Killing of cattle via electrical stunning

For disease control in the case of epidemics killing of cattle via electrical stunning is a method of choice. The official veterinarian is responsible for monitoring the adhesion to animal welfare principles during electrical stunning and killing.This requires specialised knowledge and experience as the symptoms of effective stunning are quite variable in cattle. Signs of effective and ineffective stunning are described below. In addition to suitable technical equipment, restraint of the animals and correct use of the equipment, neurophysiological processes have to be considered. Calm handling of the animals avoiding stress is a prerequisite for ensuring animal welfare and minimising pain especially when killing cattle using electrical methods.     

A study of preslaughter pig handling and stunning in selected South African Highveld Region abattoirs

The study hypothesis was that pre-slaughter handling is not conducted in such a way that pigs can be considered humanely slaughtered, nor is it conducive to promoting those properties of fresh meat that could enhance pork quality. The 1st phase of the investigation was aimed at confirming the present compliance level within the prescribed norms. To this end the importance of stunning induction requirements for effective electrical stunning, the welfare implications relating to the pre-slaughter handling of pigs and the stunning and sticking techniques were investigated. Pre-slaughter welfare of the pigs at the abattoir was found to be influenced at the outset by the origin and type of pig slaughtered, the daily throughput range of pigs and the type of abattoir involved. A disappointing pre-arrival aspect was that deficiencies in road motor vehicles were observed while off-loading pigs. Through poor design or lack of maintenance, another factor that hampered free movement of pigs was the off-loading facilities. The nature of animal behaviour in the pens, in the passages and when going into the stunning area was directly related to the pig handling efficiency and to the nature and extent of design and maintenance problems with equipment. None of the abattoirs had a well designed in-feed to a well planned stunning area/facility, and a very high level of pig pre-slaughter stress prevailed. The optimum position of the electrodes is virtually impossible to attain under practical conditions and the practice of repeat application of electrical stunning is common. Of the total sample size (n = 1175), 34% were difficult to shackle, 90% of these being from the abattoirs tending to slaughter more routinely a wide range of different sized pigs. In this survey 149 pigs (13%) required more than a single sticking attempt to bleed out properly, considerably higher than in other published reports.     

The least requirements for the rotation of swine for slaughter from loading to transport to resting time until stunning from the viewpoint of animal protection and meat quality

1. According to the loading density there is a significant increase of the physical burden (strain) during a transport of pigs to the slaughterhouse. Keeping up minimal requirements (kgs pigs/sqm) the stress reaction decreases and the meat quality becomes better. 2. Each transport produces excitement which can be shown in higher respiratory and heart frequencies. The slaughtering of excited animals shows a higher percentage of carcasses with bad meat quality. Waiting times from at least 2 hours up to a maximum of 4 hours shows that the percentage of carcasses with a better meat quality increases. 3. Handling of animals at the slaughterhouse prior to stunning by dividing the number of pigs into small groups of at least 9 animals is very important especially because it reduces the excitement of the pigs prior to stunning. The stunning results are getting better. Mistakes in handling pigs prior to stunning especially in guiding them to the stunning place usually destroy all positive efforts for optimal transparent conditions and keeping up waiting times after transport. 4. The last step ahead to the stunning equipment. No good solution does exist which makes the pigs willingly do this last step and enter the place where the stunning is performed. This results in the CO2 stunning system itself as well as in the automatic electrical stunning equipment using a restrainer. 5. Stunning with CO2.     

Animal welfare aspects of the killing of fish

According to the Animal Protection Law (1986) fish are to be killed by methods which do not cause pain. However, the regulations do not cover the killing of non-food fish. A questionnaire, conducted among 85 fish scientists, revealed that single fish should be killed by a blow on the head, and larger numbers by electrical methods or by use of chemicals. Decapitation was proposed for eels. A regulation from 1936 stipulates the methods for the slaughtering of food fish. Mechanical or electrical stunning is compulsory except for eel and flatfish. The questionnaire showed that in general the present legal regulations are sufficient for the slaughtering of fish with the exception of eels. The commercially available apparatus for stunning and killing do not always fulfill the requirements of animal protection, slaughtering technology and safety for the user. Official testing of these apparatus as well as the evaluation of new methods--like CO2-stunning--are necessary in order to prevent the use of methods which are feasible, but do not fulfill animal welfare, especially for eel.     

