Proceedings of the HSA Centenary International Symposium ‘Recent Advances in the Welfare of Livestock at Slaughter’ Historic Dockyard, Portsmouth, UK, 2011
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Foreword
- JK Kirkwood, C Mason, J Spence, H Barker
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- 01 January 2023, p. 1
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A review of the humaneness of puntilla as a slaughter method
- G Limon, J Guitian, NG Gregory
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- 01 January 2023, pp. 3-8
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Puntilla is a traditional slaughter method in which a knife is plunged into the back of the neck to sever the spinal cord. The aim is to produce immediate collapse of the animal. Puntilla is not condoned as a stunning method by the World Animal Health Organisation (OIE) because there is concern that the animal could be conscious during and after the neck stab. Nonetheless, it is still used in some developing countries. The effectiveness and humaneness of puntilla followed by neck sticking was examined at two slaughterhouses in Bolivia. Twenty llamas (Lama glama) and 309 cattle were observed during routine puntilla without stunning. The number of neck stabs was recorded, and then brain and spinal functions (rhythmic breathing, palpebral reflex and eyeball rotation) were assessed. In addition, the presence of specific cognitive responses (such as responses to a threat stimulus and noise, as well as to flavours and odours), were also assessed in cattle. Breed, sex, live weight, body condition score and the slaughterman's experience were recorded. Repeat stabbing was needed to penetrate the foramen ovale in 45% of the llamas and two of them attempted to stand following collapse after the initial stab. All llamas showed rhythmic breathing movements at the flank following puntilla and before sticking, and 95% had a positive palpebral reflex at the same time. Twenty-four percent of the cattle needed repeat stabbing. Repeat stabbing was significantly less frequent with experienced slaughtermen, and more frequent in heavyweight animals (> 380 kg). Brain and spinal responses were present in 91% of the cattle following the stabs. When cattle attempted to stand after a neck stab they were more likely to have rhythmic breathing, positive palpebral response and responsiveness to threat, noise and brief air stimulus applied to the face. These findings indicate that it is difficult in practice to penetrate the spinal cord with a single puntilla stab. Some nerve pathways are often functional after the neck stab and therefore it is highly likely that the animals remain conscious in at least some modalities for the next part of the slaughter procedure. The challenge in developing countries, however, is to find a strategy that encourages use of a method which limits suffering whilst being accessible for routine slaughter practice.
Advances in the electrical stunning and bleeding of ostriches
- LC Hoffman
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- 01 January 2023, pp. 9-13
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The stunning of ostriches (Struthio camelus) has traditionally been carried out with hand-held tongs whilst birds are held in a restraining area by applying pressure normally from behind by gently pushing on the tail feathers. The area is often a V-shaped structure, high enough that the stunning operator is not kicked. After stunning, the birds are rocked backwards and a rubberised leg clamp placed over the legs at the tarso-metatarsal bone allowing the birds to be chain-shackled by the big toes. This stunning procedure has been replaced by a new restraining and stunning mechanism which completely envelops the ostrich in a padded clamp holder. Double-padded sides restrain the bird's upper thighs and a rubberised foot clamp holds the feet so there is no physical damage to the bird. As the bird is electrically stunned with electrodes placed both sides of the head, the entire stunning box rotates 180° so that toe clamps can be applied without any danger to the stunning operators. Within 20 s of stunning, the birds are bled by means of a complete ventral cut to the neck and/or by thoracic sticking.
Human-animal relationships at sheep and cattle abattoirs
- GJ Coleman, M Rice, PH Hemsworth
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- 01 January 2023, pp. 15-21
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There are accumulating international data in a number of livestock industries that show that a negative attitude by stockpeople towards interacting with pigs, dairy cattle and poultry is correlated with increased levels of fear and stress in farm animals and in turn reduced animal productivity. While most of this research has been on-farm, one study has shown similar attitude-behaviour correlations in a pig abattoir. The major aim of this research was to examine the stockperson attitude-behaviour at sheep and cattle abattoirs. Twenty-two Australian abattoirs participated in the collection of stockperson attitudes and behaviour (81 stockpeople — 35 cattle stockpeople and 46 sheep stockpeople; six abattoirs slaughtering cattle, six slaughtering sheep and ten slaughtering both cattle and sheep). Several significant correlations between stockperson attitudes and behaviour were detected. In particular, the perceived pressures imposed by perceived lack of control over their actions, perceived time constraints, perceived effect of poor facilities and inappropriate beliefs about arousing livestock were all associated with frequent use of forceful handling behaviours by the stockperson. These results were similar to observations in pig abattoirs that have been reported previously. These relationships at cattle and sheep abattoirs indicate that there may be an opportunity to improve stockperson behaviour and consequently reduce stress in sheep and cattle at abattoirs by targeting attitudes (and behaviour) for improvement, with appropriate educational and training material in a way that is similar to the uses of such training with livestock species in farm settings.
