E. Lambooij

Slaughter of poultry during the epidemic of avian influenza in the Netherlands in 2003

During an outbreak of avian influenza in the Netherlands in spring 2003, the disease was controlled by destroying all the poultry on the infected farms and on all the farms within a radius of 3 km. In total, 30 million birds were killed on 1242 farms and in more than 8000 hobby flocks, by using mobile containers filled with carbon dioxide, mobile electrocution lines and by gassing whole poultry houses with carbon monoxide or carbon dioxide. Observations of these methods were used to compare their effectiveness and capacity, and their effects on the welfare of the birds. Gassing whole poultry houses had a much greater capacity than mobile equipment, and catching live birds to bring them to a mobile killing device caused extra stress and could cause pain due to injuries inflicted when catching and handling them. Gassing whole poultry houses with carbon monoxide requires strict safety regulations and, therefore, gassing with carbon dioxide was considered preferable. However, this method is not suited to all types of housing, and in these circumstances mobile killing devices were a useful alternative.

Welfare aspects of live chilling and freezing of farmed eel (Anguilla anguilla L.): neurological and behavioural assessment

Abstract The overall objective of the study was to evaluate a slaughter method of eels, which consisted of chilling until their body temperature was Firstly, 19 eels with an average live weight of 758±44 g were restrained and equipped with EEG, ECG electrodes and a temperature sensor inside the body. Then, they were placed in the ice water. Indices for the induction of unconsciousness and insensibility were the appearance of theta and delta waves and no response on pain stimuli, which disappeared at a body temperature of 8.0±2.1 °C after 12±5 min in 15 eels. The responses to pain stimuli did not disappear in three eels. Within a confidence level of 95%, the percentage of eels that is not effectively stunned during the procedure in ice water of n =14) to 7±4 ( n =11) and became irregular during cooling down. When placed in the brine water of −18 °C, the EEG showed rapid and extreme depolarisation of the membranes, which started after 27±17 s ( n =18). The ECG showed fluttering of the heart in all eels. None of the eels recovered after this procedure. For 10 eels with an average live weight of 128±27 g, it was observed that the body temperature decreased from 17.1±0.6 to 4.0±0.5 °C in the ice water. After 15 min in the brine water of −16.1±2.2 °C, the body temperature decreased to −3.1±2.3 °C. Finally, three groups of seven eels and eight single eels were placed in ice water of −0.0±0.1 °C. The observation of unrestrained eels revealed four phases. Animals were (1) swimming around in the water, (2) attempting to escape from the ice water, (3) pressing their nose to the wall or corner while showing clonic muscle cramps, and finally (4) breathing only, while all other muscle activity was totally suppressed. Afterwards, they were transferred to cold brine at −18 °C, and none of the eels recovered. The eight control eels, which were transferred to water at 18 °C, swam around, except for one that was lying in an S-shape position at the bottom. After 570 and 605 s, two eels tried to escape from the box. The obtained results show that the eels, which were transferred from water at 18 °C to ice water, might be stressed, a specific behaviour and an irregular heart rate were observed. From an animal welfare point of view, it is therefore not recommended to stun eels by live chilling. Moreover, at least 5% of the eels will not be stunned at a body temperature of

Animal welfare concerns during the use of the water bath for stunning broilers, hens, and ducks

European legislation demands that slaughter animals, including poultry, be rendered immediately unconscious and insensible until death occurs through blood loss at slaughter. This study addressed requirements for stunner settings (i.e., voltage, wave oscillation frequency) and response parameters (i.e., applied current, behavior) affecting effective water bath stunning. An inventory of current electrical stunning practice was performed in 10 slaughterhouses in the Netherlands. Thereafter, measurements were performed using a single-bird water bath to examine the effects of stunner settings based on the average technical settings observed in the slaughterhouses. Responses were recorded at 50, 400, and 1,000 Hz on broilers and hens and at 50 and 400 Hz on ducks under controlled laboratory conditions. Effects of voltage settings (broilers: 100 to 400 V; hens: 150 to 300 V; ducks: 150 to 400 V) on current levels (broilers: 45 to 444 mA; hens: 40 to 219 mA; ducks: 64 to 362 mA) and consciousness (response to pain stimulus) were recorded immediately after stunning. Brain and heart activity was monitored using electroencephalogram and electrocardiogram technology. Results show that effective stunning using the conventional water bath almost exclusively produces blood splashing in broilers. Effective stunning current levels did not differ significantly between broilers, hens, and ducks effectively stunned hens tended to require lower currents. Effective stuns at higher frequencies resulted in higher currents. Similar input voltage (V) levels (within and between bird type) resulted in significant variation (P < 0.001) in current levels (mA) required for an effective stun, indicating variability in electrical impedance between individual birds. Body weight and bird type did not affect the probability of an effective stun. Multi-bird water bath usage does not ensure effective stunning and technical adjustments can result in detrimental effects on meat quality. Future legislation should consider wave form, relationships between frequency and current allowing for individual impedance variation and effects on meat quality while safeguarding animal welfare.

