title: Effectiveness of a nonpenetrating captive bolt for euthanasia of piglets less than 3 d of age.
abstract: The objective of this study was to determine the effectiveness of a nonpenetrating captive bolt (NPCB), the Zephyr-Euthanasia (Zephyr-E), for euthanasia of neonatal piglets<72 h of age using signs of insensibility and death, as well as postmortem assessment of traumatic brain injury (TBI). The Zephyr-E was used by 10 stock people to euthanize 100 low viability neonatal piglets from 3 commercial farrowing units and 1 research farm. Brainstem reflexes, convulsions, and heartbeat were used to assess insensibility, time of brain death, and cardiac arrest after Zephyr-E application. Hemorrhage severity and skull fracture displacement (FD) were quantified from computed tomography scans (n=10), macroscopic scoring was used to assess brain hemorrhage and skull fracture (SK) severity (n=100), and microscopic scoring was used to assess subdural (SDH) and parenchymal (PH) hemorrhage within specific brain regions that are responsible for consciousness and vital function (n=10). All 100 piglets were rendered immediately insensible without return to sensibility. On average, clonic convulsions (CC) ceased in 101 s (±7.4 SE), brain death was achieved in 229 s (±9.18 SE), and cardiac arrest occurred in 420 s (±13.57 SE). Time of cardiac arrest differed significantly among stock people when either body weight (BW: P=0.0053) or body mass index (BMI: P=0.0059) was used as a covariate. The BMI was inversely related to the duration of CC (P=0.0227). Moderate to severe hemorrhage severity was reported in 9 of 10 piglets. There was no relationship between FD and BW (P=0.8408) or BMI (P=0.6439). Macroscopic analyses indicated moderate to severe hemorrhage and SK in all piglets. No differences were found among brain sections for SDH (P=0.2302); PH was greater in the cerebral cortex than in the midbrain and brainstem (P=0.0328). The Zephyr-E NPCB reliably caused immediate, sustained insensibility followed by death in neonatal piglets. Postmortem assessment confirmed that application of the Zephyr-E caused widespread, irreversible brain damage.
authors.affiliation: Department of Animal and Poultry Science, University of Guelph, ON N1G 2W1, Canada.
authors.forename: T M
authors.initials: TM
authors.lastname: Casey-Trott
authors.forename: S T
authors.initials: ST
authors.lastname: Millman
authors.forename: P V
authors.initials: PV
authors.lastname: Turner
authors.forename: S G
authors.initials: SG
authors.lastname: Nykamp
authors.forename: T M
authors.initials: TM
authors.lastname: Widowski
mesh_terms: D000827:Animal Welfare; D000818:Animals; D000831:Animals, Newborn; D001921:Brain / Q000473:pathology; D001926:Brain Death; D037901:Euthanasia, Animal / Q000379:methods*; D006323:Heart Arrest; D012640:Seizures; D013552:Swine / Q000502:physiology*