Evidence for pain in decapod crustaceans
- RW Elwood
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- 01 January 2023, pp. 23-27
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Vast numbers of decapods are used in human food and currently subject to extreme treatments and there is concern that they might experience pain. If pain is indicated then a positive change in the care afforded to this group has the potential to produce a major advance in animal welfare. However, it is difficult to determine pain in animals. The vast majority of animal phyla have a nociceptive ability that enables them to detect potential or actual tissue damage and move away by a reflex response. In these cases there is no need to assume an unpleasant feeling that we call pain. However, various criteria have been proposed that might indicate pain rather than simple nociception. Here, with respect to decapod crustaceans, four such criteria are discussed: avoidance learning, physiological responses, protective motor reactions and motivational trade-offs. The evidence from various experiments indicates that all four criteria are fulfilled and the data are thus consistent with the idea of pain. The responses cannot be explained by nociception alone but, it is still difficult to state categorically that pain is experienced by decapods. However, the evidence is as strong for this group as it is for fish but the idea that fish experience pain has broader acceptance than does the idea of decapod pain. A taxonomic bias is evident in the evaluation of experimental data.
Auditing animal welfare and making practical improvements in beef-, pork- and sheep-slaughter plants
- T Grandin
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- 01 January 2023, pp. 29-34
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A welfare audit that utilises numerically scored, animal-based outcome measures has been used successfully by McDonald's and other restaurant companies for over ten years. In 2010, audit data from two restaurant companies indicated that all 30 of their North American plants rendered 95% or more of the cattle insensible with a single shot from a captive-bolt gun. Eight pork plants that used electrical stunning placed the tongs correctly on 99% or more of the pigs. All animals were insensible prior to hoisting. In 32 beef plants, the percentage of cattle vocalising in the stunning area was 5% or less. In 94% of the beef plants and 86% of the pork plants, none of the animals fell during handling. The worst falling score was 2% in two of the plants. High standards were attained by making simple changes. To improve welfare, plant managers did the following: improved stunner maintenance; installed non-slip floors in stun boxes and unloading ramps; and trained employees. To reduce balking and improve animal movement, the following modifications were made: illumination of dark race entrances; moving of lamps to eliminate reflections; reducing equipment noise; stopping employee yelling; installation of solid sides on races or shields to prevent animals from seeing activity outside the facility; and the elimination of air blowing in the faces of approaching animals. Employees were trained to use behavioural principles of animal handling such as the point of balance and the flight zone. The five numerically scored outcome measures in this audit are critical control points that can detect a variety of problems. They are: i) the percentage of animals stunned effectively with a single application of the stunner; ii) the percentage of animals falling during handling must be 1% or less to pass; iii) the percentage of pigs or cattle vocalising (moo, bellow, squeal) in the stun box or while entering into the stun box must be 5% or less to pass (vocalisation scoring is not used for sheep); iv) the percentage of animals moved with an electric goad; and v) the percentage of animals rendered insensible before hoisting must be 100% to pass an audit. An animal is scored as either silent or as a vocaliser and whether stunned correctly with a single application or not stunned correctly. The audit also contains a list of banned practices that will result in an automatic failure. To maintain improvements in handling, 23 plants have installed video cameras that are monitored by auditors viewing the footage over the internet. These external auditors perform numerical scoring at random times throughout the day. Video auditing over the internet is an important new tool for improving welfare.