Castration of piglets under CO2-gas anaesthesia

It has become common practice in pig fattening production systems to castrate young boar piglets without the use of anaesthesia. In this study, we examined whether or not CO2 gas is capable of inducing an acceptable anaesthetic state during which castration can be performed. The first step was to identify the most promising CO2/O2 mixture. Based on the results from this first experiment, a mixture of 70% CO2 + 30% O2 was chosen for further investigation as a potential anaesthetic during the castration of young piglets. Thereby, it was established whether the duration and depth of anaesthesia were acceptable for castration where the animal has to be insensible and unconscious. Physiological effects were assessed based on electroencephalogram (EEG) and electrocardiogram (ECG) measurements, blood gas values and behavioural responses. During the induction phase, the only typical behaviour the piglets exhibited when exposed to the 70/30 gas mixture was heavy breathing. All piglets (n = 25) lost consciousness after approximately 30 s according to the EEG. Heart rate decreased slowly during the induction phase, a serious drop occurred when piglets lost their posture. Immediately after this drop, the heart rate neared zero or showed a very irregular pattern. Shortly after loss of posture, most animals showed a few convulsions. None of the animals showed any reaction to castration in behaviour and/or on the EEG and ECG. On average, the piglets recovered within 59 s, i.e. EEG returned to its pre-induction pattern and piglets were able to regain a standing position. After 120 s, heart rate returned to pre-induction levels. In order to explore the usage range of CO2 concentration, 24 piglets were exposed to 60% CO2 + 20% O2 + 20% N2 for up to 30 s after loss of consciousness (as registered on EEG), and castrated after removal from the chamber. Sixteen of the 24 animals showed a reaction to the castration on the EEG. To establish the maximum time piglets survive in 70% CO2 + 30% O2, five piglets were placed in this mixture for 3 min. Two of them died. After that, four piglets were placed in this mixture for 2 min after unconsciousness, one died after 2 min. It was concluded from this study that it is possible to anaesthetise piglets with a mixture of 70% CO2 + 30% O2, but that there are limits to its safety in terms of CO2 concentration and duration of exposure. Before implementation for practical use, further research is essential to assess the limits of gas concentration and exposure times.

Evaluation of captive needle stunning of farmed eel (Anguilla anguilla L.): suitability for humane slaughter

Abstract In the study, 53 eels with a live weight of 700 to 800 g were restrained and equipped with EEG and ECG electrodes before stunning. The eels were mechanically stunned by a captive needle pistol using a shooting pressure of 8 bar and an air injection of 3 bar during 1.5 s. The behaviour was observed during and after stunning. Indices for the immediate induction of unconsciousness and insensitivity were the appearance of theta and delta waves tending to an iso-electric line, i.e. no brain activity. The duration of these waves averaged 11±8 s ( n =32) on the EEG. Another nine animals showed directly after stunning no brain activity. Due to severe clonic cramps five animals were stunned twice. The ECG showed fluttering of the heart configuration immediately after stunning in all eels. It was concluded that within a confidence level of 95%, taking into account the number of animals with a reliable EEG ( n =42), at least 93% of the eels were effectively stunned by a correctly positioned captive needle pistol. It was easy to stun eels with a captive needle pistol using air pressure; however, more research is needed for the development of a restraining and stunning device suitable for use in practice.

