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Death and prolonged survival in nonstunned poultry: A case study
Accepted Manuscript Death & prolonged survival in non-stunned poultry: A case study John Cranley, MVB, MSc, MA, Dip. ECAWBM, MRCVS, OV PII:
S1558-7878(16)30150-2
DOI:
10.1016/j.jveb.2016.09.005
Reference:
JVEB 999
To appear in:
Journal of Veterinary Behavior
Received Date: 25 October 2015 Revised Date:
3 September 2016
Accepted Date: 6 September 2016
Please cite this article as: Cranley, J., Death & prolonged survival in non-stunned poultry: A case study, Journal of Veterinary Behavior (2016), doi: 10.1016/j.jveb.2016.09.005. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
ACCEPTED MANUSCRIPT Death & prolonged survival in non-stunned poultry: A case study John Cranley, MVB, MSc, MA, Dip. ECAWBM, MRCVS, OV
RI PT
Abstract EC Regulation 1099/2009, On the Protection of Animals at Killing Regulations (PATOK), requires the severance of “the two carotid arteries” to ensure each animal dies rapidly (Annex 3,3.2.). This requirement applies to stunned, non-stunned, manual and automated methods of killing.
SC
I observed the severance of carotid arteries in non-stunned, religious slaughter in a study of 250 nonstunned chickens. The birds were checked for aversive /anger type behaviors at 10 and 30 seconds and for the absence of corneal reflexes at 60 seconds post incision. Prolonged survivors were observed at 90,120,150 and 180 seconds post incision Spontaneous behaviors in non-stunned birds surviving over 90 seconds were recorded on a digital videocamera. At post mortem, neck wounds were inspected for severance of blood vessels and the findings were photographed.
TE D
M AN U
The studies were carried out by observing single birds, on a line running at less than 400 birds per hour, where meticulous technique was used. Of these non-stunned birds, 225 of 250 died at or before 60 seconds and 25 of 250 showed behaviors prolonged for more than 90 seconds post incision. These 25 birds had one or more intact carotid, as follows: 11 birds had two intact carotids, 2 birds had two carotids and 1 jugular intact, 5 birds had one carotid and 1 jugular intact, and 7 birds showed a single intact carotid. This failure to sever the brain’s blood supply may be linked to prolonged or resurgent, aversive or anger type behaviors. Aversive / anger type behavior was found in all checked birds from 10 seconds to over 40 seconds after the incision of both carotids and both jugulars, before death at 60 seconds. The prolonged fear/anger type behavior over 90 seconds, indicated a risk of consciousness and sensibility. I offered individual instruction on improved carotid severance techniques to religious slaughterers to avoid these risks to bird welfare. This welfare at slaughter study was compared to cattle and sheep work previously undertaken.
EP
Introduction As a veterinarian involved in neural scientific research interspersed with periods of supervision of welfare at slaughter over four decades, one develops an awareness of risks of consciousness in cattle, sheep, and birds while dying (Cranley 2011, 2012, 2014). Non-stunned calf slaughter captured my interest when I observed the disquieting survival for 300 seconds post cut in 3/100 animals. Anger in calves was not discernible, however fear or sensibility, particularly where prolonged survivors were standing, could not be discounted. Prolongation of life may have been due to false aneurysm formation (Gregory, 2011), which I had found from 40 seconds post carotid severance in calves. In sheep, corneal reflex duration was the measure used to assess the survival of signs of life. Corneal reflexes took up to 70 seconds to disappear (Cranley, 2012, 2014), however, the sheep’s carotids remained patent, bleeding freely. This clinical picture of corneal reflex activity was also reported in an experimental study of assessment of unconsciousness during slaughter without stunning in lambs using EEG electrodes to assess brain function and corneal reflexes. CNS reflexes were found to survive from 80-160 seconds post sticking, with brain wave activity lasting up to 82 seconds.(Rodriguez et al., 2012).
