Effective Stunning Research Articles

Towards the humane slaughter of decapod crustaceans: identifying the most effective indicators of insensibility following electrical stunning

Decapod crustaceans provide a valuable food source worldwide, both through wild capture and captive rearing. They are also used extensively in scientific research, both as subjects for the investigation of basic biological processes and as model organisms for the detection of environmental changes. There is now an increasing acceptance that decapod crustaceans are sentient, and legislation is being introduced in numerous countries to ensure crustacean welfare when they are harvested or held captive. Moreover, methods for the humane slaughter of these animals are being developed, and of these electrical stunning is a prime candidate. Optimisation of electrical stunning is underway for a range of commercially-exploited or scientifically-important species, and the present study contributes to that process by examining further crab (Carcinus maenas) and lobster (Homarus gammarus) species using a rigorous neurophysiological approach. By recording nerve activity in both the central and peripheral nervous systems, we have found that electrical stunning with a standard commercial instrument arrests nerve activity in both these species at all levels: sensory, motor and central, rendering the animals neurologically insensible. This methodology is the most direct and effective way to establish if insensibility is successfully achieved. However, ultimately the routine monitoring of effective stunning in commercial and laboratory settings will have to depend on simple, yet reliable physiological or behavioural indicators, following their calibration against neurological methods. Monitoring heartbeat is used widely to establish metabolic activity, locomotory performance, agonistic interactions and responses to environmental conditions. We have therefore assessed the potential to use cardiac activity as an indicator for the state of sensibility. We recorded the heartbeat in both C. maenas and H. gammarus before and after electrical stunning, but find that in many cases even though nerve activity has ceased both centrally and peripherally, cardiac activity actually continues (though at a reduced rate) for a substantial time (>1h). The heartbeat is therefore not a reliable indicator of the state of sensibility, making it an unsuitable indicator of effective stunning. Possible reasons for these findings, and ways to validate behavioural measures that may be more appropriate for routinely establishing effective electrical stunning, are discussed.

Animal Welfare during Transport and Slaughter of Cattle: A Systematic Review of Studies in the European Legal Framework.

Literature related to European transport and slaughter processes were included in this systematic review. The publication period is limited to the past twelve years since the European Animal Welfare Transport Regulation was enacted in 2009. Three different databases were used. The final screening resulted in the inclusion of 19 articles in this review. When handling cattle during transport and slaughter, personnel have an important impact and may inflict stress on the animals. Other factors, such as the group composition and health status prior to transport, can have a strong negative effect on animal welfare. At the abattoir, constructional conditions and the resulting environmental influences can have a negative impact on welfare as well. These include increased noise levels due to the lack of noise dampening and changing light conditions. Stress in cattle can be assessed, e.g., by measuring stress hormones or heart rate. Effective stunning is an important welfare-relevant step in the slaughtering process. Some signs of unconsciousness, such as immediate body collapse or absence of the corneal reflex, can be easily assessed. Expertise and continuous training of all personnel involved are important measures in stress reduction.

The effects of electrical stunning on the nervous activity and physiological stress response of a commercially important decapod crustacean, the brown crab Cancer pagurus L.

Increasing attention is being paid to the welfare of decapod crustaceans. Legislation exists for their humane slaughter in several countries and this is being debated in others. Electrical stunning may have potential for humane slaughter of crustaceans in some circumstances, although scientific data on the effectiveness of electrical stunning when applied to various species are limited. Assessment criteria for effective stunning have so far been based mainly on behavioural assessments, but these do not always reflect neural insensibility. In this study direct recordings of neural activity, both centrally and peripherally, have been used to provide more direct measures of the state of sensibility. We have also examined whether electrical stunning acts as a physiological stressor, using measures of haemolymph L-lactate. Experiments were performed on a commercially important decapod species, the brown crab Cancer pagurus L. Spontaneous activity within the CNS was arrested by electrical stunning, which is an indication of loss of sensibility. There were also specific effects on the peripheral nervous system, with loss of responsiveness to sensory stimulation, rendering the animals unresponsive to external stimuli, and a failure of motor activation. All these effects were apparent immediately after a 10s stun, and persisted for as long as tested (4h) indicating that the animals were also killed by the procedure. No autotomy of limbs occurred. Haemolymph L-lactate was found to be no greater following electrical stunning than after handling and sampling alone, and both were significantly lower than values reached in a range of environmental and commercial situations. For all these reasons we find that electrical stunning may meet criteria for humane slaughter of C. pagurus.