Preliminary evaluation of the effectiveness of captive-bolt guns as a killing method without exsanguination for horned and unhorned sheep
- TJ Gibson, AL Ridler, CR Lamb, A Williams, S Giles, NG Gregory
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- 01 January 2023, pp. 35-42
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The current study aims to make welfare-based recommendations for gun/cartridge combinations and shooting positions that will ensure death of the sheep (horned, unhorned, rams and ewes), without the need for either sticking or pithing. The study examined the pathophysiology of captive-bolt gun (CBG) injuries that result in incomplete concussion leading to death. Behavioural, brainstem and cranial/spinal responses were examined along with gross pathology in 489 animals (116 polled ewes, 134 horned ewes, 117 polled rams and 122 horned rams) following a variety of CBG-cartridge combinations. Shooting horned rams was more challenging than unhorned sheep, partly because minor movements of the head at the time of shooting can result in deflection of the gun by the horns. Marksmanship was the definitive factor: 100% of animals that showed signs of incomplete concussion were found to have been shot incorrectly. The findings will have application when it is necessary to kill sheep on farms for disease control or euthanasia purposes.
Stress at slaughter in cattle: role of reactivity profile and environmental factors
- EMC Terlouw, C Bourguet, V Deiss
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- 01 January 2023, pp. 43-49
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During slaughter, cattle may be exposed to many potentially stress-inducing factors, of emotional and physical nature. A series of studies aimed to identify factors that may contribute to slaughter stress. During reactivity tests testing emotional stressors, Blond d’Aquitaine bulls were more reactive than Angus and Limousin bulls. However, no breed differences were found for stress indicators at slaughter. Indicators of post mortem (PM) muscle metabolism were correlated with stress reactions at slaughter, and with behavioural reactions and heart rates during the reactivity tests, including a sudden event and handling. Similarly, in Normand cull cows, stronger behavioural and physiological reactions during the slaughter procedure were associated with faster PM muscle metabolism. Reactions during the reactivity tests were also correlated with stress indicators at slaughter. A Principal Component Analysis indicated that the first and second axes were correlated with reactions to non-familiarity and to social isolation, respectively. Both axes were correlated with stress indicators at slaughter, suggesting that these two aspects contribute significantly to the emotional stress at slaughter. These experiments indicate that stress reactivity at slaughter may be predicted from behavioural and emotional stress reactions during reactivity tests. A third experiment found that compared with normally fed cows, 30-h food-deprived cows showed stronger startle and fear responses in response to a sudden event. Within a group subjected to a physical-effort treatment, compared to normally fed heifers, food-deprived heifers were more reactive to human exposure. This shows that the reactions to a given stressor may increase due to the presence of other stressors. Thus, in cattle, novelty, social disturbances and sudden events may contribute to slaughter stress and the simultaneous presence of several stressors during the slaughter period may exacerbate stress reactions.
Identifying reasons for stun failures in slaughterhouses for cattle and pigs: a field study
- M von Wenzlawowicz, K von Holleben, E Eser
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- 01 January 2023, pp. 51-60
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Checking the effectiveness of stunning was one of the major tasks when the authors evaluated the stunning process on request of the slaughterhouse managements, retailers or competent authorities in slaughterhouses in Austria, Germany and Switzerland between the years 2000 and 2011. A total of 50 assessments in slaughterhouses for cattle and 116 for pigs were included in this study. For every assessment the technical features of the stunning device, the performance by the personnel and the clinical signs of the animals after stunning were recorded. The assessments of captive-bolt (CB) stunning were made in 1,823 cattle. For pigs, 63 assessments were carried out in electrical stunning (26 in a pen [ESP], 24 in a trap [EST] and 13 in an automatic restrainer [ESR]) and 53 assessments in CO2 stunning, covering a total of 35,220 pigs (6,855 electrically stunned and 28,365 stunned using CO2). The proportions of assessments in which there were no failures were 28% (CB), 12% (ESP), 21% (EST), 31% (ESR) and 13% (CO). The mean percentages of animals showing signs not compatible with sufficient depth of stunning were 13.5 (± 19.0)% (CB), 12.5 (± 16.4)% (ESP), 10.9 (± 11.4)% (EST), 3.2 (± 3.3)% (ESR) and 7.5 (± 13.0)% (CO2) showing a high variability between premises assessed. Stunning effectiveness for cattle was better where a chest stick was performed compared to a neck cut. For pigs, less stunning failures occurred in electrical stunning where the two-cycle method (head/heart current) was applied compared to head-only stunning, and most of the failures in CO2 stunning were due to insufficient dwell time. Reasons for the stunning failures are described and recommendations given to improve the situation.