Variation in the mortality rate of turkeys during transport to the slaughterhouse with travel distance and month

Failure to comply with animal welfare requirements during the transport of turkeys to the slaughterhouse increases stress in animals, which is manifested by increased mortality rate during transport. The numbers of turkeys that died during transport or soon after arrival may serve as an important parameter to indicate the level of animal welfare during transport of turkeys. The number of turkeys that died during transport to slaughterhouses in the Czech Republic in the period from 1997 to 2004 was investigated. The mortality rate found was 0.28% +/- 0.06% but varied with travel distance. The lowest mortality rate was found in case of travel distance below 50 km (0.18% +/- 0.08%) while long travel distances resulted in considerable increase in the mortality rates of turkeys (between 0.28% +/- 0.07 and 0.37% +/- 0.10%). The mortality rate of transported turkeys was also affected by the particular month of the year. Thus, the highest overall mortality rate occurred at long travel distances during winter months, i.e. in December (0.34% +/- 0.18%), January (0.32% +/- 0.06%), and February (0.36% +/- 0.07%). The comparison of individual years has shown a long-term trend towards a decrease in turkeys' mortality during transportation to slaughterhouses from 0.32% in 1998 to 0.20% in 2004. The decrease was statistically significant (Spearman's rank correlation coefficient r = -0.86, p < 0.01). This trend can be evaluated as positive.     

Animal welfare and workers' protection during electric stunning of poultry for slaughter

Every slaughter process involves problems as to animal welfare as well as safety aspects and the protection of workers. With poultry these are basically concentrated on electrical stunning. Electrical currents and voltages suitable for stunning slaughter animals are principally also hazardous for man in what respect body resistance is of crucial importance. Potential hazards have to be looked upon as present in spite of existing safety regulations. Comparatively high stunning voltages for poultry recently proposed because of animal welfare considerations have met objections not only from the viewpoint of meat hygienic but workers' safety regulations as well. While the former meanwhile could be overcome the latter still has to be investigated, especially as a regulation on the electrical stunning of poultry is currently being prepared. In this respect the question whether adequate stunning efficiency can be obtained by reducing the voltage and prolonging the time of exposure is of special interest. First preliminary results of such investigations are presented. To ensure workers' safety other related aspects should also be taken into account and examined for improvements.     

CO2-stunning of slaughter pigs: effects on EEG, catecholamines and clinical reflexes

Investigations were carried out on the response of slaughter pigs to CO2 stunning with two different gas concentrations (80 vol%, 90 vol%, 73 s) under practical conditions in a one gondola-dip-lift system. EEG measurements were performed and blood constituents such as catecholamines (adrenaline, nor-adrenaline) and lactate as well as clinical reactions (nasal septum and corneal reflex, heart beats) investigated. Special EEG-electrodes were adapted for the measurement on pigs and a mobile data logger was prepared for the use in the lairage of the slaughter house and in the stunning unit. The CO2 concentrations were measured continuously close to the head of the pigs when transported up and down in the stunning gondola. The results show that the technique is suited to monitor the effects of different CO2 gas concentrations on the EEG of the pigs under practical conditions. There is strong evidence that CO2 concentrations of 80 vol% applied over 70 s as required by law are not sufficient to stun pigs properly. A large part of the animals still showed typical reflexes when leaving the stunning pit. When an atmosphere of 90 vol% CO2 is applied, most animals are already dead before bleeding commences. This may create problems in respect to meat hygiene. The blood analysis revealed very high concentrations of catecholamines after stunning. The values for adrenaline and nor-adrenaline in the sticking blood rose by a factor of about 1000 as compared to the concentrations in blood samples taken in the lairage before stunning. It seems necessary to revise the current legislation on gas stunning and to look in greater detail in the effects of CO2 stunning on the welfare of slaughter pigs.     

Field report from large-scale killing of ducks

An outbreak of avian influenza in August 2007 resulted in the culling of hundreds of thousands of Peking ducks. An earlier tutorial had shown that whole house gassing with carbon dioxide to kill waterfowl has to be refused because of interference with animal welfare. Culling by electrocution is a reliable method that fulfils animal welfare requirements. Stationary electrocution lines for slaughtering should be preferred if suitable for the killing of the birds. Mobile electrocution lines (MET) are a good alternative or supplementation with a capacity of circa 2,500 animals per hour. MET are suitable for killing Peking ducks with a weight of approximately 500 g. At least two veterinarians are required per MET for the supervision of animal welfare during culling. When following German animal welfare laws, killing in mobile gas containers filled with carbon dioxide is an alternative with a capacity comparable to that of MET. The problem of looking into the containers for controlled stunning and killing can be solved by installing observation windows. Manpower requirements are comparable to those of MET, while requirements for material and transportation are unlikely higher. This method is suitable for birds which are too small to be killed by electrocution.     