Head-Only Stunning of Turkeys Part 2: Subjective and Objective Assessment of the Application of AC and DC Waveforms.

Simple SummaryIn this study, we investigated various types of application of head-only electrical stunning to turkeys, in order to improve the effectiveness of the stunning process. We used recordings of physical responses and of electroencephalograms (EEGs) to assess effectivity of stunning and various waveforms: alternating current (AC) and pulsed direct currents (DC). Depending on the waveforms, voltages between 125 and 250 V produced an effective stun in turkeys in this study.Electrical stunning is likely to remain an important stunning method for turkeys at slaughter. The purpose of this study is to understand the application of various waveforms of alternating current (AC) and pulsed direct currents (DC), head-only, to turkeys and to improve the effectiveness of handheld stunning of turkeys. We evaluated the effectiveness of stunning by documenting physical responses and recording electroencephalograms (EEGs). For the assessment of physical responses, the stunning voltage was varied depending on the proportion of animals effectively stunned at a certain voltage level. If all turkeys in a group of 10 were stunned, the voltage was decreased, and the next group was stunned. This was repeated until not all turkeys showed signs of being effectively stunned. The experiment was then repeated at the voltage level just above the one that showed incomplete effective stunning. The effects of the stunning on the EEG recording was assessed in 16 turkeys to measure the occurrence of epileptiform EEGs, in 14 turkeys to assess epileptiform EEGs after neck-cut (bleeding), and in 14 turkeys to assess the effect of increased voltage and reduced frequency on epileptiform EEGs. Assessing EEGs in a laboratory setting contributes considerably to the understanding of electrical stunning procedures. Voltages between 125 and 250 V, depending on the waveform assessed, were effective in producing an effective stun in turkeys in this study.

Head-Only Stunning of Turkeys Part 1: The Minimum Voltage Necessary to Break Down the Inherent High Resistance.

Simple SummaryPre-slaughter stunning is required for the humane slaughter of turkeys. For the head-only electrical stunning to be effective, the impedance (resistance) in the tissue of the head of the animal between the two electrodes must be overcome by the level of the voltage used. We have assessed the most appropriate voltage to effectively overcome the impedance and provide an effective stun, and that is also safe for the operator to use. Sinusoidal AC at 150 V and 50 Hz was considered to fulfil those requirements and was used for further testing.Pre-slaughter stunning is required for humane slaughter. For turkeys, head-only electrical stunning is most often used by small scale producers. To ensure immediate and effective stunning, the impedance (resistance) of the tissue of the head of the animal situated between the two electrodes needs to be overcome swiftly. The impedance is a function of the voltage and decreases non-linearly with increasing voltage. In this paper, we describe a method to assess the minimum voltage needed at which the impedance no longer decreases, that is likely to produce an effective stun. For ethical reasons, gas stunned, electrically naïve turkeys were used to measure impedance at various levels of voltage and current. Several combinations of voltage and frequency, alternate current (AC), direct current (DC) and pulsed DC, were identified that would be sufficient to achieve the maximum decrease in the impedance, and therefore would allow the highest current and the most effective stun. A minimum, expressed as Root Mean Squared voltage, of 150 V and 50 Hz. would be required in AC, 175 V in pulsed DC at 30% cycle (150 at 50% cycle), and 225 V if voltage spikes of very short duration were used. Sinusoidal AC applied at 150 V, 50 Hz was selected for further testing.

