussive Non-Penetrative Captive Bolt Stunning of Turkeys

SIMPLE SUMMARY: For routine slaughter, animals are rendered unconscious prior to the act of slaughter in order to prevent pain and distress. The electrical stunning methods generally used by small-scale seasonal turkey producers can be ineffective in inducing unconsciousness. An alternative method is non-penetrating captive bolt stunning (NPCB) which involves the firing of a mushroom shaped metal rod against the head to induce concussion and unconsciousness. This study evaluated the effectiveness of two models of NPCB guns for inducing unconsciousness in turkeys. Effectiveness was assessed with behavioural responses and the level of induced brain damage. Both NPCB guns used in this study were effective in inducing unconsciousness as assessed with behavioural responses. There was extensive damage throughout all regions of the brain. These results support the use of NPCB stunning as an effective stunning method for commercial slaughter of turkeys when used correctly. ABSTRACT: The non-penetrative captive bolt (NPCB) has been proposed as a more humane and practical alternative to constant voltage electrical stunning for small-scale seasonal turkey producers. This study evaluated the effectiveness of the CASH(®) Small Animal Tool (SAT) (formerly known as the CASH(®) Poultry Killer, CPK) and three configurations of the Turkey Euthanasia Device (TED), assessing behavioural, cranial/spinal responses and brain pathology. Immediately after stunning all birds showed cessation of rhythmic breathing and loss of neck and beak tension. One bird shot with the TED/hen configuration showed a positive nictitating membrane reflex in one eye with no other positive reflexes. All birds had moderate/severe gross damage to the hyperpallium layer over the cerebrums. For almost all other cerebrum structures, thalamus, and hindbrain, the TED/poult configuration and SAT produced the most extensive damage. The frequency of petechial haemorrhage in the pons and medulla was less in SAT shot birds (76% and 71% respectively) compared to those shot with the different configurations of the TED (ranging from 81% to 100%), however this difference was not significant. In conclusion, both NPCB guns were effective in inducing unconsciousness in turkeys, regardless of the variations in shot position and the different configurations of the TED.