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The non-stunned broilers were conscious at incision, when both carotids must be severed. Initial behavior appeared to be tonic immobility from 0 to 10 seconds as described by Jones (1987), followed by aversive behavior from 10 seconds. By 30 seconds aggressive pecking behavior was found (unpublished data). Death occurred by 60 seconds post incision. However, there were a significant
ACCEPTED MANUSCRIPT
RI PT
number of birds which showed head, neck and mouth movement behavior for over 90 seconds. Death by exsanguination in calves, sheep, and birds requires that both carotids to be severed (EC Regulation 1099/2009 Annex 3.3, III.). Additionally, the severance of the jugular veins is essential for rapid death (Gregory and Wotton, 1986). The residual blood supply via the vertebral artery via the basilar to the circulus arteriosus and then to the base of the brain may be the final source of blood once carotid and jugulars are severed. Survival in poultry at slaughter was studied by Gregory (1984) and Gregory and Wotton (1986) who reported that a failure to sever both carotids may add two minutes to survival. In these studies, evoked activity was seen at 349 seconds post incision in some anaesthetized birds during slaughter.
M AN U
SC
Where the blood supply persists, brain function may continue. Resurgence of corneal reflexes in calves, sheep and birds was seen after electrical narcosis in association with hoisting of inverted animals (Cranley, 2014). Unlike corneal reflexes, behavior of either the aversive type or anger type requires limbic involvement, and as such, it signals potential risk to the welfare of animals during non-stunned slaughter. Anger/fear behavior was studied by Lorenz (1938) who used silhouettes of birds of prey, to elicit fear in vulnerable small birds. Recent studies located the mediator of aggression as vasoactive intestinal polypeptide (VIP) in the anterior hypothalamus of aggressive finches, which is associated with adrenal axis stimulation (Goodson et al., 2012). Materials and Methods My studies were un-funded, un-affiliated, anonymised, with consent from the management, who were actively interested in animal welfare. The UK Home Office confirmed that these studies were outside the remit of the scientific experimental Act (ASPA 2013 and 1986). The Royal College of Veterinary Surgeons was approached for ethical guidance in 2010, which they kindly supplied.
EP
TE D
The birds were commercial broilers from a Ross genetic source. They were supplied for slaughter from 37 to 40 days. The birds were fed a commercial ABN high performance diet. They were housed in a commercial open housed, non-caged system, and were caught by a specialist catching team. Birds were placed in plastic drawers, 15 per drawer, in a metal module (12 drawers per module). The modules were loaded and un-loaded by a welfare positive driver, who gave the birds the best welfare at loading, transport and un-loading, using a load one, skip one, load one system to allow for maximum ventilation before completing the gaps, and using the curtain best practice to a provide for optimal ventilation. Road journeys with 3,500 birds per load were 3 to 6 hours in duration and avoided all stops to provide continual ventilation. Unloading took place immediately upon arrival with visual welfare checks. Electric fans were applied to the correctly spaced modules to avoid heat stress, and on cold nights there was draught exclusion. Each drawer was removed from the metal modular frame onto a roller covered with a green fabric tent to reduce light and calm the birds.
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50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98
Each bird was removed by an operative from the plastic drawer and presented for non-stunned slaughter where he held the bird within a metal ring while the neck incision was made at 0 seconds. After the religious incision the operative placed the non-flapping bird head downwards into metal cones within 35 seconds. Observations were carried out in one slaughterhouse in the UK. The line speed did not exceed 400 birds per hour and the total kill each day was 3,500 birds. The study involved 250 non-stunned birds over two days. Data were recorded for 120 birds on day 1 and, one week later, for 130 birds on day 2. The birds were selected for assessment on a convenience basis spread throughout the day. All birds were slaughtered by a single incision using a razor with meticulous care.
ACCEPTED MANUSCRIPT
SC
RI PT
Birds were visually assessed at 10, 30, 60, 90, 120, 150, and 180 seconds after the religious incision. Each bird was followed from 0-180 seconds or until death. A digital stop-watch was used to measure the time from the incision to death, and from stunning to incision to unconsciousness. At 10 and 30 seconds post incision the birds were assessed for an avoidance/aversion reaction within the cone by introducing a finger into the bottom opening, while watching the tail feathers for signs of retrograde movement or the sensation of head avoidance movements. At 60 seconds, the absence of a corneal reflex, neck limpness, and absence of breathing or vent movement were evaluated to define death. All other observations were non-intrusive to avoid triggering an initial aversive or later anger type behavior while in restraint. The birds were removed from the cones after 60 seconds and shackled. However, a minority of the birds in shackles showed a persistent or resurgence of behavior which lasted longer than 90 seconds post incision. These behaviors were recorded using a digital videocamera. The prolonged survivors were identified before there was any risk of reaching the plucker while alive and removed from the line. As soon as possible after death, the neck wounds were examined and photographed for evidence of carotid and jugular severance. Results
M AN U
Of the 250 non-stunned birds studied, 25 (10%) were prolonged survivors (Figures 1 & 2), 11 with two intact carotids, 2 with both carotids (Figure 2) and 1 jugular intact, 5 with a single carotid and 1 intact jugular of the same side intact, and 7 birds had a single carotid intact.