Animal welfare and disease control regulations for killing cattle, swine and sheep with the help of a transportable electric stunning facility (SCHERMER, type EC)

Stamping-out of animals in case of infections diseases has to meet the requirements resulting from animal welfare, disease prevention, and practicability under conditions in practice. This is well qualified by application of electrical shock stunning with subsequent generation of ventricular fibrillation in cattle, swine and sheep. The scientific elements of the method, the procedure, and experiences in application of the method during the stamping-out of 340 cattle, 980 swine, 152 sheep and 18 goats are discussed in the paper.     

Reflexes and loss of sensibility following head-to-back electrical stunning in sheep

The effects of head-to-back electrical stunning on the incidence of post-stunning reflex activity and cortical evoked responses were investigated in sheep. The stuns were effective in terms of inducing epileptiform activity and they resulted in cardiac fibrillation which ensured that there was no recovery of consciousness. Even though the corneal reflex and respiratory gasps were present, in 10 out of 12 sheep there were no concomitant visual and somatosensory evoked responses following a stun. In the remaining two, the responses were rudimentary and it would be unwise to conclude that the animals were conscious. It is suggested that brain stem reflexes following this stunning method should not be relied on as indices of recovery. The results support the view that an electrical stunning method which induces cardiac fibrillation results in improved animal welfare.     

Evaluation of stunning/killing methods for quail (Coturnix japonica): bird welfare and carcase quality.

1. The welfare and carcase quality implications of stunning/killing 7-week-old Japanese quail with either an electric current, 90% argon in air or a mixture of 30% carbon dioxide and 60% argon in air were investigated in 3 separate experiments. 2. The results showed that exposure of quail to either argon or the carbon dioxide-argon mixture resulted in loss of posture on average at 9 and 8 s respectively. In both gas mixtures, convulsions started 6 s after the loss of posture and the duration of clonic phase (wing flapping) did not differ significantly between the 2 gas mixtures. However, the duration of the tonic phase was found to be slightly longer with the carbon dioxide argon mixture than with argon alone (P<0.05). 3. The absence of a positive response to toe pinching performed soon after the loss of posture indicated that the birds became unconscious and insensible to pain before the onset of convulsions. 4. Carcase dissection showed that, in comparison with the electrical stunning, gas stunning/killing of quail in transport containers eliminated the problem of broken bones and significantly reduced haemorrhaging in breast and leg muscles.     

Controlled atmosphere stunning of broiler chickens. II. Effects on behaviour, physiology and meat quality in a commercial processing plant

1. The effects of controlled atmosphere stunning on behavioural and physiological responses, and carcase and meat quality of broiler chickens were studied experimentally in a full scale processing plant. 2. The gas mixtures tested were a single phase hypercapnic anoxic mixture of 60% Ar and 30% CO(2) in air with <2% O(2), and a biphasic hypercapnic hyperoxygenation mixture, comprising an anaesthetic phase, 40% CO(2), 30% O(2), 30% N(2), followed by an euthanasia phase, 80% CO(2), 5% O(2), 15% N(2). 3. Birds stunned with Ar + CO(2) were more often observed to flap their wings earlier, jump, paddle their legs, twitch and lie dorsally (rather than ventrally) than those stunned with CO(2) + O(2). These behaviours indicate a more agitated response with more severe convulsions during hypercapnic anoxia, thereby introducing greater potential for injury. 4. Heart rate during the first 100 s of gas stunning was similar for both gases, after which it remained constant at approximately 230 beats/min for CO(2) + O(2) birds whereas it declined gently for Ar + CO(2) birds. 5. In terms of carcase and meat quality, there appeared to be clear advantages to the processor in using CO(2) + O(2) rather than Ar + CO(2) to stun broiler chickens, for example, a much smaller number of fractured wings (1.6 vs. 6.8%) with fewer haemorrhages of the fillet. 6. This study supports the conclusions of both laboratory and pilot scale experiments that controlled atmosphere stunning of broiler chickens based upon a biphasic hypercapnic hyperoxygenation approach has advantages, in terms of welfare and carcase and meat quality, over a single phase hypercapnic anoxic approach employing 60% Ar and 30% CO(2) in air with <2% O(2).     

Religious slaughter in Italy

This research aims to understand the prevalence of religious slaughter practices in Italy. Two different ways of slaughtering animals are identified. Conventional slaughter is performed with prior stunning; kosher slaughter is practiced without stunning. Halal slaughter is performed for most animals without stunning. Halal slaughter with prior stunning is acceptable for 5.90% of small ruminants. For Halal slaughter in Italy, the terms “religious slaughter with stunning” and “religious slaughter without stunning” should be used to differentiate religious slaughter practices, keeping animal welfare in perspective.