Veterinary certificates for emergency or casualty slaughter bovine animals in the Republic of Ireland: are the welfare needs of certified animals adequately protected?
- M Cullinane, E O’Sullivan, G Collins, DM Collins, SJ More
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- 01 January 2023, pp. 61-67
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All emergency and casualty bovines in the Republic of Ireland that are deemed to be fit for human consumption must be accompanied to the slaughterhouse by an official veterinary certificate (VC). Cullinane et al (2010) conducted a review of bovine cases consigned under veterinary certification to emergency (ES) and casualty (CS) slaughter in the Republic of Ireland during 2006 to 2008. The current paper further evaluates these results, with emphasis on the period of validity, transport distance and transport conditions, and considers whether the current VC adequately protects welfare. Of 1,255 veterinary certificates, the median time between certification and slaughter was 1 (minimum 0, maximum 452) day, with one-fifth in excess of three days. The median straight-line distance between farm and slaughterhouse was 22 km; 82 and 98% study animals were transported distances of no more than 40 and 100 km, respectively. In 27% of VCs, no slaughterhouse was designated; hence the transport distance was not limited. In 77% of all cases, the disability/injury was related to the locomotor system, including 35% with limb fractures. Veterinary certification of the latter as being fit for transport appears to have been in contravention of animal transport and welfare legislation. The welfare of animals would be improved if each VC included a certified period of validity. In future, veterinary certificates should state clearly a maximum period of validity between certification and slaughter, a maximum distance that the animal should be transported and a minimum level of comfort under which the animal must be transported. Historically, in the Republic of Ireland, there was no suitable non-transport alternative available to cattle producers wanting to salvage an otherwise healthy animal that had suffered an accident or injury resulting in acute pain. An alternative is now available, with the introduction of an on-farm emergency slaughter policy.
Improving the poultry shackle line
- JA Lines, P Berry, P Cook, CP Schofield, TG Knowles
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- 01 January 2023, pp. 69-74
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The most significant welfare problems associated with the current design of the shackle lines and water-bath stunners are the pain caused by compression of the birds’ legs in the shackles, the stress caused by being inverted and suspended by the legs, poor or inadequate stunning caused by the commercial need to minimise carcase damage, and poor water-bath entry. Research is described in which some practical solutions to these problems were investigated. The aim is to identify solutions that individually, or jointly, could be retro-fitted to existing plants, or incorporated into the design of new, small processing plants to improve poultry welfare. The development and commercial availability of such systems would enable small, local and niche market poultry processing lines to continue operating following the implementation of EC Council Regulation No 1099/2009.
Assessment of unconsciousness during slaughter without stunning in lambs
- P Rodríguez, A Velarde, A Dalmau, P Llonch
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- 01 January 2023, pp. 75-80
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The aim of this study was to assess brain activity in lambs during slaughter without stunning and its correlation with heart rate (HR) and the absence of physiological reflexes. The index of consciousness (IoC-view®) assesses consciousness by an algorithm that analyses the EEG and gives an index from 0 (unconscious) to 100 (conscious). Eight lambs (Merino breed) of 20 to 25 kg live weight were individually restrained in a stretcher and three skin electrodes were placed at the level of the frontal bone. The electrodes were connected to the IoC-view®. Two additional electrodes were placed on the chest and the HR was transferred to a watch monitor. Recording time started 2 min prior to sticking to attain the basal IoC and HR value of each animal. During bleeding, presence of corneal reflex and rhythmic breathing were recorded every 10 s until brain death. Rhythmic breathing disappeared at an average time of 44 (± 4.2) s after sticking, ranging between 30 and 60 s. The corneal reflex disappeared at 116 (± 11.01) s, ranging between 80 and 160 s after sticking. Changes in the brain activity occurred between 22 to 82 s after sticking (52 [± 20.2] s). In five out of six animals the HR increased (177 [± 22.7] beats min−1) compared to basal values (139 [± 8.4] beats min−1) at 115 (± 97.5) s after sticking. Both brain activity and physiological reflexes revealed that when bleeding is performed, through a transverse incision across the neck without stunning, the onset of unconsciousness could last 1 min which impaired animal welfare. This prolonged consciousness compared to other authors’ findings may be attributable to inefficient bleeding when lambs are slaughtered without head restraint.
