ABSTRACT

1. Moribund or diseased poultry requiring euthanasia are often dehydrated. To understand how dehydration influences the efficacy of various killing methods, this experiment investigated the effect of water deprivation (WD) on times to unconsciousness and death.

2. Broiler chickens (n = 179) were water-deprived for 0, 24, 48 or 72 hours to mimic dehydration, then killed via manual cervical dislocation, mechanical cervical dislocation (Koechner Euthanising Device (KED)), or non-penetrating captive bolt (Zephyr-EXL), at 8, 22, 36 or 50 d of age. Degree of WD was confirmed by skin turgor, packed cell volume and body weight loss. Method efficacy was evaluated by the time to unconsciousness and death using pupillary light (PUP), palpebral blink (PAL) and nictitating membrane (NIC) reflexes, feather erection (FE), cloacal winking (CW) and convulsions (CN). The extent of damage caused by each method was examined via radiography, gross pathology and histopathology. The main effects of WD time and euthanasia method were analysed by two-way analyses of variance (CRD, PROC MIXED, SAS 9.4) with a-priori contrasts to compare water-deprived versus non-water-deprived (NON) birds.

3. Skin turgor, packed cell volume and body weight loss had a quadratic relationship with WD, with highest values for those birds which were water-deprived for 72 h. WD level did not affect time to unconsciousness. Time to death was longer for WD birds than NON, with longer latencies to FE, CW and CN for water-deprived birds. WD only affected radiography or gross pathology scores on d 8, with the extent of subcutaneous haemorrhage within the neck decreasing as WD increased.

4. The shortest latency to PUP loss, at all ages, and to PAL and NIC loss, at 22 d, was with the Zephyr-EXL. KED had the longest time to unconsciousness (PUP, PAL and NIC), at all ages, and to death, at 36 and 50 d.

5. Overall, WD increased time to death, but did not affect the onset of unconsciousness, with no interaction between methods and WD level.

抽象的

1.需安乐死的垂死家禽或患病家禽通常会脱水。为了了解脱水如何影响各种杀灭方法的功效，本实验研究了缺水（WD）对失去知觉和死亡时间的影响。

2.将肉鸡（n = 179）缺水0、24、48或72小时以模拟脱水，然后通过手动颈脱位，机械颈脱位（Koechner Euthanising Device（KED））或非穿透性圈养将其杀死螺栓（Zephyr-EXL），使用寿命为8、22、36或50天。WD的程度通过皮肤的充盈，细胞的堆积和体重的减少来确定。通过使用瞳孔灯（PUP），睑闪烁（PAL）和神经膜反射（NIC）反射，羽毛勃起（FE），泄殖腔眨眼（CW）和抽搐（CN）的昏迷和死亡时间评估方法的有效性。由每个方法破坏的程度进行了检查通过射线照相，肉眼病理学和组织病理学。通过双向方差分析（CRD，PROC MIXED，SAS 9.4）分析了WD时间和安乐死方法的主要影响，并先验比较了缺水和非缺水（NON）禽。

3.皮肤充血，细胞堆积量和体重减轻与WD呈二次关系，缺水72 h的鸟类的最高值。WD水平不会影响失去知觉的时间。WD禽类的死亡时间比NON更长，缺水禽类的FE，CW和CN潜伏期更长。WD仅在第8天影响放射线照相或总体病理学评分，随着WD的增加，颈部皮下出血的程度降低。

4.使用Zephyr-EXL可以使所有年龄段的PUP丢失以及PAL和NIC丢失的最短延迟时间为22天。在所有年龄段，KED失去知觉（PUP，PAL和NIC）的时间最长，在死亡36和50 d时，死亡的时间最长。

5.总体而言，WD增加了死亡时间，但不影响意识丧失的发作，方法与WD水平之间没有相互作用。