A scientific comment on the welfare of domesticated ruminants slaughtered without stunning

Abstract

This review provides a scientific comment on the welfare of ruminants slaughtered by ventral-neck incision without stunning. Evidence is derived from studies of calves, sheep and goats. Reference is also made to findings in other mammals including humans. Pain is an inherently subjective experience and only indirect indices are available in animals. Neurophysiological tools are widely used in humans to assess pain and have demonstrated that electroencephalographic (EEG) variables correlate well with subjective evaluations of pain. These neurophysiological tools have also been applied in animal studies. In humans pain is associated with major cutting injuries and it is widely accepted that farm animals also experience pain due to such injuries. Overwhelming international scientific opinion has long been that slaughter by neck incision of conscious animals causes pain. A series of studies in calves demonstrated that slaughter by ventral-neck incision is likely to be perceived as painful. It is proposed that, as in cattle, non-stunned sheep and goats would experience pain in a similar manner. The precise assessment of the point after slaughter at which non-stunned animals become insensible remains a major methodological challenge. In sheep it is at least 2-8 seconds, but may be 8-20 seconds in duration. In cattle the mean duration is similar, but can commonly be extended to longer than 60 seconds with occasional instances of even greater durations. Taken together, these findings indicate that because the slaughter of cattle, sheep and goats by ventral-neck incision without prior stunning is likely to cause pain, this poses a risk to animal welfare.

Feature series: animal welfare: current issues and recent developments

“…As science progresses, what may have been accepted as fact becomes blurred as shown by the admission in the review by Johnson et al (2015) that "the precise assessment of the point after slaughter at which non-stunned animals become insensible remains a major methodological challenge. "…”

“…There is an interesting introduction to the welfare implications of breathlessness (Beausoleil and Mellor 2015b) and a review of various husbandry procedures carried out on piglets (Sutherland 2015). The slaughter of livestock without stunning, a subject familiar to readers of this Journal, is reviewed by Johnson et al (2015). The authors of the papers are based in New Zealand or Australia, and illustrate the quality of the research in animal welfare science being undertaken here (Stafford 2013).…”

Assessing unconsciousness in livestock at slaughter

“…Gibson et al, 2007;Gibson et al, 2009a;Mellor et al, 2009) state that the ventral neck cut is a noxious stimulus and that there is strong evidence that this cut would be perceived as painful from the time of the neck cut until loss of consciousness. The general opinion is that slaughter by neck incision of conscious animals causes pain and that bleeding while conscious may distress the animal (Gregory, 2005a;Johnson et al, 2015). Taken together, consciousness in sheep slaughtered without prior stunning is lost 2 to 20 s after the neck cut, with little variation between animals.…”

“…sensible and/or aware, animals causes them pain and distress. The general opinion is that slaughter by neck incision of conscious animals causes pain and that bleeding while conscious may distress the animal (Gregory, 2005a;Johnson et al, 2012;Johnson et al, 2015). Taken together, loss of consciousness is instant following mechanical-and electrical stunning.…”

“…Bleeding follows when an animal's throat is cut, using a very sharp knife, severing the major blood vessels in the animal's neck that supply the brain, ensuring rapid blood loss and eventually resulting in death of the animal (EFSA, 2004). It is generally acknowledged that slaughter by neck incision of conscious animals causes pain and that bleeding while conscious may distress the animal (Gregory, 2005a;Johnson et al, 2012;Johnson et al, 2015). European legislation therefore states that animals should be stunned before bleeding, with exception of animals subject to particular methods of slaughter prescribed by religious rites (Council Regulation (EC) 1099/2009).…”