Complications during shechita and halal slaughter without stunning in cattle
- NG Gregory, M von Wenzlawowicz, K von Holleben, HR Fielding, TJ Gibson, L Mirabito, R Kolesar
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- 01 January 2023, pp. 81-86
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This paper summarises the findings from five studies in eight countries on over 1,500 cattle slaughtered commercially by the halal or shechita methods without stunning. It reports the number of cuts applied to the neck, the cutting methods and the frequency of complications during the bleeding period. Complications during the bleeding period that occurred in some cattle included: (i) delay in the time to collapse, which was interpreted as late loss of consciousness; (ii) premature arrest of bleeding from the carotid arteries due to false aneurysm formation; and (iii) blood entering the respiratory tract during bleeding. These features are important as they determine or reflect the duration of consciousness following the cut and the potential for protracted suffering from wound nociception or blood irritating the respiratory tract. When cattle were not restrained following the halal cut, they took on average 20 s to collapse. Fourteen percent stood up again after an initial collapse, and 1.5% took more than 4 min before their final collapse. Eight percent took 60 s or longer to collapse, and those animals were more likely to have false aneurysms in the severed ends of the carotid arteries. False aneurysms, which were at least 3 cm in diameter, formed in the severed cardiac ends of the carotid arteries in 10% of cattle slaughtered by halal or shechita. Some false aneurysms formed in the severed ends of the carotid arteries within 7 s of the halal cut, and in 10% of the cattle bloodflow came to a halt in one of the arteries within 10 s. On average, the false aneurysms developed within 21 s. Nineteen percent of cattle slaughtered by shechita and 58% of cattle slaughtered by halal had blood lining the mucosa of the trachea. All animals had blood lining the glottis. In both situations there could be a sense of respiratory tract irritation from the blood. It is proposed that severing the carotids at the position in the neck which corresponds to C1 will reduce the frequency of false aneurysm formation and subsequent arrested bloodflow from the severed arteries, and it will deafferent the respiratory tract reducing the transmission of potentially unpleasant sensory signals associated with blood contaminating the upper and lower parts of the tract. Most cattle subjected to halal and shechita have the neck cut at a position which corresponds to C2 to C4, and changing to a cut at C1 could partly reduce the potential for suffering during slaughter without stunning.
Welfare during gathering and loading of deer bred for meat in Italy
- D Quiliquini, I Alpigiani
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- 01 January 2023, pp. 87-94
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The aim of this study was to evaluate welfare status and the implementation of Regulation (EC) 1/2005 during the gathering and loading of deer (Cervus elaphus) bred for meat in Northern Italy. Four journeys overland along with related operations of 45 deer, destined for game farms, were observed over a period of four months. Planning, animal-management procedures, equipment and facilities, such as enclosures and corridors, influenced the success of the operations and affected the safety of animals and operators. Environmental factors, such as land inclination, were also extremely influential. Elements of the gathering technique led to stress and hyperventilation in a number of animals that were rounded up. Chemical restraint of deer was complicated by consequent physical manipulation and an inability to control withdrawal periods in game reserves. Where facilities were specific to deer, animals displayed no signs of distress and loading was carried out in the absence of stressful behaviour. Instances in which means of transport were nonspecific for deer were characterised by falls, escape and trauma during loading and unloading. Where operators had been trained and had extensive knowledge of deer physiology and behaviour, welfare and the safety of professionals were promoted along with an overall regard for the relevant legislation. This study demonstrates a number of the challenges associated with deer transport and related activities. The paucity of specific legislation regarding the management and transport of farmed deer and the absence of European standard procedures have created a lack of harmonisation in transport procedures, ultimately jeopardising the welfare of deer.
WSPA and APSRI humane slaughter programme in China: STEPS®
- J Zili, R Kolesar
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- 01 January 2023, pp. 95-97
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The adoption of slaughter and pre-slaughter techniques to improve animal welfare and meat quality and safety is dependent on providing appropriate information, application and enforcement as well as information ownership by local people. The World Society for the Protection of Animals (WSPA) and Beijing Chaoyang Anhua Animal Product Safety Research Institute (APSRI) have been running a humane slaughter programme in China for more than three years. The aim of the programme is to improve the welfare of animals slaughtered in China through a three-pronged approach: i) train core-plant mid-level managers to be humane slaughter trainers; ii) provide guidance on legislation and codes of practice; and iii) develop and implement pre-slaughter and slaughter animal welfare curricula for undergraduate veterinarians. The production of in-country training material is based on a training-needs analysis conducted prior to the programme. Four Chinese trainers have completed the training and become national level trainers. In the last three years they have trained more than 5,000 staff from 800 slaughterhouses. Technical standards for slaughtering pigs, based on those of the OIE, have been adopted in China and the veterinary curriculum development is progressing. The programme has introduced many positive changes to the Chinese slaughter industry and the signs are positive for good progress.