     

Ritual slaughter: animal friendly slaughter and protection of animals in Islam

A report is given on history and procedures of ritual slaughter from the point of view of a Moslem representative. The term sacrifice and the religious meaning of the offering feast are explained on the basis of the Abrahamian tradition. The social aspect of ritual slaughter is that two thirds of the slaughtered animal are given to the poor or served as meal to guests and relatives. One third is saved for the own family only. The Islamic religion acknowledges the responsibility of man for animals as creatures of god whose life and well-being have to be protected, nobody is allowed to subject animals to pain, suffering and damage without a sound reason. The ritual slaughter aims at complete debleeding. Blood is symbol life and soul and the breath of life. It must leave the body completely before consumption because it is not allowed to eat animals alive. Electric stunning is allowed if the animal is unconscious and not dead. The consumption of dead animals is forbidden by religion. It is recommended to introduce more veterinarian expert knowledge in the discussion.     

The electric stunning of pigs for slaughter

Electrical stunning is the most common stunning method in the FRG. Beside manual stunning with tongs (70-250 V) there are also automatic high-voltage stunning devices (400-1000 V) in use. In the FRG the maximally allowed stunning voltage is 250 V for manual working apparatus. Electrical stunning is acceptable from the animal point of view, if a minimal current of 1.2 ampere is reached, immediately after the beginning of the stunning operation. This current provokes an epileptic insult combined with unconsciousness. Immobilisation combined with stiffness can be reached with lower currents. The current, flowing during stunning operation, depends on both stunning voltage and resistance between electrodes and surface of the animal. Current curves were recorded during manual stunning operations with different kinds of tong and different voltages. It was found, that a stunning voltage lower than 250 V under practise conditions is not acceptable from the animal point of view, because 1.2 ampere were not reached within 1 second. Electrical stunning with 250 V is acceptable, when an exact positioning of the tongs is possible because of a short fixation of the pig. The following demands can be formulated for an effective electrical stunning of pigs: 1. pigs should be wet prior to stunning. 2. positioning of the tongs must be done in such a way that the brain lies on the shortest line between the two electrodes. 3. between electrodes and pig surface should be an intensive contact. 4. stunning voltage should be at least 250 V, better higher. 5. bleeding should be done not later than 20 seconds after the end of the stunning, the time between bleeding and scalding being at least 3 minutes.     

Effectiveness of different electrical stunning regimens for turkeys and consequences for carcase quality

This study examined the effectiveness of electrical stunning of turkeys applied at 150 mA per bird utilising a range of waveform-frequency combinations. In addition, the effect of stunning treatment on subsequent carcase quality was examined. The effectiveness of stunning, as judged by time to recovery, was similar regardless of bird weight or applied stunning treatment. Increasing waveform frequency was associated with a decrease in the prevalence of ventricular fibrillation, although turkeys appeared more susceptible than broilers. Use of the higher frequency waveforms (500 and 1500 Hz) was associated with a marked improvement in carcase quality, particularly with regard to breast muscle haemorrhaging and their use may result in considerable commercial advantage.     

Controlled atmosphere stunning of broiler chickens. I. Effects on behaviour, physiology and meat quality in a pilot scale system at a processing plant

1. The effects of controlled atmosphere stunning on the behaviour, physiology and carcase and meat quality of broiler chickens were studied experimentally in a pilot scale plant. 2. Gas mixtures tested were: single phase anoxic mixture (90% Ar in air, <2% O(2)); single phase hypercapnic anoxic mixture (60% Ar, 30% CO(2) in air, <2% O(2)); and biphasic hypercapnic hyperoxygenation mixture (anaesthetic phase, 40% CO(2), 30% O(2), 30% N(2); euthanasia phase, 80% CO(2), 5% O(2), 15% N(2)). 3. Anoxic stunning resulted in the least respiratory disruption, mandibulation and motionlessness, but most head shaking, leg paddling and twitching. Loss of posture occurred soonest with hypercapnic anoxia with the earliest and most twitching and wing flapping in individuals and earliest leg paddling. Biphasic birds were most alert, exhibited most respiratory disruption and mandibulation, and had the latest loss of posture and fewest, but longest bouts of wing flapping and least leg paddling and twitching. 4. Significant and sudden bradycardia and arrhythmia were evident with all gas mixtures and were not related solely to anoxia or hypercapnia. Birds stunned by Ar anoxia showed a slightly more gradual decline from baseline rates, compared with hypercapnic mixtures. 5. Few differences were found between gas mixes in terms of carcase and meat quality. Initial bleeding rate was slowest in biphasic-stunned birds, but total blood loss was not affected. Acceleration of post-mortem metabolism in anoxic-stunned birds was not sufficient to allow de-boning within 5 h without the risk of tough meat. 6. On welfare grounds and taking into account other laboratory and field studies, a biphasic method (using consecutive phases of anaesthesia and euthanasia) of controlled atmosphere stunning of broilers is potentially more humane than anoxic or hypercapnic anoxic methods using argon or nitrogen.     