Electrocution as an alternative euthanasia method to blunt force trauma to the head followed by exsanguination for non-viable piglets

BackgroundOn farms, the currently approved and most widely practised method of euthanising non-viable piglets is blunt force trauma to the head followed by exsanguination. However, the use of this method is criticised due to public perceptions and aversion to the methodology by caretakers. Therefore, electrocution after electrical stunning was examined as an alternative approach in 80 hybrid piglets. Initially, electrocution was simulated with finite element analysis using a computer piglet-model, where current density in the heart was visualised and size and position of the electrodes were defined. The following step investigated electrical parameters for electrocution in anaesthetised piglets; first, with a constant voltage power source and then with a constant current power source. The electrical stunning was examined using the constant current supply. Finally, the results of electrical stunning and electrocution were verified in 25 healthy piglets with a body weight between 1 and 2 kg. Unconsciousness was proven by testing palpebral, corneal and nociceptive reflexes. Time of death was confirmed by electroencephalography (EEG) and electrocardiography (ECG) records.ResultsStunning succeeded with the preset of 1.3 A and 50 Hz, placing the electrodes on both sides of the head between the eyes and ears using different timespans between 8 and 20 s. Prolonged electrical flow resulted in reduced paddling movements after the epileptic seizure, and allowed undisturbed reflex tests and installation of electrodes for EEG and ECG recording during electrocution. Using 0.75 A and 400 Hz, pin-shaped electrodes were first positioned on both sides of the chest for 5 s, followed by a break of 20–30 s and a second current flow, whereby the electrodes were placed above the withers and the sternum for 5 s. Cardiac arrest and an isoelectric EEG were induced within 3 min after the onset of the electrical flow through the chest. The most obvious indicator of effective stunning and electrocution was termination of rhythmic breathing. Piglets with cardiac arrest showed only single gasps lasting up to 3 min after electrocution.ConclusionsThe evaluated stunning and electrocution protocol might ease concerns about timely piglet euthanasia. However, this should be verified in non-viable piglets to exclude influencing factors like dehydration and diseases.

The Impact of Deviation of the Stun Shot from the Ideal Point on Motor Paralysis in Cattle.

Simple SummaryThe welfare of cattle during slaughter predominantly depends on the ability of the stunner to induce immediate collapse and insensibility. The main aim of the study was to evaluate the accuracy of the stun shot under commercial conditions and the success rate of inducing motor paralysis in relation to the distance of the placement of the stun shot from the ideal point on the cattle skull. The results show that as the deviation in the stun shot position increases, the failure to induce motor paralysis in cattle significantly (p < 0.01) increases.The effect on motor paralysis of a deviation in the stun shot placement from the ideal point on cattle skulls was monitored in 627 bovine animals (271 bulls and 356 cows) stunned with a captive bolt during slaughter in a slaughterhouse. The number of animals that experienced motor paralysis and the necessary fall of the animal in the stunning box were recorded after the stun shot. Subsequently, the position of the stun shot was measured on the skull of the slaughtered cattle in relation to the ideal point on the skull, and at a deviation from the ideal point, the quadrant on the skull in which the bullet was located was determined. The results show that with the increasing distance of the placement of the stun shot from the ideal point on the skull, the incidence of failure to induce motor paralysis in cattle increases significantly (p < 0.01) from 2.4% (within 3 cm of deviation) to 72.2% (at deviations > 7 cm). There was a significant increase in the failure to induce motor paralysis in bulls as well as in cows, but this was more frequent in bulls regardless of the magnitude of the deviation from the ideal point (with the exception of a distance greater than 7 cm where the chances of inducing motor paralysis in bulls and cows are equally low). The incidence of failure to induce motor paralysis in cattle was not dependent on the placement of a stun shot in various quadrants on the skull. With the increasing deviation in any direction from the ideal point, the likelihood of effective stunning of cattle decreases. The results are important from the animal welfare point of view of the slaughter of cattle, and demonstrate the necessity of optimum placement of the stunning shot on the bovine skull in order to achieve the successful motor paralysis of cattle during their stunning at the slaughterhouse.

Cattle stunning with a penetrative captive bolt device: A review.

The captive bolt device has been used for stunning cattle at abattoirs for more than 100years and is now one of the stunning devices used most widely. The aim of this review article was to assess the effects that are decisive during cattle slaughter on the quality of stunning with the use of a captive bolt stunning device. The basis of effective stunning is the use of a suitable type of device, with the speed of the bolt and the kinetic energy corresponding to the anatomical parameters of the slaughtered animal. The importance of the regular cleaning and maintenance of stunning devices and monitoring of the effectiveness of stunning goes without saying. The immediate loss of sensibility in the animal must occur after the first shot. The effectiveness of the stunning process can be quantified by regular monitoring of the behavior of animals after stunning with an emphasis on the loss of reflexes (corneal reflex, regular breathing, attempts to regain physiological posture) and checks on the shot location on the skulls of slaughtered animals.