Captive-bolt euthanasia of cattle: determination of optimal-shot placement and evaluation of the Cash Special Euthanizer Kit® for euthanasia of cattle
- JN Gilliam, JK Shearer, J Woods, J Hill, J Reynolds, JD Taylor, RJ Bahr, S Crochik, TA Snider
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- 01 January 2023, pp. 99-102
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Humane euthanasia of cattle represents a challenge to the beef and dairy industries. Penetrating captive bolt, while traditionally considered to be only a stunning method, can be an effective single-step euthanasia method if both the cerebral cortex and brainstem are disrupted. This report describes a preliminary study investigating the likelihood of brainstem disruption for two captive-bolt shot locations. Heads were collected from 15 cattle that died or were euthanised for reason unrelated to the study and were then randomly assigned to one of two shot placement groups. Heads in the first group (n = 7) were shot at the intersection of two lines drawn from the medial canthus to the opposite horn or top of the opposite ear. Heads in the second group (n = 8) were shot at the intersection of two lines drawn for the lateral canthus to the opposite horn or top of the opposite ear. The guns were held perpendicular (as assessed visually) to the plane of the forehead. Shot placement was then assessed using computed tomography and disruption of the brainstem was determined. In the first group, the captive bolt failed to disrupt the brainstem in any of the heads. In the second group, the bolt disrupted the brainstem in 6 of 8 heads. The results suggest that selecting a higher shot location leads more readily to disruption of the brainstem which reduces the risk of regaining sensibility and should therefore improve animal welfare when cattle are euthanised with a penetrating captive bolt.
Licensing poultry CO2 gas-stunning systems with regard to animal welfare: investigations under practical conditions
- K von Holleben, M von Wenzlawowicz, E Eser
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- 01 January 2023, pp. 103-111
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Carbon dioxide stunning of broilers is not permitted in Germany. However, the competent authority can license a system for testing, during which scientific evaluation with regard to animal welfare is required. Between 2004 and 2011 several aspects of three systems have been evaluated in Germany and Italy under practical conditions including: (i) supply to the stunning system; (ii) induction conditions; (iii) stunning effectiveness; and (iv) process control. The systems were: (i) LINCO progressive gas-stunning system in which broilers in their transport crates are lowered stepwise into a pit filled with CO2 and exposed to slowly increasing concentrations of CO2 in air up to between 50 and 65% with total dwell times between 275 and 440 s depending on birds’ weight; (ii) Stork PMT two-phase gas-stunning system (40% CO2/30% O2/30%N2 for 1 min/80% CO2 for 2 min) in which broilers are tipped onto a belt, on which they pass through the gas atmospheres; and (iii) Anglia Autoflow two-phase CO2-stunning system, in which the birds are exposed to the atmosphere in their crates. Results on the third system are pending as the investigation is still ongoing. In systems (i) and (ii) analysis of behaviour showed that birds were only exposed to high CO2 concentration (> 40%) after becoming unconscious. Stunning effectiveness was very high but, nevertheless, occasionally birds (0.027% LINCO system and 0.003% Stork PMT system) were able to regain consciousness. Examples of evaluation of behaviour during induction are presented in this paper and animal welfare aspects are compared. Controlled-atmosphere stunning systems for broilers using less than 40% CO2 until animals are unconscious, show obvious advantages compared to electrical water-bath stunning, for example, the avoidance of shackling and achieving high stunning effectiveness.
