Abstract: Technical Note Validation of the effectiveness of electric stunning for euthanasia of mature swine (Sus scrofa domesticus)
Electrocution and use of a penetrating captive bolt gun (PCBG) are both acceptable methods of euthanasia for market weight swine. Research has demonstrated that a PCBG is effective in both growing and mature swine. Given limited to no published research base on electrocution in mature swine, the objectives of the present study were to evaluate the efficacy of a two-stage (head-only followed by head-to-heart, 10 s contact for each) mobile electric stunner (E-STUN, Hubert HAAS TBG 96N) and to assess euthanasia outcomes when comparing E-STUN with frontal placement of a heavy duty PCBG (Jarvis, In-line Cylinder Style) when applied to heavy weight (>200 kg), mature boars and sows. Effectiveness of the E-STUN and PCBG were evaluated first in unconscious anesthetized mature swine (n = 7 boars and sows per treatment; average weight 282 ± 48 kg, n=28) to reduce the risk of failure in a conscious animal and then in conscious mature swine (n = 3 boars and sows per treatment; average weight 282 ± 63 kg, n=12). Data from both stages were combined for analyses. Treatment efficacy was defined as any pig that achieved cardiac and respiratory arrest within 10 min after treatment application. A three-point traumatic brain injury (TBI) score (0 = normal; 1 = some abnormalities; 2 = grossly abnormal, unrecognizable) was used to evaluate six neuroanatomical structures (cerebral cortex, cerebellum, hypothalamus, thalamus, pons, and brain stem), and the presence of intracranial hemorrhage was also noted. All animals were immediately rendered insensible with E-STUN and PCBG and no difference was noted between treatments for detection of corneal reflex following treatment application (P = 0.11). Rhythmic breathing was absent following administration of either E-STUN or PCBG. When evaluating time to last heartbeat, there was a significant interaction between sex and treatment. Boars euthanized via E-STUN had 346.8 s decrease in time to last heartbeat compared to boars euthanized via PCBG (P < 0.001) and females euthanized via E-STUN had a 479.3 s decrease in time to last heartbeat compared to females euthanized via PCBG (P < 0.001). Intracranial hemorrhage was common for both methods and visible disruption of neural tissue was evident due to the physical nature of the PCBG. This study demonstrated that a mobile E-STUN system is as effective as a heavy duty PCBG in inducing insensibility and death and shows promise as an alternative method for euthanizing mature pigs on-farm.
Kramer S, Wagner B, Moeller S, Bowman A, Kieffer J, Arruda A, Cressman M, Pairis-Garcia M. Technical Note Validation of the effectiveness of electric stunning for euthanasia of mature swine (Sus scrofa domesticus). J Anim Sci. 2022 March. https://doi.org/10.1093/jas/skac072