Effect of EU electrical stunning conditions on breast meat quality of broiler chickens

Electrical stunning is still the main stunning method used worldwide in commercial poultry plants. The stunning procedures in water bath stunners affect both bird welfare and meat quality attributes. The European Union (EU) Council Regulation 1099/2009 on the protection of the animal at the time of killing established the minimum current flow through an individual bird at a specified frequency to assure an effective stun that must last until the bird's death. The aim of this study was to compare the effect of the application of different stunning current flows on the prevalence of hemorrhages (classified as 1 = no lesion, 2 = moderate, and 3 = severe lesion) and some quality traits (pHu, color, drip and cooking losses, and shear force) of chicken breast meat. A total of 12 flocks of broiler chickens, each equally divided into light, medium, and heavy sizes, was submitted either to the stunning condition usually adopted before the entry into force of the current EU regulation (90mA/bird, 400Hz) (OLD) or to that enforced by it (150mA/bird, 400Hz) (NEW). Overall, the prevalence of severe hemorrhages dramatically increased in the NEW group in comparison with the OLD one (55vs. 27%; P < 0.001) and particularly in heavy-sized birds (72vs. 25%; P < 0.001). In general, meat quality attributes were not affected by the stunning conditions with the exception of drip loss that resulted lower in NEW than OLD birds (1.01vs. 1.27; P < 0.001). In conclusion, the adoption of a higher current flow, as suggested by the EU regulation to protect animals at the time of killing, increases the prevalence of breast hemorrhages while maintaining meat quality traits with a possible beneficial effect on water holding capacity of fresh meat.

Effects of ambient temperature and water vapor on chamber pressure and oxygen level during low atmospheric pressure stunning of poultry

The characteristics of the vacuum used in a low atmospheric pressure stunning system to stun (render unconscious) poultry prior to slaughter are described. A vacuum chamber is pumped by a wet screw compressor. The vacuum pressure is reduced from ambient atmospheric pressure to an absolute vacuum pressure of ∼250 Torr (∼33 kPa) in ∼67 sec with the vacuum gate valve fully open. At ∼250 Torr, the sliding gate valve is partially closed to reduce effective pumping speed, resulting in a slower rate of decreasing pressure. Ambient temperature affects air density and water vapor pressure and thereby oxygen levels and the time at the minimum total pressure of ∼160 Torr (∼21 kPa) is varied from ∼120 to ∼220 sec to ensure an effective stun within the 280 seconds of each cycle. The reduction in total pressure results in a gradual reduction of oxygen partial pressure that was measured by a solid-state electrochemical oxygen sensor. The reduced oxygen pressure leads to hypoxia, which is recognized as a humane method of stunning poultry. The system maintains an oxygen concentration of <5% for at least 2 minutes, which ensures that birds are irreversibly stunned. Calculated pump down (pressure versus time) data match experimental data very closely because the programmable logic controller and the human machine interface enable precise and accurate control. The vacuum system operates in the turbulent viscous flow regime, and is best characterized by absolute vacuum pressure rather than gauge pressure. Neither the presence of broiler chickens nor different fore-line pipe designs of four parallel commercial systems affected the pressure-time data. Water in wet air always reduces the oxygen concentrations to a value lower than in dry air. The partial pressure of water and oxygen were found to depend on the pump down parameters due to the formation of fog in the chamber and desorption of water from the birds and the walls of the vacuum chamber.

Assessment of stun quality after gunshot used on cattle: a pilot study on effects of diverse ammunition on physical signs displayed after the shot, brain tissue damage and brain haemorrhages

