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To summarize, requirements for restraining as well as possible welfare relevance of improper restraint depend on slaughter method and animal species. For all slaughter methods it is difficult to restrain animals of different sizes and shapes. This applies in particular to huge animals like adult cattle. The special challenge concerning slaughter without stunning is to manage the restraint during and after the cut. Concerns are summarized in chapter 4.
4
Slaughter methods (Principles and concerns)
4.1
Neck cutting without stunning
Slaughter without stunning is performed where religious rules do not allow stunning. According to the Dialrel glossary, religious slaughter means slaughter according to religious rules which does not necessarily mean that slaughter is carried out without stunning. Issues of restraint have been already mentioned in chapter 3. In the following the question of pain during the cut and time to loss of brain responsiveness after the cut will be discussed. 4.1.1
The cut
The question whether the cut is painful, even if it is performed by a perfectly trained operator with a perfectly sharp knife on a calm animal is most important with regard to animal welfare during slaughter without stunning. Pain in general, perception of pain and different qualities of pain have been described in chapter 2.1. During slaughter nociceptive pain produced by mechanical forces of cutting cannot be influenced by a clean cut. Meanwhile the severity of inflammatory pain, produced by tissue damage can be mitigated but not eliminated by a good throat cut (Brooks and Tracey, 2005; Woolf, 2004). Whilst wounds which involve tearing of tissue or multiple cuts will invoke greater nociceptor activation than clean cuts, nociceptors will still be activated even in response to a single neck cut or deep cut to sever the blood vessels of the neck, irrespective of the sharpness of the knife. Based on physiology it is known that large wounds usually elicit major pain responses (EFSA, 2004, page 21). Grandin and Regenstein (1994) described little or no reaction to the throat cut by calves and cattle, restrained in low-stress upright restraint system, except for a slight flinch where the blade first touched the throat. The animals made no attempt to pull away and there were almost no visible reactions of the animal’s body or legs during the throat cut. Little or no reaction to the cut occurred in 6 calves reported by Bager et al. (1992). Other scientists argue that pain will be substantially involved. They refer to a cut in order to achieve rapid bleeding will cause substantial tissue damage in areas well supplied with nociceptors (Kavaliers, 1989). Any cut intended to kill the animal by rapid bleeding will greatly activate the protective nociceptive system for perceiving tissue damage and cause the animal to experience a sensation of pain (EFSA, 2004, page 21). The tissues that are cut include skin, long hyoid bone muscle, trachea, oesophagus, both jugular veins, both common carotid arteries, both trunci vagosympathici, both nervi recurrentes, both trunci jugulars and parts of the long throat muscle (KÜnig, 1999). Lamboij and Kijlstra (2008) in their review support the above mentioned view that the neck cut itself will cause the sensation of pain since this area of incision has a high density of pain receptors. In some animals however a temporary acute shock may block the sensation or expression of pain (Lambooij and Kijlstra, 2009). Reports on behavioural reactions of animals during slaughter without stunning are often based on anecdotal observations. Where the conditions of the cut are not clearly depicted (e.g. sharpness of the knife, skills of the operator), or where it is not mentioned whether the reactions to the first cut or to a multiple cut or back up cut are described. An additional