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.     

Carcase and meat quality in ducks killed with either gas mixtures or an electric current under commercial processing conditions

1. The feasibility of killing 7-week old Peking ducks with gas mixtures and their effects on carcase and meat quality were evaluated and compared with killing in electrical waterbath under commercial conditions. 2. The prevalence of carcase appearance defects and broken bones in the carcases and haemorrhaging, pH, colour, cooking loss and texture of breast muscles were determined. 3. Ducks can be killed within 3 min by exposure to either 90% argon in air or a mixture of 30% carbon dioxide and 60% argon in air. 4. Gas or controlled-atmosphere killing of ducks, whilst they are still in their transport containers, would eliminate some of the welfare concerns associated with the conventional electrical waterbath stunning systems, without adversely affecting carcase and meat quality.     

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.     

Effect of rate of induction of carbon dioxide anaesthesia on the time of onset of unconsciousness and convulsions

The effect of different rates of induction of carbon dioxide anaesthesia on the time to loss of consciousness was investigated in broilers and hens. In experiment 1, 24 and 17 broilers, respectively, were exposed to 45 per cent carbon dioxide within 8 or 18 seconds (accession time). In experiment 2, 18 to 20 broilers and hens were exposed to either 35, 45, 55 or 65 per cent carbon dioxide within 8 seconds. The results indicated that, in general, the rate of accession is more critical than the final concentration of carbon dioxide; however, in 35 per cent carbon dioxide an exposure time of longer than 5 minutes is required to kill the birds. The time to sustained eye closure, time to onset of clonic and tonic convulsions and the duration of convulsive episodes were shorter in broilers than in hens. It is suggested that under commercial situations a final concentration of 55 per cent carbon dioxide would be suitable for killing broilers and hens.     

Water supply for Peking ducks--possible alternatives for bathing

In order to investigate possible advantages of open water drinkers such as troughs and bells in the intensive husbandry of ducks, we evaluated in this study the effect of open water systems on the behavior and health of peking ducks. In this investigation six fattening trials each with 1152 Cherry Valley Peking ducks were analyzed. The average fattening period was 47 to 49 days. The ducks were kept on straw in six standardized compartments each 32 qm with 192 ducks. 25% of the compartment with perforated grid, with one of the tested water systems. In contrast to pens with nipple-drinkers only, the ducks in pens with open water troughs/showers had the opportunity to exhibit their natural drinking behavior and water associated activities in accordance with the animal welfare requirements. In the free-choice pens the open water systems were significantly preferred, and over a 24-hour period the ducks in watering areas with open water troughs showed higher activity. Limiting the access to the open water systems to eight, four or two hours per day led to an increased use per time unit. Ducks with access to nipple drinkers only showed a significantly higher percentage of plugged up nostrils than animals from pens with open water drinkers. Open water drinkers had also a positive impact on the plumage condition.     

An investigation into the batch killing of turkeys in their transport containers using mixtures of gases

This study was carried out under commercial conditions to investigate the feasibility of killing turkeys while they were still in their transport containers, with a mixture of gases, and to compare the effects of this method and electrical stunning on the prevalence of carcase downgrading conditions and haemorrhages in the breast muscles. The results showed that turkeys could be readily killed while still in their transport containers by using either anoxia induced with 90 per cent argon in air or hypercapnic anoxia induced with a mixture of 30 per cent carbon dioxide and 60 per cent argon in air, and that the prevalence of carcase-downgrading conditions and haemorrhages in the breast muscles was lower after killing the turkeys with the gases.     

Nutritional requirements of meat-type and egg-type ducks: what do we know?

The demand for duck meat, duck eggs, and associated products is increasing each year. Classic and modern selection programs have been applied to enhance the economic traits of ducks to satisfy the requirements of consumers and enhance the incomes of producers. The nutritional requirements of unselected ducks may not be adequate, however, to fulfill the potential productivity performance of modern birds, including both meat-type and egg-type ducks. In particular, an imbalanced diet is associated with low productive performance and signs of nutritional deficiency(if insufficient nutrients are supplied), as well as with high feed costs and manure problems that reflect flock health and welfare(if excessive nutrients are supplied). Thus, the main aim of this review is to summarize the results of previous studies that estimated the nutrient requirements of meat-type and egg-type ducks in order to evaluate current knowledge and to identify further issues that need to be addressed. In addition,the results obtained in previous studies are compared in order to understand how to lower commercial feed costs,fulfill the genetic potential of selected ducks, protect the environment from pollution, and satisfy the welfare and health needs of ducks.     