AbstractMoving the slaughter process from the abattoir to the animals’ familiar environment has the potential to reduce pre-mortal stressors to a minimum and contribute considerably to improved animal welfare at slaughter. On-farm stunning and killing of free-range cattle via gunshot became legal in Germany in November 2011, including for commercial sale of the meat. As an effective stun is essential for maintaining animal welfare until the animal dies, the goal of this study was to assess the feasibility of delivering an instantaneous and deep stun by an accurate frontal gunshot at cattle. Thirty free-range cattle (Galloway, German Angus) were shot with five different combinations of rifles and bullets. A stun-quality protocol was developed to assess musculoskeletal, optical and respiratory signs displayed after the shot. Key signs, such as failure to collapse, corneal reflex, spontaneous blinking, eyeball rotation or eyeball movement, distinct vocalisation and rhythmic breathing were not evident in 29 of the 30 cattle. Dissections of the heads were used to detect penetration depth of the projectile as well as evaluate brain tissue damage and brain haemorrhage caused by the shot. Tissue damage was marginal and not related to the ascertained level of stun quality. Brain haemorrhages assumed to be sufficient for causing a deep stun were detected in 25 out of 30 cattle. Accurate shot placement turned out to be more important than the application of a certain calibre. However, it was considered crucial for safety reasons that the projectile should remain within the cranial cavity. As long as there are high levels of accuracy, gunshot was considered to be an effective stunning method with the potential of maintaining high standards of animal welfare until death occurs.

Effectiveness of tail-first dry electrical stunning, followed by immersion in ice water as a slaughter (killing) procedure for turbot (Scophthalmus maximus) and common sole (Solea solea)

To protect the welfare of fish at slaughter, these animals should be rendered unconscious and insensible prior to killing. Furthermore, the state of unconsciousness must be long enough to allow killing without recovery. The objective of this study was to determine the stunner settings for effective tail-first dry electrical stunning of turbot (Scophthalmus maximus) and common sole (Solea solea). The fish were separated in two batches (B1 and B2). The turbot and sole in B1 were subjected to a short tail-first stun lasting for 1s and after 1min of recovery to a second, longer (20s) stun. The fish in B2 were exposed to a single long (20s) stun, which was tail-first in sole, but head-first in turbot. The short stun was applied to verify that the loss of consciousness was instant (i.e. within 1s), whereas the long stun (followed by immersion in ice water) was performed with the aim of showing that it is feasible to kill the fish without recovery. Loss of consciousness and sensibility were assessed using electrophysiological (EEG and ECG) and behavioural parameters.After administering a current of 2.39±0.91Arms by applying 125.5±0.6 Vrms (100Hz) in turbot and 1.22±0.68 Arms by applying 152.4±0.5Vrms in sole for 1s, 25 out of 26 turbot and 9 out of 10 sole in B1 exhibited EEG patterns showing that the fish were rendered unconscious instantly.The long tail-first exposure of turbot in B1 to 3.88±1.26 Arms for 1s, followed by 1.44±0.41 Arms for 19s, followed by immersion in ice water, led to an irrecoverable stun in 21 out of 22 fish, whereas the long head-first stunning of turbot in B2 (n=13) resulted in passing 1.27±0.40 Arms for 1s and 0.65±0.21 Arms for 19s through the fish and no recovery during chilling. After the long, tail-first exposure of sole in B1 (n=9) and B2 (n=22) to 1.18±0.49 Arms for 1s+0.35±0.22 Arms for 19s, and 1.20±0.59 Arms for 1s+0.36±0.15 Arms for 19s, respectively, none of the fish regained consciousness during the chilling.We conclude that the tail-first electrical stunning, followed by immersion in ice water can be developed into an effective stunning and killing method for turbot and sole.Statement of relevanceThe paper expedites stunning of turbot and sole in practice.

Hygiene and Welfare Evaluation of Pigs Slaughtered in Agritourisms.