Assessment of cattle welfare at a commercial slaughter plant in the northwest of Mexico

Slaughter plants have been undergoing radical transformations in recent years due to the need to increase efficiency and incorporate new technologies for the improvement of the infrastructure, animal welfare, and product quality. The aim of this study was to assess the cattle welfare status during the unloading, lairage, stunning, bleeding and quantify bruising incidence at a commercial slaughter plant in the northwest of Mexico. We monitored 8,118 cattle during the unloading, lairage, stunning, bleeding, and carcass bruise incidence. Our results showed that in the unloading stage, 2% of the cattle vocalized, 5% were prodded with an electric goad, and 4% either slipped or fell. In the lairage stage, 12% of the animals vocalized, 80% prodded with an electric goad, and 8% of the animals slipped or fell. In the stunning stage, 10% of the animals vocalized, 67% prodded with an electric goad, and 15% of the animals slipped or fell. Ninety-five percent of the animals were stunned with a single shot, and 51% of the animals were effectively desensitized. Ninety-two percent of the carcasses had some type of bruise. Although the slaughter plant had adequate infrastructure and stringent operational standards, in all of the stages except unloading handling had an impact on the welfare of the animals being slaughtered.     

Evaluation of a gas stunning equipment used for turkeys under slaughterhouse conditions

Physiological responses (eyelid closure and interphalangeal reflex) and meat quality (pH-value and electrical conductivity) of slaughter turkeys were measured after being stunned in a V-shaped tunnel in an increasing carbon dioxide (CO₂)-atmosphere compared to a gas mixture of CO₂ and argon (Ar) under practical conditions in a commercial slaughterhouse in order to assess the turkey's state of consciousness. Stick blood was analysed for stress parameters (lactate, catecholamines, corticosterone).After CO₂-only-stunning, 77% of the turkeys had closed eyes and 61% of the birds had their eyes shut after being stunned with CO₂&Ar. Only one bird showed an answer to the interphalangeal reflex (after CO₂&Ar-stunning). Lower values of blood stress parameters were found after CO₂-only-stunning, e.g. 37 nmol/l corticosterone (CO₂&Ar) in comparison to 28 nmol/l (CO₂-only-stunning). We determine that CO₂-only-stunning seemed to be more advantageous in this approach but future constructural improvements will be important to optimize this stunning system.     

Examination of the prevalence of skin injuries in debeaked fattened turkeys

Within the framework of a cooperative research project, turkey health as well as numerous aspects of animal welfare were examined in various intensive commercial farms with varying rearing forms. The present study demonstrates the prevalence of skin injuries concerning living animals as well as carcasses of slaughtered turkeys of both sexes. Although all turkeys were debeaked, prevalences of skin injuries at a value of 12.8% with male turkeys and 13.8% with female turkeys could be found at the age of 16 weeks. Within the scope of medically inspections skin injuries were mainly established in the head region, especially the snood as well as in the region of the back. By means of their clinical picture pecking wounds and scratch injuries could be distinguished. Skin lesion produced primary as a result of scratching the skin surface, could be enlarged by the animal itself or by conspecifics by beak pecking, especially after bleeding, in spite of debeaked upper beak. Injuries in the head region, especially of the snood, could be explained mainly as a result of pecking by conspecifics by reason of their clinical picture and were found mainly in male turkeys. Skin injuries in the region of the back, especially at the coxal tuberosity, were identified primarily as scratch marks. They were found mainly in female turkeys. A statistically significant correlation of the injury prevalence to particular husbandry parameters discussed in the literature as "predisposing" or "limiting" factors (e.g., population density, light regime or offer of employment material) could not be established in this study. At the meat inspection fresh scratching injuries at the chest and the hind legs were diagnosed most often. Especially fresh injuries of the carcass point to a misguided behaviour of the staff concerning animal handling during loading and transport which is not conform to animal welfare.