Avian influenza outbreak management: action at time of confirmation, depopulation and disposal methods; the 'Belgian experience' during the H7N7 highly pathogenic avian influenza epidemic in 2003

Eradication of H5 and H7 influenza in a positive flock will include mass depopulation of birds, containment and inactivation of the virus in the carcasses and litter, and decontamination of the facility. A quick response is desired in the event of a disease outbreak. Ideally, birds should be depopulated within 24 h after detecting the virus. Mass depopulation of birds must be performed in a humane manner while minimizing human health and biosecurity risks. In the framework of the European legislation, a number of methods are authorized for the killing of poultry for processing prior to marketing. However, during emergencies such as a disease outbreak, there are fewer options. The current most commonly used procedures for large-scale emergency depopulation of birds consist of exposing poultry to CO or CO(2) gas. Both gasses have been used in Belgium during the H7N7 crisis in 2003. The gassing procedures include whole house gassing, portable panel enclosures, cage cabinets, containers and polyethylene tent method. Whole house gassing requires sealing the house to prevent gas leakage and, using specialized equipment, introducing large volumes of gas evenly over the birds. All procedures are very labour intensive, create a biosecurity risk and require a large number of personnel. There are considerable region-to-region differences in emergency depopulation techniques and disposal of carcasses and infected material. Because of the differences in bird type and species, management, housing and stocking density, it is difficult to propose a depopulation technique that will be suitable for all circumstances. Safety of the human operators is an increasing concern with all H5 and H7 strains and in particular with the highly pathogenic H5N1 strain. Researchers and commercial poultry companies in the United States recently established that non-toxic water-based foam with a certain bubble size presents a practicable, effective and humane method for mass depopulation. Foam of the right bubble size creates an occlusion in the trachea of birds, causing a rapid onset of hypoxia. The foam that blankets the broiler house induces physical hypoxia - the same cause of death as the approved method using carbon dioxide gas (CO(2)). The article illustrates the different culling and disposal methods with a focus on the methods used during the 2003 H7N7 crisis in Belgium.     

Electrocution of pigs infected with notifiable diseases

In order to combat certain notifiable diseases eradication programs have been developed, which include the destruction of an infected or suspected herd. Experiments were conducted to develop a method for euthanasia of large numbers of pigs. The electrocution experiments under laboratory conditions were performed in a wooden sided box with a steel floor and a curtain of chains. When the pigs touched the chain curtain with their noses, they received a current flow which lasted for more than 2 seconds, and they developed cardiac arrest or fibrillation. The pigs which touched the chain curtain with their rumps vocalised and became recumbent immediately. An automatic electrocution unit was constructed with a conveyor (negative electrode) and 3 curtains of chains (positive electrodes). Over 6000 pigs infected with a notifiable disease were killed with the apparatus. Only 2 piglets younger than 1 week old were not killed by the current (1000 V, greater than 2 s.). From the point of view of animal welfare the automatic electrocution apparatus is an efficient method for killing large numbers of pigs (older than 1 week of age) infected with a notifiable disease.     

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.     

Investigation into the batch stunning/killing of chickens using carbon dioxide or argon-induced hypoxia

Three hundred and twenty broilers were stunned for 2 minutes in batches of 10 per crate in four treatments: 45 per cent carbon dioxide; 55 per cent carbon dioxide; 2 per cent oxygen, or 5 per cent oxygen presented as air diluted by argon. The number of survivors and the time to resumption of consciousness were recorded using the time to eye opening and response to comb pinching as indicators of consciousness. In 45 per cent and 55 per cent carbon dioxide and 2 per cent oxygen, 28, none and eight birds, respectively, survived out of 100 in each group. In 5 per cent oxygen the birds were still fully conscious after a 2 minute exposure period, and the test was discontinued. The time to recovery could be rapid after stunning in both the gases. It is suggested that a concentration of 55 per cent carbon dioxide or less than 1 per cent oxygen are required to kill broilers within a 2 minute exposure period, and that care should be taken to ensure that there is sufficient turbulence within the stunning chamber to avoid air pockets being trapped between the birds.     

Electrocution of pigs infected with notifiable diseases

Summary

In order to combat certain notifiable diseases eradication programs have been developed, which include the destruction of an infected or suspected herd. Experiments were conducted to develop a method for euthanasia of large numbers of pigs.

The electrocution experiments under laboratory conditions were performed in a wooden sided box with a steel floor and a curtain of chains. When the pigs touched the chain curtain with their noses, they received a current flow which lasted for more than 2 seconds, and they developed cardiac arrest or fibrillation. The pigs which touched the chain curtain with their rumps vocalised and became recumbent immediately.