TE D
The birds did not flap their wings from 0 to 5 seconds, between the incision and placement in cones. At 10 seconds all of the visible bird’s heads protruding through the narrow end of the cone were observed and 234 of 250 were checked for aversive type behavior within the cones. By 30 seconds the aversive type behavior had progressed to anger type pecking behavior in 234 of 250 birds. By 60 seconds all birds were dead in the cones except for the 25/250 prolonged survivors. These birds showed wing flapping, blinking, and mouth movements which may suggest fear/anger type behavior. The gaping mouth movements seen in some of the prolonged survivors may be a behavioral “calling” response (Figure 1), although the birds tried but could not vocalize after blood vessels, tracheas, their throats and vagus nerves had been severed.
EP
At 120 seconds 21/250 birds were prolonged survivors, at 150 seconds 14 remained as survivors, and 4 birds of 250 survived to 180 seconds. Discussion Gregory and Wotton (1986) referred to the cutting of one carotid plus one jugular as a slow method of killing vigorous birds,.Latex studies of the left and right internal carotid anastomosis, as well as the basilar artery in Gallus gallus by Aslan et al. (2006) illustrated the anatomy, which may explain the duration of prolonged survival by the maintenance of the brain’s blood supply via this anastomosis. When a single carotid remains intact, with the additional blood supply from the basilar artery, the vasculature resembles components of a partially severed circulus arteriosus as described originally by Willis (1668). The physiology of the brain’s blood supply in sheep and cattle from the carotids and the vertebral artery was explored by Baldwin and Bell (1963) who provided an explanation of what one subsequently encountered in studies on cattle and sheep (Cranley, 2011,2012).
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99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147
Carotid severance by meticulous slaughterers of chicken may fail. In this report there were 25 of 250 birds (10%) with an intact carotid and a high risk of sensibility. As part of my official duties, these types of observations are repeated each week. While this study took place at one slaughterhouse, official observations take place at three slaughterhouses. In the slaughterhouse discussed here it was much easier
ACCEPTED MANUSCRIPT
RI PT
to assess carotid severance after death on the selected/ marked birds, as the line was slowest, enabling accurate observation. The official approach has been to concentrate on retaining non-stunned bird in cones for 90 seconds, rather than assessing serial severance failures. Alternatively, one could use transparent or externally visible, internally darkened cones to avoid covering up unacceptable severance failures. High speed, non-stunned killing lines operate at over 7,000 birds per hour, thus obscuring any clear picture of conscious birds dying. Both “ normal” and prolonged survivors may remain hidden, with suffering exacerbated by high speed and poor severance technique. The evidence I have seen indicates that failure to sever poultry carotids may be a widespread welfare risk not only in non- stunned slaughter but in stunned slaughter also. This may be due, in part, to the location of the carotids at a depth of 2 mm within the musculature over the spinal column. While the jugulars are superficial, when they are severed, blood fills the wound, obscuring the muscles within which the carotids may remain hidden.
M AN U
SC
In automated slaughter of stunned poultry there is a danger that while the transverse cut is much deeper, severing the carotids, an intact jugular may be dragged across the wound where the revolving blade fails to make a transverse incision, or makes an angular incision leaving a carotids and a jugular intact. A side of the neck cut may also fail to sever a carotid or a jugular adjacent to an intact cranium in a stunned bird. Staff should always be on hand to kill these birds, but this plan is only possible where the line is running at less than 2,000 birds per hour.
TE D
The assessment of effective carotid severance is an essential component of animal welfare protection under EC Regulation 1099/2009, in stunned, non-stunned, automated or manual killing. Where slaughterers were presented with the evidence of intact carotids, the ensuing dialogue appears to have improved welfare, as the more professional slaughterers refined their technique to achieve compliance by severing both carotids.