The slaughtering procedures at agritourism farms must be carried out in accordance with the general and hygiene requirements of Regulations (EC) No 852 and 853/2004. In addition, regional laws define minimum requirements allowing some flexibility. Piglets and finishing pigs are the most frequently slaughtered animal in Sardinian agritourism farms. The aim of the present survey was to evaluate: the general and hygiene requirements of outbuilding slaughterhouses in agritourisms; the animal welfare indicators; the microbial contamination of piglets and finishing pigs carcasses. Six agritourisms outbuilding slaughterhouses – EU-approved – were investigated. General and hygiene requirements of outbuilding slaughterhouses and animal welfare indicators of 68 piglets and 5 finishing pigs were evaluated by mean of a checklist. The following parameters were determined on 45 piglets and 5 finishing pigs carcasses: i) pH 1 and 24 h after slaughter, and ii) carcass surface microbial contamination by non destructive method (sponge) on the following sampling sites: ham; back (adults); belly; jowl (adults). Aerobic colony count (ACC; ISO 4833:2003), Enterobacteriaceae (EB; ISO 21528-2:2004), Salmonella spp. (ISO 6579:2002), Listeria monocytogenes (ISO 11290-1:1996 and 11290-2:1998) were also tested. All the plants except one have two separate rooms, for clean and dirty zones, stunning and bleeding operations being frequently carried out on open air. The piglet scalding was carried out in hot water bowls, and hair removal by singeing. Animal welfare signs revealed the following aspects: handling: hoisting prior to stunning, vocalizations (41%); stunning: not individual access to box, repeated shocks (4%), mean voltage 135.6 V, mean current for head-only electrical stunning 0.78 A; indicators of not effective stunning: palpebral reflex (24.2%), corneal reflex (12.8%), vocalizations (15.4%); bleeding: conscious and sensitive animal shackling (53.8%). Results of carcass evaluation showed, for piglets and adult pig respectively: i) pH: pH1=6.21±0.25 and 6.18±0.22; pH24=5.66±0.17 and 5.49±0.11; ii) ACC: 4.11±0.64 and 4.63±0.42 (log10 CFU/cm2, mean±standard deviation); iii) Enterobacteriaceae prevalence of 81.6% (2.55±0.80) in piglets and 100% (3.22±0.90) in adults. Salmonella spp. and Listeria monocytogenes were not detected in any of the samples. General requirements of outbuilding slaughterhouses in agritourisms are suitable to produce meat in compliance with hygienic rules, considering the low risk level. Results of Enterobacteriaceae levels of finishing pig carcasses were not in compliance with the EC Regulation No 2073/2005. Training of personnel is compulsory and can improve the stunning and bleeding procedures.

Cone restraining and head-only electrical stunning in broilers: Effects on physiological responses and meat quality

Two experiments were conducted to evaluate a new electrical stunning system for broilers. The objective of the first experiment was to evaluate the behavioral, neural, and physiological responses of 27 broilers after head-only electrical stunning while their bodies were restrained in cone-shaped holders. In the second experiment, quality of meat from 30 broilers after head-only electrical stunning in a cone-shaped restrainer was compared with that from 30 broilers stunned in a conventional water bath. Broilers were restrained in the cone with their heads positioned to facilitate a correct stun, followed by a neck cut by hand. After stunning, each broiler displayed a tonic phase, followed by minimal brain activity during bleeding. On average, heart rate was 258 ± 51 beats/min before stunning. The heart was observed to malfunction after cutting. According to the correlation dimension analyses, the score remained low. Within a confidence limit of 95%, taking into account the number of birds with a reliable electroencephalogram (n = 27), the chance of an effective stun and exsanguination with all broilers lies between 0.90 and 1.00 using a sinusoidal AC current of 264 ± 29 mA (∼130 V). After a brief learning period, operators were able to easily position the broilers in the cone in a commercial setting. The pH after chilling was 0.5 units lower (P < 0.05) in the head-only stunned group compared with the group stunned in a conventional water bath. After head-only stunning, 60% of breast fillets showed no blood splashes and 3% showed severe blood splashes compared with 20 and 27% after conventional water bath stunning. No differences in temperature and color were observed between the 2 groups. It is concluded that broilers could be restrained in a cone, followed by correct head-only stunning, neck-cutting, and unconscious shackling afterward under laboratory and commercial slaughterhouse conditions. When this procedure was used, meat quality was better compared with broilers stunned in the conventional water bath.

Evaluación de la eficacia del método de insensibilización por electronarcosis en porcinos

SUMMARY National and international sanitary legislation state the guidelines that regulate the slaughter of animals for human consumption purposes due to its implications in animal welfare and meat quality. The aim of this study was to evaluate the slaughter in the swine population of a commercial slaughter plant using behavioural and management indicators. A total of 1,341 pigs were monitored. The electrical stunning method was assessed using behavioural indicators in the stunning box (jumps, falls, vocalizations, slips); the signs of consciousness (blink reflex, righting reflex, vocalizations, pain response) and organizational variables (stunning to bleed interval, collapse of the animal, position of the electrodes, application time of the tongs and effectiveness of the stunning procedure). Vocalizations (26.8%) were the behavioural response most commonly found and they were associated to the presence of falls and slips (P < 0.01), making evident certain problems related to the handling of the animals and the infrastructure design. Effective stunning was accomplished in 20.6% of the cases. The righting reflex was positively associated to the presence of all the other signs of consciousness (P < 0.01). The duration of the application of the tongs, the stunning to bleed interval and the electrical specifications were not adequate, evidencing several failures in the standardization of the process. It is strongly recommended to incorporate the behavioral and management indicators to audit routinely the efficiency and animal welfare standards during pig slaughter, as well as promoting training of the staff to guarantee a humane procedure.

