Smith Rebecca K, Rault Jean-Loup, Gates Richard S, Lay Donald C
Department of Animal Sciences, Purdue University, West Lafayette, IN 47907, USA.
Institute of Animal Husbandry and Animal Welfare, University of Veterinary Medicine, A-1210 Vienna, Austria.
Animals (Basel). 2018 Apr 4;8(4):52. doi: 10.3390/ani8040052.
Current methods of euthanizing piglets are raising animal welfare concerns. Our experiment used a novel two-step euthanasia method, using nitrous oxide (N₂O) for six minutes and then carbon dioxide (CO₂) on compromised 0- to 7-day-old piglets. A commercial euthanasia chamber was modified to deliver two euthanasia treatments: the two-step method using N₂O then CO₂ (N₂O treatment) or only CO₂ (CO₂ treatment). In Experiment 1, 18 piglets were individually euthanized. In Experiment 2, 18 groups of four to six piglets were euthanized. In the N₂O treatment, piglets lost posture, indicating the onset of losing consciousness, before going into CO₂ where they showed heavy breathing and open-mouth breathing; whereas piglets in the CO₂ treatment did not lose posture until after exhibiting these behaviors ( ≤ 0.004). However, piglets in the N₂O treatment took longer to lose posture compared to the CO₂ treatment ( < 0.001). Piglets in the N₂O treatment displayed more behavioral signs of stress and aversion: squeals/minute ( = 0.004), escape attempts per pig ( = 0.021), and righting responses per pig ( = 0.084) in a group setting. In these regards, it cannot be concluded that euthanizing piglets for 6 min with N₂O and then CO₂ is more humane than euthanizing with CO₂ alone.
当前的仔猪安乐死方法引发了动物福利方面的担忧。我们的实验采用了一种新颖的两步安乐死方法，对0至7日龄体质较弱的仔猪，先使用一氧化二氮（N₂O）6分钟，然后使用二氧化碳（CO₂）。对一个商用安乐死舱进行了改装，以实施两种安乐死处理：先使用N₂O然后使用CO₂的两步法（N₂O处理）或仅使用CO₂（CO₂处理）。在实验1中，对18头仔猪进行了个体安乐死。在实验2中，对18组每组四至六头仔猪进行了安乐死。在N₂O处理中，仔猪在进入CO₂之前就失去了姿势，这表明开始失去意识，进入CO₂后它们出现了深呼吸和张嘴呼吸；而CO₂处理组的仔猪直到出现这些行为后才失去姿势（≤0.004）。然而，与CO₂处理相比，N₂O处理组的仔猪失去姿势所需的时间更长（<0.001）。在群体环境中，N₂O处理组的仔猪表现出更多的应激和厌恶行为迹象：每分钟尖叫次数（=0.004）、每头猪的逃跑尝试次数（=0.021）和每头猪的翻正反射次数（=0.084）。在这些方面，不能得出先使用N₂O 6分钟然后使用CO₂对仔猪实施安乐死比仅使用CO₂实施安乐死更人道的结论。