References
EP
Conclusion Non-stunned, incised chicken in cones show aversive type behavior at 10 seconds post incision which proceeded to anger type behavior at 30 seconds. This behavioral pattern may be related to fight or flight type behavior, indicated by wing flapping and mouth movements in birds with severed necks blood vessels, tracheas and nerves, including the vagus. Death at 60 seconds was found where carotids and jugular were fully severed. However, prolonged survivors occurred, which was verified at post mortem, where evidence of failure to sever blood vessels in the necks of the birds was found.
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148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196
Aslan,K., Atalgin,H., Kurtal,I., Bozkurt, E.U., 2006. Patterns of the internal and cerebral carotid arteries in various avian species: a comparative study. Revue Med.Vet.157,12,621-624. Baldwin, B.A., Bell F.R., 1963. The blood flow in carotid and vertebral arteries in the sheep and calf. J. Physiol. 167, 448-452. Cranley, J., 2011. Sensibility during slaughter without stunning in cattle. Vet. Rec. doi. 10.1136/vr.d 1927 Google Scholar. Cranley, J., 2012. Slaughtering lambs without stunning. Vet. Rec. doi.:10.1136/v.r..e 1703 Google Scholar.
ACCEPTED MANUSCRIPT Cranley, J., 2014. Onset of death after non-stun slaughter. Vet. Rec. 175(14) ; 357. Cranley, J.J., 2015. Fear and Anger: Protection of animals at non-stunned slaughter afforded by EC Regulation 1099/2009. J.Anim. Welf. Law 47-52 August 2015.
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Cranley, J.J., 2013. EFSA MINUTES on the AHAW 78 plenary Session 22nd and 23rd October 2013 EFSA Parma. Invited Observers with Invited Questions to the AHAW. Gregory, N.G., 1984. A Practical Guide to Neck Cutting in Poultry. Meat Research Institute Memorandum No. 54. Agricultural and Food Research Council U.K.
Gregory, N.G. Wotton, S.B.,1986.Effect of slaughter on the spontaneous and evoked activity of the brain. Br. Poult. Sci. 27(2), 195-2005.
SC
Jones, R.B., 1987. Assessment of fear in adult laying hens: correlational analysis of methods and measures Br. Poult. Sci. 28(2), 319-326.
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Rodriguez,P., Velarde,A., Dalmau,A., Llanch,P., 2012. Assessment of unconsciousness during slaughter without stunning in lambs. Anim. Welfare, 21(2); 75-80.doi: 10.7120/096272812X13353700593644 ISSN 0962-7286
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Willis, T., 1668. Anima Brutorum, Library of St. Johns College Oxford access text by Permission of the President and Fellows.
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two
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249 250
Figure 1 A conscious bird at 2 minutes post incision in a non stunned bird.
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268 269 270 271 272
251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267
Figure 2 Three Non-Stunned Slaughtered Birds: The top bird with carotid arteries severed.
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Highlights For Review 1. Focus on Early Response to the Incision Aversion in cones. 2. Response later in cones showing anger type behavior. 3. Death at 60 seconds. 4. Prolonged Survival after miss cut 5. Assisting the slaughterers to improve their carotid severance.
S1558-7878(16)30150-2
DOI:
10.1016/j.jveb.2016.09.005
Reference:
JVEB 999
To appear in:
Journal of Veterinary Behavior
Received Date: 25 October 2015 Revised Date:
3 September 2016
Accepted Date: 6 September 2016
Please cite this article as: Cranley, J., Death & prolonged survival in non-stunned poultry: A case study, Journal of Veterinary Behavior (2016), doi: 10.1016/j.jveb.2016.09.005. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
ACCEPTED MANUSCRIPT Death & prolonged survival in non-stunned poultry: A case study John Cranley, MVB, MSc, MA, Dip. ECAWBM, MRCVS, OV
RI PT
Abstract EC Regulation 1099/2009, On the Protection of Animals at Killing Regulations (PATOK), requires the severance of “the two carotid arteries” to ensure each animal dies rapidly (Annex 3,3.2.). This requirement applies to stunned, non-stunned, manual and automated methods of killing.
SC
I observed the severance of carotid arteries in non-stunned, religious slaughter in a study of 250 nonstunned chickens. The birds were checked for aversive /anger type behaviors at 10 and 30 seconds and for the absence of corneal reflexes at 60 seconds post incision. Prolonged survivors were observed at 90,120,150 and 180 seconds post incision Spontaneous behaviors in non-stunned birds surviving over 90 seconds were recorded on a digital videocamera. At post mortem, neck wounds were inspected for severance of blood vessels and the findings were photographed.