Scientific Opinion on the electrical requirements for waterbath stunning equipment applicable for poultry

The Commission requested that EFSA review relevant new scientific references on electrical stunning of poultry and to recommend, if necessary, new electrical requirements applicable for waterbath stunning equipment. A systematic literature review was conducted to determine those electrical parameters that would deliver an effective stun so that birds would be rendered unconscious and insensible until death. Inspection data from slaughterhouse inspections conducted both in Member States in and non-Member States were included. Many of the published studies did not allow a comprehensive analysis due to different study designs and incomplete data. There are few observational studies in abattoirs to determine the numbers of birds that are effectively stunned, however, the inspection data from the Food and Veterinary Office (FVO) did not identify major problems but, for practical reasons, they used non-EEG (electro-encephalogram) methods to ascertain the effectiveness of a stun. At the present time, an EEG is the most reliable indicator of unconsciousness and insensibility. Clinical somatosensory indicators are not as reliable. The aim of a stunning system is to achieve a 100% effective stun, and the most effective electrical parameters in use can achieve an effectiveness of up to 96% as measured using EEG ascertainment methods (100% were reported as unconscious using non-EEG methods). It is recommended that the Regulation should indicate minimum current for each bird, frequency and current type as well as the wave characteristics - duty cycle and waveform. There should be better surveillance and monitoring of the electrical parameters in use at abattoirs and, in addition, methods that allow the accurate measurement of actual electrical current flowing through each bird should be further developed. Research on effective stunning should be validated by the measurement of EEG activity and related to clinical measures that are easier to use in practice.

Survey of the incidence of post-stun behavioural reflexes in electrically stunned broilers in commercial conditions and the relationship of their incidence with the applied water-bath electrical parameters

AbstractDespite recent technological advances, stunning efficiency of broilers in commercial plants is still questionable and a major public concern. The aim of this survey was to assess the electric water-bath parameters used in poultry processing plants, establish practical ways for the assessment of stunning efficiency in these conditions, link their incidence to the applied current and propose methodology for the online evaluation of the effectiveness of electrical water-bath stunning. A total of 5,378 broilers were assessed randomly for signs of post-stun recovery at 4, 8, 13 and 25 s post-water-bath exit (WBE) through corneal reflex, rhythmic breathing, head shake and escape behaviour on three processing lines. The electric water-bath parameters used did not meet the recommended current and frequencies for effective stunning. No rhythmic breathing was detected with any of the birds at 4 s post water-bath exit, while this reflex returned by 8 s in some birds. Broilers that had their necks cut had a significantly lower incidence of breathing compared to those that missed the neck cutter. The electric water-bath stunners that were tested did not abolish the corneal reflex where 38.4% of birds tested positive, at 4 s post WBE. Pulsed DC-stunned birds that missed the knife had a significantly higher incidence of positive corneal reflexes than those that had their necks cut. Head shake was present on 26.7% of the birds when assessed at 25-30 s post WBE. The trends in incidence of behavioural reflexes with time post WBE may be used for the assessment of stunning efficiency, particularly on birds that miss the knife, but none of the assessed indicators could unequivocally demonstrate unconsciousness.

