ABSTRACT

1. There is a need to humanely kill moribund or injured broiler birds on-farm with no reasonable chance of recovery. Two experiments evaluated the efficacy of three commercially applicable killing methods; manual cervical dislocation (CD), mechanical cervical dislocation with the Koechner Euthanising Device (KED) and a non-penetrative captive bolt device (Zephyr-EXL; ZEXL), at 7, 21 or 35 d of age, on their ability to induce insensibility (unconsciousness and loss of brain stem reflexes) and death.

2. Experiment one assessed the damage to the cranial-cervical region resulting from the methods applied to cadavers of cull birds (n = 180) by radiography and gross pathology observation.

3. Experiment two evaluated the latency to insensibility and death when cull broiler birds (n = 240) were killed by CD, KED or ZEXL, using behavioural and reflexive indicators. Insensibility and death were measured by the absence of pupillary light, palpebral blink and nictitating membrane reflexes and cessation of rhythmic breathing, cloacal winking and convulsions. Analysis of variance for the main effect of the method was performed to determine the differences.

4. In experiment one, only the Zephyr resulted in skull fractures. A higher number of vertebral fractures occurred with KED application compared to CD, at 21 and 35 d.

5. In experiment two, indicators of sensibility were absent earliest with the ZEXL (μ < 2 s); then,CD (μ = 28 s) and were longest with KED (μ = 47 s), at 21 and 35 d. Cloacal winking and convulsions ceased earlier after CD (88 s), compared to either KED (124 s) or Zephyr (118 s). Death after a single application occurred 100%, 100% and 98% of time for CD, KED and ZEXL, respectively.

6. Overall, all methods were efficacious at inducing insensibility and death. Insensibility occurred earliest with ZEXL, whilst death occurred earliest with CD. KED resulted in the longest time to insensibility and death.

摘要

1. 需要人道地杀死农场中垂死或受伤的肉鸡，而没有合理的康复机会。两项实验评估了三种商业上适用的杀灭方法的功效；手动颈椎脱位 (CD)、使用 Koechner 安乐死装置 (KED) 和非穿透性栓塞装置 (Zephyr-EXL; ZEXL) 的机械颈椎脱位，在 7、21 或 35 日龄时，观察其诱发麻木的能力（无意识和脑干反射丧失）和死亡。

2. 实验一通过射线照相和大体病理学观察评估了应用于扑杀鸟类（n = 180）尸体的方法对颅颈区域的损伤。

3. 实验二使用行为和反射指标评估了当淘汰肉鸡（n = 240）被 CD、KED 或 ZEXL 杀死时的迟钝和死亡潜伏期。通过瞳孔光消失、眼睑眨眼和瞬膜反射以及有节奏的呼吸停止、泄殖腔眨眼和抽搐来衡量麻木不仁和死亡。对方法的主效应进行方差分析以确定差异。

4. 在实验一中，只有 Zephyr 导致颅骨骨折。与 CD 相比，在 21 天和 35 天，使用 KED 发生更多的椎骨骨折。

5、实验二中，ZEXL最早出现感性指标（μ < 2 s）；然后，CD (μ = 28 s) 和 KED (μ = 47 s) 最长，分别为 21 和 35 天。与 KED（124 秒）或 Zephyr（118 秒）相比，泄殖腔眨眼和抽搐在 CD（88 秒）后更早停止。对于 CD、KED 和 ZEXL，单次应用后死亡的发生率分别为 100%、100% 和 98%。

6. 总体而言，所有方法均能有效诱导麻木和死亡。ZEXL 最早发生麻木，而 CD 最早发生死亡。KED 导致了最长的麻木和死亡时间。