TE D
M AN U
The studies were carried out by observing single birds, on a line running at less than 400 birds per hour, where meticulous technique was used. Of these non-stunned birds, 225 of 250 died at or before 60 seconds and 25 of 250 showed behaviors prolonged for more than 90 seconds post incision. These 25 birds had one or more intact carotid, as follows: 11 birds had two intact carotids, 2 birds had two carotids and 1 jugular intact, 5 birds had one carotid and 1 jugular intact, and 7 birds showed a single intact carotid. This failure to sever the brain’s blood supply may be linked to prolonged or resurgent, aversive or anger type behaviors. Aversive / anger type behavior was found in all checked birds from 10 seconds to over 40 seconds after the incision of both carotids and both jugulars, before death at 60 seconds. The prolonged fear/anger type behavior over 90 seconds, indicated a risk of consciousness and sensibility. I offered individual instruction on improved carotid severance techniques to religious slaughterers to avoid these risks to bird welfare. This welfare at slaughter study was compared to cattle and sheep work previously undertaken.
EP
Introduction As a veterinarian involved in neural scientific research interspersed with periods of supervision of welfare at slaughter over four decades, one develops an awareness of risks of consciousness in cattle, sheep, and birds while dying (Cranley 2011, 2012, 2014). Non-stunned calf slaughter captured my interest when I observed the disquieting survival for 300 seconds post cut in 3/100 animals. Anger in calves was not discernible, however fear or sensibility, particularly where prolonged survivors were standing, could not be discounted. Prolongation of life may have been due to false aneurysm formation (Gregory, 2011), which I had found from 40 seconds post carotid severance in calves. In sheep, corneal reflex duration was the measure used to assess the survival of signs of life. Corneal reflexes took up to 70 seconds to disappear (Cranley, 2012, 2014), however, the sheep’s carotids remained patent, bleeding freely. This clinical picture of corneal reflex activity was also reported in an experimental study of assessment of unconsciousness during slaughter without stunning in lambs using EEG electrodes to assess brain function and corneal reflexes. CNS reflexes were found to survive from 80-160 seconds post sticking, with brain wave activity lasting up to 82 seconds.(Rodriguez et al., 2012).
AC C
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49
The non-stunned broilers were conscious at incision, when both carotids must be severed. Initial behavior appeared to be tonic immobility from 0 to 10 seconds as described by Jones (1987), followed by aversive behavior from 10 seconds. By 30 seconds aggressive pecking behavior was found (unpublished data). Death occurred by 60 seconds post incision. However, there were a significant
ACCEPTED MANUSCRIPT
RI PT
number of birds which showed head, neck and mouth movement behavior for over 90 seconds. Death by exsanguination in calves, sheep, and birds requires that both carotids to be severed (EC Regulation 1099/2009 Annex 3.3, III.). Additionally, the severance of the jugular veins is essential for rapid death (Gregory and Wotton, 1986). The residual blood supply via the vertebral artery via the basilar to the circulus arteriosus and then to the base of the brain may be the final source of blood once carotid and jugulars are severed. Survival in poultry at slaughter was studied by Gregory (1984) and Gregory and Wotton (1986) who reported that a failure to sever both carotids may add two minutes to survival. In these studies, evoked activity was seen at 349 seconds post incision in some anaesthetized birds during slaughter.
M AN U
SC
Where the blood supply persists, brain function may continue. Resurgence of corneal reflexes in calves, sheep and birds was seen after electrical narcosis in association with hoisting of inverted animals (Cranley, 2014). Unlike corneal reflexes, behavior of either the aversive type or anger type requires limbic involvement, and as such, it signals potential risk to the welfare of animals during non-stunned slaughter. Anger/fear behavior was studied by Lorenz (1938) who used silhouettes of birds of prey, to elicit fear in vulnerable small birds. Recent studies located the mediator of aggression as vasoactive intestinal polypeptide (VIP) in the anterior hypothalamus of aggressive finches, which is associated with adrenal axis stimulation (Goodson et al., 2012). Materials and Methods My studies were un-funded, un-affiliated, anonymised, with consent from the management, who were actively interested in animal welfare. The UK Home Office confirmed that these studies were outside the remit of the scientific experimental Act (ASPA 2013 and 1986). The Royal College of Veterinary Surgeons was approached for ethical guidance in 2010, which they kindly supplied.