Head-cloaca controlled current stunning: assessment of brain and heart activity and meat quality

1. Behavioural and neural responses of 65 broilers to head-to-cloaca electrical stunning were evaluated and meat quality was assessed on two groups of 25 broilers stunned either head to cloaca, or in a conventional water bath method. 2. On the EEG recordings, a general epileptiform insult was observed when applying a current of 100 mA (100 Hz) or 70 mA (70 Hz) for 1·5 s. This general epileptiform insult shows a tonic, clonic and exhaustion phase followed by spikes of alpha, beta, theta and delta waves with duration of on average 34 ± 12 s and 39 ± 23 s respectively. These birds may have been unconscious for 20 s or longer, according to the correlation dimension analyses. 3. The heart rate decreased significantly (P < 0·05) after stunning and recovered after 60 s. 4. Within a confidence limit of 95%, taking into account the number of animals with a reliable EEG, the chance of an effective stun of all broilers lies between 0·9 and 1·0 with a current of 70 mA (100 Hz for 1·5 s; n = 28) and with 100 mA (100 Hz for 1·5 s; n = 27). 5. The shear force of breast fillets was slightly lower (P < 0·01) 4 d post mortem compared with the conventional water bath stunned group (set at 100 mA, 100 Hz for 10 s). The percentage of fillets and legs without blood splashes was higher, and the percentage with severe blood splashes lower-to-none, for carcases stunned head-cloaca. 6. It can be concluded that broilers are effectively stunned with the head-cloaca method by using a controlled current of 70 mA or 100 mA for 1·5 s. The fillets and legs of bird stunned head-cloaca showed fewer blood splashes in the muscles compared with birds stunned in a conventional water bath.

Factores que influyen en la emesis post-aturdimiento en bovinos

To determine the effect of lairage duration, stunning effectiveness, type of commercial cattle, and ruminal content consistence on carcass contamination by emesis at slaughter between stunning and exsanguinations (stun-stick interval), data were analysed from 9,446 animals in Federal Inspection and Municipal slaughterhouses (P1, P2, P3, P4). Lairage duration was classified in three categories: T1) less than 3 h, T2) major than 3 h and lesser than 12 h, and T3) major than 12 h. Stunning was classified as effective and no effective. The consistence or ruminal content was identified and evaluated as watery, semi-watery and dense. Was recorded at P1, number of heads and lungs contaminated, data analysis by X2. On P2 y P3, the frequencies obtained were analyzed with logistic regression. In P4 data were disposed in frequency tables and analysed by X2. Long lairage time (T3) with ineffective stunning increased 1.73 times the risk to observe carcass contamination. At the long lairage time (T3), emesis increased (P<0.05), when ruminal content was watery (62.9 % vs 12.5 y 24.6 %). The emesis was similar between male and female (P=0.10, 10.07 %). There was not relationship (P=0.58) between repose time and type of commercial cattle in emesis. It is concluded that high lairage duration, no effective stunning, and watery and semi-watery content ruminal consistence, increased the emesis in stun-stick interval bovine slaughtering.

Evaluation of head-only electrical stunning for practical application: Assessment of neural and meat quality parameters

Behavioral and neural responses of 47 broilers to head-only single-bird electrical stunning were evaluated using cone-shaped restrainers in which the broilers were suspended by their feet. Meat quality assessment was performed on 2 groups of 25 broilers stunned using the head-only method or a conventional water bath method. Hemorrhages were quantified by a visual grading system. On electroencephalogram recordings, a general epileptiform insult was observed when a set current of at least 190 mA (˜100 V, 50 Hz) was applied for a duration of 0.5, 3, or 5 s. This insult showed a tonic phase, followed by a clonic phase and an exhaustion phase, after which the birds recovered. On the basis of visual observation, these birds may have been unconscious for approximately 30, 44, or 65 s. According to correlation dimension analysis scores, these durations were 18, 12, and 16 s, respectively. Within a confidence limit of 95%, taking into account the number of birds with a reliable electroencephalogram, the chance of an effective stun lies between 0.95 and 1.00 with an average current of 190 ± 30 mA. After stunning, the electrocardiogram revealed fibrillation. The heart rate decreased significantly (P < 0.05) after stunning but recovered thereafter. The pH after chilling was (P < 0.05) lower in the group stunned head only compared with the water bath group. The percentages of fillets free of blood splashes were 80% in carcasses of head-only-stunned birds and 16% in carcasses from broilers stunned in the commercial water bath. It was concluded that broilers were insensible and unconscious after head-only electrical stunning using pin-electrodes. Because of the risk that broilers can rapidly regain consciousness after stunning, cutting the neck immediately after stunning is recommended. It is also recommended that the head-only equipment be developed further for practical application and commercial use.