Mellor David J
Animal Welfare Science and Bioethics Centre, School of Veterinary Science, Massey University, Palmerston North 4474, New Zealand.
Animals (Basel). 2018 May 31;8(6):82. doi: 10.3390/ani8060082.
Laws, regulations and professional standards increasingly aim to ban or restrict non-therapeutic tail docking in canine puppies. These constraints have usually been justified by reference to loss of tail participation in communication between dogs, the acute pain presumed to be caused during docking itself, subsequent experiences of chronic pain and heightened pain sensitivity, and the occurrence of other complications. These areas are reconsidered here. First, a scientifically robust examination of the dynamic functional foundations, sensory components and key features of body language that are integral to canine communication shows that the role of the tail has been greatly underestimated. More specifically, it shows that tail behaviour is so embedded in canine communication that docking can markedly impede unambiguous interactions between different dogs and between dogs and people. These interactions include the expression of wide ranges of both negative and positive emotions, moods and intentions that are of daily significance for dog welfare. Moreover, all docked dogs may experience these impediments throughout their lives, which challenges assertions by opponents to such bans or restrictions that the tail is a dispensable appendage. Second, and in contrast, a re-examination of the sensory capacities of canine puppies reveals that they cannot consciously experience acute or chronic pain during at least the first week after birth, which is when they are usually docked. The contrary view is based on questionable between-species extrapolation of information about pain from neurologically mature newborns such as calves, lambs, piglets and human infants, which certainly can consciously experience pain in response to injury, to neurologically immature puppies which remain unconscious and therefore unable to experience pain until about two weeks after birth. Third, underpinned by the incorrect conclusion that puppies are conscious at the usual docking age, it is argued here that the well-validated human emotional drive or desire to care for and protect vulnerable young, leads observers to misread striking docking-induced behaviour as indicating that the puppies consciously experience significant acute pain and distress. Fourth, updated information reaffirms the conclusion that a significant proportion of dogs docked as puppies will subsequently experience persistent and significant chronic pain and heightened pain sensitivity. And fifth, other reported negative consequences of docking should also be considered because, although their prevalence is unclear, when they do occur they would have significant negative welfare impacts. It is argued that the present analysis strengthens the rationale for such bans or restrictions on docking of puppies by clarifying which of several justifications previously used are and are not scientifically supportable. In particular, it highlights the major roles the tail plays in canine communication, as well as the lifetime handicaps to communication caused by docking. Thus, it is concluded that non-therapeutic tail docking of puppies represents an unnecessary removal of a necessary appendage and should therefore be banned or restricted.
法律、法规及专业标准越来越倾向于禁止或限制对幼犬进行非治疗性断尾。这些限制措施通常基于以下理由:断尾会使狗失去尾巴在交流中的作用,断尾过程本身会造成剧痛,后续还会经历慢性疼痛和更高的疼痛敏感性,以及出现其他并发症。在此对这些方面进行重新审视。首先,对犬类交流中不可或缺的动态功能基础、感官成分和肢体语言关键特征进行科学严谨的研究表明,尾巴的作用被大大低估了。更具体地说,研究表明尾巴行为在犬类交流中根深蒂固,断尾会显著阻碍不同狗之间以及狗与人之间的明确互动。这些互动包括表达各种对犬类福利具有日常重要性的负面和正面情绪、情感及意图。此外,所有断尾犬在其一生中都可能经历这些阻碍,这对反对此类禁令或限制的人所声称的尾巴是可有可无的附属物这一观点提出了挑战。其次,与之形成对比的是,对幼犬感官能力的重新审视表明,它们在出生后的至少第一周内不会有意识地体验到急性或慢性疼痛,而这正是它们通常被断尾的时期。相反的观点是基于将关于疼痛的信息从神经学上成熟的新生动物(如小牛、羔羊、仔猪和人类婴儿,它们肯定能对损伤有意识地体验疼痛)不恰当地外推到神经学上未成熟的幼犬身上,幼犬在出生后约两周之前一直处于无意识状态,因此无法体验疼痛。第三,基于幼犬在通常断尾年龄时有意识这一错误结论,有人认为,人类出于关爱和保护脆弱幼崽的有效情感驱动力或愿望,导致观察者将断尾引起的明显行为错误地解读为幼犬有意识地体验到了严重的急性疼痛和痛苦。第四,最新信息再次证实了这样的结论:很大一部分在幼犬期被断尾的狗随后会经历持续且严重的慢性疼痛和更高的疼痛敏感性。第五,还应考虑其他报道的断尾负面后果,因为尽管其发生率尚不清楚,但一旦发生,它们将对福利产生重大负面影响。有人认为,当前的分析通过阐明先前使用的几种理由中哪些在科学上是可支持的、哪些不是可支持的,从而强化了对幼犬断尾实施此类禁令或限制的基本原理。特别是,它突出了尾巴在犬类交流中所起的主要作用,以及断尾对交流造成的终身障碍。因此,得出的结论是,对幼犬进行非治疗性断尾是对一个必要附属物的不必要切除,因此应该被禁止或限制。