Pain perception at slaughter
- CB Johnson, TJ Gibson, KJ Stafford, DJ Mellor
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- 01 January 2023, pp. 113-122
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Recent developments related to quantitative analysis of the electroencephalogram (EEG) have allowed the experience of pain to be assessed more directly than has hitherto been possible. Variables derived from the EEG of animals anaesthetised using our minimal anaesthesia model respond to noxious stimulation in a manner similar to those from conscious animals. This methodology has been used in a variety of applications including the evaluation of analgesic options for painful husbandry procedures and investigation of developmental aspects of the perception of pain. We have now applied the minimal anaesthesia model to the question of the slaughter of calves by ventral-neck incision. A series of studies evaluated the magnitude of EEG response to the noxious stimulus of ventral-neck incision and the physiological mechanisms that underlie this response. We also investigated the EEG effects of stunning by non-penetrating captive bolt and the ability of such stunning to ameliorate the response to ventral-neck incision. The results demonstrate clearly, for the first time, that the act of slaughter by ventral-neck incision is associated with noxious stimulation that would be expected to be painful in the period between the incision and subsequent loss of consciousness. These data provide further support for the value of stunning in preventing pain and distress in animals subjected to this procedure. We discuss the development of the minimal anaesthesia model and its adaptation for use in the investigation of slaughter by ventral-neck incision as well as considering the contributions of these studies to the ongoing development of international policy concerning the slaughter of animals.
Aversion to the inhalation of nitrogen and carbon dioxide mixtures compared to high concentrations of carbon dioxide for stunning rabbits
- P Llonch, P Rodríguez, A Velarde, V Abreu de Lima, A Dalmau
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- 01 January 2023, pp. 123-129
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Stunning by inhalation of nitrogen (N2) and carbon dioxide (CO2) mixtures reduces aversion compared to high concentrations of CO2 in pigs and poultry. The objective of the study was to assess the aversion to 90% of CO2 (90C) and an alternative gas mixture of 80% N2 and 20% CO2 (80N20C) in commercial rabbits (Oryctolagus cuniculus). Sixty animals, divided into two groups, were used. During the first day, the rabbits of both groups were lowered in pairs into the pit with atmospheric air and their behaviour was recorded as control. During the second day, one group was exposed, again in pairs, to 90C and the other to 80N20C for 1 min. Exploratory behaviour and general activity were assessed 2 min before the exposure, during the exposure and for 2 min subsequently. During the exposure, signs of respiratory distress, loss of balance, muscle twitching and recovery of balance were also assessed. In the control sessions (atmospheric air), animals did not show respiratory distress or muscle twitching and were less active while the crate was descending than when gas treatments were applied. The percentage of animals with respiratory distress was higher in 90C (97%) than 80N20C (40%). Muscle twitching occurred earlier in 80N20C (97%; 23.9 s) than in 90C (17%; 37.4 s). A second phase of muscle twitching occurred only in 90C at 93.0 s. Mean latency of lost of balance and recovery were lower in 80N20C (24.2 and 98.6 s, respectively) than in 90C (28.2 and 110.2 s, respectively). It is concluded that rabbits showed less signs of respiratory distress to inhalation of 80N20C than 90C but more signs of aversion than when they were exposed to atmospheric air.
The effect of stun duration and level of applied current on stun and meat quality of electrically stunned lambs under commercial conditions
- C Berg, C Nordensten, J Hultgren, B Algers
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- 01 January 2023, pp. 131-138
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Electrical head-only stunning is a widely used method in sheep (Ovis aries) slaughter. To investigate the influence of current level on stun and meat quality in practice, two studies were carried out at a commercial slaughterhouse. In trial one, 200 lambs were randomly assigned to four groups with a current level of 0.6, 0.8, 1.0 and 1.25 A, respectively, using 50-Hz sine wave supply voltage and a stun duration of 10.5 s. In trial two, 135 lambs were randomly assigned to two groups, with electrical current of 1.25 A applied for 14 and 3 s. For each lamb, the position of the tongs was observed and classified as correct or incorrect. The stun quality was evaluated based on observations of the corneal reflex, eye movements, rhythmic breathing, head-righting reflex and kicking during the tonic phase. Blood splash (haemorrhages in Longissimus dorsi muscle) was evaluated four days after slaughter. Incorrect tongs’ positioning was seen commonly, and positively correlated with poor stun quality. The lowest current level tested produced an unsatisfactory stun in the majority of animals observed. Short stun duration increased the risk of a poor stun quality. There was no significant effect of current level, stun duration or tongs’ position on the risk of blood splash. These data underline the importance of a correct technique, including choice of tongs’ positioning, sufficient current levels and sufficient stun duration, for electrical stunning of lambs to achieve unconsciousness before sticking and thereby avoiding unnecessary suffering at commercial slaughter.