Pain behaviour after castration of piglets; effect of pain relief with lidocaine and/or meloxicam

Behavioural responses and the effect of lidocaine and meloxicam on behaviour of piglets after castration were studied. A total of 144 piglets of 2 to 5 days of age were allocated to one of six treatments: castration (CAST), castration with lidocaine (LIDO), castration with meloxicam (MELO), castration with lidocaine and meloxicam (L + M), handling (SHAM) and no handling (NONE). Behaviour was observed for 5 days after the procedure, growth until weaning was recorded and characteristics of the castration wound noted. MELO piglets showed significantly (P < 0.05) more no pain-related behaviour than CAST and LIDO at the afternoon after castration, and were not significantly different from SHAM and NONE. LIDO piglets showed an increase (P < 0.001) in tail wagging, lasting for 3 days. This increase was not seen in L + M piglets. The occurrence of several behaviours changed with age, independent of treatment. A treatment effect on growth was not found. Wound healing was rapid in all treatments, but thickening of the heal was observed in several piglets, suggesting perturbation in the cicatrization process. Our study showed a pain-relieving effect of meloxicam after castration. Local anaesthesia resulted in piglets performing more tail wagging during the first few days after castration, which was prevented by administering meloxicam in combination with local anaesthesia.

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.

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.

Fish welfare assurance system: initial steps to set up an effective tool to safeguard and monitor farmed fish welfare at a company level

The objective was to take a first step in the development of a process-oriented quality assurance (QA) system for monitoring and safeguarding of fish welfare at a company level. A process-oriented approach is focused on preventing hazards and involves establishment of critical steps in a process that requires careful control. The seven principles of the Hazard Analysis Critical Control Points (HACCP) concept were used as a framework to establish the QA system. HACCP is an internationally agreed approach for management of food safety, which was adapted for the purpose of safeguarding and monitoring the welfare of farmed fish. As the main focus of this QA system is farmed fish welfare assurance at a company level, it was named Fish Welfare Assurance System (FWAS). In this paper we present the initial steps of setting up FWAS for on growing of sea bass (Dicentrarchus labrax), carp (Cyprinus carpio) and European eel (Anguilla anguilla). Four major hazards were selected, which were fish species dependent. Critical Control Points (CCPs) that need to be controlled to minimize or avoid the four hazards are presented. For FWAS, monitoring of CCPs at a farm level is essential. For monitoring purposes, Operational Welfare Indicators (OWIs) are needed to establish whether critical biotic, abiotic, managerial and environmental factors are controlled. For the OWIs we present critical limits/target values. A critical limit is the maximum or minimum value to which a factor must be controlled at a critical control point to prevent, eliminate or reduce a hazard to an acceptable level. For managerial factors target levels are more appropriate than critical limits. Regarding the international trade of farmed fish products, we propose that FWAS needs to be standardized in aquaculture chains. For this standardization a consensus on the concept of fish welfare, methods to assess welfare objectively and knowledge on the needs of farmed fish are required.

Head-to-Cloaca Electrical Stunning of Broilers

This study was performed to identify the electrical current and exposure duration that would instantaneously render broiler chickens unconscious at slaughter when using a head-to-cloaca water bath stunner. The water in which the head was immersed was one electrode, and a steel-coned or cutaneous U-shaped electrode penetrating the cloaca was the other electrode. When an electrode penetrating the cloaca was used, a 640-Hz sinusoidal current induced a tonic-clonic phase on the electroencephalogram that lasted for 10 +/- 3 s and an exhaustion phase that lasted for 34 +/- 12 s. The heart rate was 375 +/- 39 beats/min before stunning. After stunning, the electrocardiogram revealed fibrillating for 429 +/- 58 s, after which the heart activity stopped. When a U-shaped electrode was placed on the skin at the cloaca, the same phenomenon was induced. A general epileptiform insult was induced when using a pulsed alternating square wave current of 33 mA (peak 60 V, 600 Hz, and a duty cycle of 50%), which lasted, on average, for 25 s (n = 25). When the broilers were bled within 14 s after stunning, they remained unconscious and the heart activity stopped after 237 +/- 103 s. We concluded from this experiment that broilers were effectively stunned with an average current of 111 mA (50 V, 640 Hz, sinusoidal alternating current) for 1 s when using a water bath in which the head of the broiler was immersed in water, with the water being one electrode and a steel electrode penetrating the cloaca or placed around it being the other electrode. Energy use could be reduced when an alternating pulsed square wave is used when the broilers are stunned, by using a current of approximately 33 mA (peak of 60 V, frequency of 600 Hz, and a 50% duty cycle).