Abstract:
According to animal welfare concern, the aim of any killing technique is to achieve
rapid loss of sensibility to cause minimal pain in animals. This study assessed the
efficacy of novel Koechner Euthanasia Device Model-S (KED) in comparison to
manual cervical dislocation in anesthetized layer chicks (2-3 day old). Due to ethical
concern, novel killing devices are tested in anesthetized animals. Thus,16 chicks
(Avg BW ± SD; 44 ± 3 g, Shaver White, ISA Brown and Lohman Select Leghornlite) were randomly assigned to the two experimental groups: manual cervical
dislocation in anesthetized chicks or mechanical cervical dislocation by KED in
anesthetized chicks(n=8). Generalized linear mixed model (GLMM) by using SAS
9.4 version was used to analyze the antemortem measurements. Longer time to lose
the pupillary light reflex (94.4 ± 7s, P=0.09) and cessation of heartbeat (196.4±15s,
P=0.03) was observed in the chicks killed by KED in comparison to the other group
(66.6 ± 9s and 138.5 ± 18s respectively). Radiographs assessment reported that
manual cervical dislocation resulted in cervical dislocations below the C4 vertebra.
The ideal dislocation of skull to C1 was absent in both the killing method. Few chicks
killed by manual cervical dislocation exhibited cervical fractures. Cervical
dislocations and fractures were not observed in the chicks killed by KED. Higher
scores for the subdural hemorrhage at the site of cervical dislocation was observed
in the chicks killed by manual cervical dislocation whereas it was minimum for the
chicks killed by KED. Brain trauma was absent in both the methods. Based on time
to brain death and anatomical pathology, KED resulted in lower efficacy in
comparison to manual cervical dislocation as on-fam euthanasia method for 2-3-day
old layer chicks.