EP
TE D
The birds were commercial broilers from a Ross genetic source. They were supplied for slaughter from 37 to 40 days. The birds were fed a commercial ABN high performance diet. They were housed in a commercial open housed, non-caged system, and were caught by a specialist catching team. Birds were placed in plastic drawers, 15 per drawer, in a metal module (12 drawers per module). The modules were loaded and un-loaded by a welfare positive driver, who gave the birds the best welfare at loading, transport and un-loading, using a load one, skip one, load one system to allow for maximum ventilation before completing the gaps, and using the curtain best practice to a provide for optimal ventilation. Road journeys with 3,500 birds per load were 3 to 6 hours in duration and avoided all stops to provide continual ventilation. Unloading took place immediately upon arrival with visual welfare checks. Electric fans were applied to the correctly spaced modules to avoid heat stress, and on cold nights there was draught exclusion. Each drawer was removed from the metal modular frame onto a roller covered with a green fabric tent to reduce light and calm the birds.
AC C
50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98
Each bird was removed by an operative from the plastic drawer and presented for non-stunned slaughter where he held the bird within a metal ring while the neck incision was made at 0 seconds. After the religious incision the operative placed the non-flapping bird head downwards into metal cones within 35 seconds. Observations were carried out in one slaughterhouse in the UK. The line speed did not exceed 400 birds per hour and the total kill each day was 3,500 birds. The study involved 250 non-stunned birds over two days. Data were recorded for 120 birds on day 1 and, one week later, for 130 birds on day 2. The birds were selected for assessment on a convenience basis spread throughout the day. All birds were slaughtered by a single incision using a razor with meticulous care.
ACCEPTED MANUSCRIPT
SC
RI PT
Birds were visually assessed at 10, 30, 60, 90, 120, 150, and 180 seconds after the religious incision. Each bird was followed from 0-180 seconds or until death. A digital stop-watch was used to measure the time from the incision to death, and from stunning to incision to unconsciousness. At 10 and 30 seconds post incision the birds were assessed for an avoidance/aversion reaction within the cone by introducing a finger into the bottom opening, while watching the tail feathers for signs of retrograde movement or the sensation of head avoidance movements. At 60 seconds, the absence of a corneal reflex, neck limpness, and absence of breathing or vent movement were evaluated to define death. All other observations were non-intrusive to avoid triggering an initial aversive or later anger type behavior while in restraint. The birds were removed from the cones after 60 seconds and shackled. However, a minority of the birds in shackles showed a persistent or resurgence of behavior which lasted longer than 90 seconds post incision. These behaviors were recorded using a digital videocamera. The prolonged survivors were identified before there was any risk of reaching the plucker while alive and removed from the line. As soon as possible after death, the neck wounds were examined and photographed for evidence of carotid and jugular severance. Results
M AN U
Of the 250 non-stunned birds studied, 25 (10%) were prolonged survivors (Figures 1 & 2), 11 with two intact carotids, 2 with both carotids (Figure 2) and 1 jugular intact, 5 with a single carotid and 1 intact jugular of the same side intact, and 7 birds had a single carotid intact.
TE D
The birds did not flap their wings from 0 to 5 seconds, between the incision and placement in cones. At 10 seconds all of the visible bird’s heads protruding through the narrow end of the cone were observed and 234 of 250 were checked for aversive type behavior within the cones. By 30 seconds the aversive type behavior had progressed to anger type pecking behavior in 234 of 250 birds. By 60 seconds all birds were dead in the cones except for the 25/250 prolonged survivors. These birds showed wing flapping, blinking, and mouth movements which may suggest fear/anger type behavior. The gaping mouth movements seen in some of the prolonged survivors may be a behavioral “calling” response (Figure 1), although the birds tried but could not vocalize after blood vessels, tracheas, their throats and vagus nerves had been severed.