An automatic electrocution unit was constructed with a conveyor (negative electrode) and 3 curtains of chains (positive electrodes). Over 6000 pigs infected with a notifiable disease were killed with the apparatus. Only 2 piglets younger than 1 week old were not killed by the current (1000 V, > 2 s.). From the point of view of animal welfare the automatic electrocution apparatus is an efficient method for killing large numbers of pigs (older than I week of age) infected with a notifiable disease.     

北京鸭肌肉生长抑制素基因多态与屠体性状关系分析

肌肉生长抑制素（Myostatin,MSTN）基因在发育和成熟的骨骼肌中特异表达,对肌肉具有负调控作用。应用聚合酶链式反应单链构象多态性（PCR-SSCP）的方法,对6周龄北京鸭2个群体（Z2系和Z4系）共200个个体Myostatin基因5’调控区进行SNP分析,并对所发现的单核苷酸多态性与胴体重、胸肌重、腿肌重、全净膛重、皮脂重、腹脂重、骨架重、胸肌率、腿肌率、皮脂率、腹脂率进行了关联分析。结果发现,A1/A2位点基因型（AA和AB型）对6周龄Z2系和Z4系北京鸭的腹脂重（P＜0.05）和胸肌重（P＜0.10）有显著影响,因此可以将Myostatin基因作为影响北京鸭Z2系和Z4系腹脂重和胸肌重的候选基因。     

Welfare implications of gas stunning pigs: 3. the time toloss of somatosensory evoked potential and spontaneous electrocorticogram of pigs during exposure to gases

Changes in the spontaneous electrocorticogram (ECoG) and somatosensory evoked potentials (SEPs)were recorded in 12 pigs in each of three gas killing treatments. The treatments were 90% argon in air with 2% residual oxygen; a mixture of 30% carbon dioxide and 60% argon in air with 2% residual oxygen; or 80–90% carbon dioxide in air. The mean times to loss of SEPs were 15, 17 and 21 s, respectively. The mean time to loss of SEPs recorded during killing with a high concentration of carbon dioxide was significantly longer than those recorded for the other two gas killing treatments (P <0.05). Slow waves (high amplitude and low frequency) appeared on average 15 s after exposure to argon. In some pigs killed with the carbon dioxide-argon mixture, a decrease in the frequency of electrical activity was apparent, although slow waves did not appear during killing with a higher concentration of carbon dioxide. A suppressed ECoG (reduction in amplitude of signals) was recorded at 22 and 20 s respectively, during exposure to the carbon dioxide-argon mixture and 80–90% carbon dioxide in air, but the onset of ECoG suppression could not be determined exactly during exposure to 90% argon in air. The time to onset of an isoelectric ECoG was 54, 39 and 32 s after exposure to argon, carbon dioxide-argon mixture and a high concentration of carbon dioxide, respectively. The mean time to the onset of an isoelectric ECoG during exposure to argon was significantly longer than that recorded for the other two gas killing treatments (P <0.05). Based on the time to loss of SEPs, it is concluded that during killing with a high concentration of carbon dioxide, pigs would have to endure a moderate to severe respiratory distress induced with this gas for a considerable period of time prior to the loss of brain responsiveness. Argon-induced induced anoxia appears to be the first choice from a welfare point of view for killing pigs, based on its lack of aversive properties and its effectiveness in rapidly abolishing brain responsiveness. A mixture of 30% carbon dioxide and 60% argon in air is considered to be more humane than using a high concentration of carbon dioxide, as the time to loss of brain responsiveness is similar to that using 90% argon in air.     

Culling of animals in large herds, experiences from the Netherlands

The outbreaks of classical swine fever in 1997-1998 and foot- and mouth-disease in 2001 provided a lot of experiences in the culling of animals. These experiences, as well as the aspects of animal welfare and public acceptance are described. In the future these experiences will help to carry out culling in a more efficient way including improved aspects of animal welfare and public acceptance.     

生长前期北京鸭生物素需要量及脚裂症的初步探究

本文旨在研究不同生物素水平对生长前期北京鸭生长性能的影响,并对生物素缺乏症———脚裂症进行初步探究。试验选用体重相近的1日龄雄性北京鸭480只,随机分成10组,每组6个重复,每个重复8只鸭。各组分别添加0、0.03、0.06、0.09、0.12、0.15、0.18、0.21、1.50 mg/kg生物素及3 g/kg蛋清粉。试验期4周。结果表明,不同生物素水平对1～21日龄北京鸭平均日采食量和平均日增重有显著影响(P<0.05),但对料重比没有显著影响(P>0.05)。统计发现,各组表现出不同程度的脚裂症,其中3 g/kg蛋清粉组最为严重;生物素添加水平高于0.15 mg/kg时,脚裂症得到有效缓解。不同生物素水平对28日龄北京鸭肝脏磷脂含量和血清谷丙转氨酶(ALT)和天冬氨酸氨基转移酶(AST)活性有显著影响(P<0.05)。通过数据分析得出,以平均日增重为衡量指标,采用直线折线和二次曲线模型估测生物素适宜需要量分别为0.180和0.202 mg/kg,并初步判断脚裂症与脱水存在一定的关系。     

A brief summary of European legislation regarding animal welfare

An overview of the current European legislation concerning animal welfare is given. The legal requirements concern the housing and care of production animals (poultry, calves and swine), the transport of animals and the killing of animals (not only in slaughterhouses, but also in case of contagious animal disease outbreaks). General information concerning the principles and contents of European pieces of legislation as well as detailed information concerning requirements for individual animal species is given. Furthermore, other elements concerning animal welfare such as castration of piglets, ritual slaughter and animals used for experimental purposes are also reviewed. Finally, some recent initiatives in the field of animal welfare are mentioned and useful links are provided for finding the various legislative acts and additional supportive information.     

不同生物素水平对北京鸭前期生长性能影响及后期缺乏症观察

选用体重相近的1日龄雄性北京鸭512只,随机分成8组,每组8个重复,每个重复8只鸭。研究不同生物素水平对1~14日龄北京鸭生长性能的影响,以及进行后期生物素缺乏症的观察。结果表明:提高日粮中生物素水平,1~14日龄北京鸭日采食量和日增重也随之提高(P<0.05),料重比没有改善(P<0.05)。以日增重为衡量指标,通过直线折线模型分析,初步确定生物素适宜添加水平为0.186 mg/kg。北京鸭生物素缺乏症病变依次表现:眼部>羽毛>腿部>肝脏,伴发脂肪肝肾综合症(FLKS)。     

1～14日龄北京鸭苏氨酸需要量的研究

试验采用2×5双因子完全随机试验设计,研究苏氨酸水平对1～14日龄北京鸭生产性能的影响,进而探讨1～14日龄北京鸭苏氨酸需要量。选取480只体重相近的1日龄健康的W系雄性北京鸭,随机分为10个处理,每个处理6个重复,每个重复8只北京鸭。试验日粮共设2个蛋白水平,分别为14%和20%;5个苏氨酸水平,分别为0.50%、0.58%、0.66%、0.74%、0.82%,各试验日粮的代谢能和其它必需氨基酸添加量一致。试验期为14d。研究结果表明:日粮蛋白质水平与苏氨酸水平产生明显的互作效应,且蛋白质水平与苏氨酸水平对1～14日龄北京鸭采食量、日增重、料重比影响均显著(P0.01)。在高蛋白质水平下,以采食量和日增重为评价指标,分别建立其与苏氨酸需要量的回归方程,得出均呈二次曲线变化,且1～14日龄北京鸭最佳苏氨酸需要量分别为0.688%、0.737%。在低蛋白质水平下,日增重和日采食量均随着苏氨酸水平的升高而升高,未出现下降或平台期,因此,低蛋白质水平下的苏氨酸需要量高于高蛋白质水平下的苏氨酸需要量,苏氨酸需要量与蛋白质有关。     

Evaluation of a breast support conveyor to improve poultry welfare on the shackle line

A breast support conveyor has the potential to improve bird welfare by avoiding the need to invert and suspend broilers by their legs as they move from the point of shackling to entry into the electric waterbath. To evaluate its effect on welfare under commercial conditions, a breast support conveyor was installed under the conventional shackle line of a small poultry processing plant. A structured assessment of the behaviour of the birds indicated a significant decrease in struggling and wing flapping at the point of shackling, on the straight conveyor and at entry into the waterbath. This resulted in a lower prevalence of red wing tips and bruising in the first wing joint. The shackle line and conveyor in this installation, however, passed around a 90° corner, which appeared to cause more disturbance to the birds on the conveyor than to comparable birds suspended from shackles in the traditional manner. The results indicate that a breast support conveyor has the potential to improve bird welfare on straight shackle lines and that, because struggling activity and duration following shackling are reduced, the time between shackling and stunning could also be reduced using this method, further improving bird welfare. Breast support conveyors should not be used when the shackle lines have sharp bends.