EP
At 120 seconds 21/250 birds were prolonged survivors, at 150 seconds 14 remained as survivors, and 4 birds of 250 survived to 180 seconds. Discussion Gregory and Wotton (1986) referred to the cutting of one carotid plus one jugular as a slow method of killing vigorous birds,.Latex studies of the left and right internal carotid anastomosis, as well as the basilar artery in Gallus gallus by Aslan et al. (2006) illustrated the anatomy, which may explain the duration of prolonged survival by the maintenance of the brain’s blood supply via this anastomosis. When a single carotid remains intact, with the additional blood supply from the basilar artery, the vasculature resembles components of a partially severed circulus arteriosus as described originally by Willis (1668). The physiology of the brain’s blood supply in sheep and cattle from the carotids and the vertebral artery was explored by Baldwin and Bell (1963) who provided an explanation of what one subsequently encountered in studies on cattle and sheep (Cranley, 2011,2012).
AC C
99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147
Carotid severance by meticulous slaughterers of chicken may fail. In this report there were 25 of 250 birds (10%) with an intact carotid and a high risk of sensibility. As part of my official duties, these types of observations are repeated each week. While this study took place at one slaughterhouse, official observations take place at three slaughterhouses. In the slaughterhouse discussed here it was much easier
ACCEPTED MANUSCRIPT
RI PT
to assess carotid severance after death on the selected/ marked birds, as the line was slowest, enabling accurate observation. The official approach has been to concentrate on retaining non-stunned bird in cones for 90 seconds, rather than assessing serial severance failures. Alternatively, one could use transparent or externally visible, internally darkened cones to avoid covering up unacceptable severance failures. High speed, non-stunned killing lines operate at over 7,000 birds per hour, thus obscuring any clear picture of conscious birds dying. Both “ normal” and prolonged survivors may remain hidden, with suffering exacerbated by high speed and poor severance technique. The evidence I have seen indicates that failure to sever poultry carotids may be a widespread welfare risk not only in non- stunned slaughter but in stunned slaughter also. This may be due, in part, to the location of the carotids at a depth of 2 mm within the musculature over the spinal column. While the jugulars are superficial, when they are severed, blood fills the wound, obscuring the muscles within which the carotids may remain hidden.
M AN U
SC
In automated slaughter of stunned poultry there is a danger that while the transverse cut is much deeper, severing the carotids, an intact jugular may be dragged across the wound where the revolving blade fails to make a transverse incision, or makes an angular incision leaving a carotids and a jugular intact. A side of the neck cut may also fail to sever a carotid or a jugular adjacent to an intact cranium in a stunned bird. Staff should always be on hand to kill these birds, but this plan is only possible where the line is running at less than 2,000 birds per hour.
TE D
The assessment of effective carotid severance is an essential component of animal welfare protection under EC Regulation 1099/2009, in stunned, non-stunned, automated or manual killing. Where slaughterers were presented with the evidence of intact carotids, the ensuing dialogue appears to have improved welfare, as the more professional slaughterers refined their technique to achieve compliance by severing both carotids.
References
EP
Conclusion Non-stunned, incised chicken in cones show aversive type behavior at 10 seconds post incision which proceeded to anger type behavior at 30 seconds. This behavioral pattern may be related to fight or flight type behavior, indicated by wing flapping and mouth movements in birds with severed necks blood vessels, tracheas and nerves, including the vagus. Death at 60 seconds was found where carotids and jugular were fully severed. However, prolonged survivors occurred, which was verified at post mortem, where evidence of failure to sever blood vessels in the necks of the birds was found.
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ACCEPTED MANUSCRIPT Cranley, J., 2014. Onset of death after non-stun slaughter. Vet. Rec. 175(14) ; 357. Cranley, J.J., 2015. Fear and Anger: Protection of animals at non-stunned slaughter afforded by EC Regulation 1099/2009. J.Anim. Welf. Law 47-52 August 2015.
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Rodriguez,P., Velarde,A., Dalmau,A., Llanch,P., 2012. Assessment of unconsciousness during slaughter without stunning in lambs. Anim. Welfare, 21(2); 75-80.doi: 10.7120/096272812X13353700593644 ISSN 0962-7286
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Willis, T., 1668. Anima Brutorum, Library of St. Johns College Oxford access text by Permission of the President and Fellows.
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Figure 1 A conscious bird at 2 minutes post incision in a non stunned bird.
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Figure 2 Three Non-Stunned Slaughtered Birds: The top bird with carotid arteries severed.
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Highlights For Review 1. Focus on Early Response to the Incision Aversion in cones. 2. Response later in cones showing anger type behavior. 3. Death at 60 seconds. 4. Prolonged Survival after miss cut 5. Assisting the slaughterers to improve their carotid severance.