1. Slaughter of farm animals
Module 22
Slaughter of farm animals

2. Summary of content Human versus animal needs Slaughter as a ‘process’
Methods and mechanisms
Examples and issues
The effectiveness of legislation aimed to protect animals at slaughter
This module will outline issues of animal use in the following areas:
Human versus animal needs
Slaughter as a ‘process’
Methods and mechanisms
Examples and issues
The effectiveness of legislation aimed to protect animals at slaughter.

3. Learning objectives
To illustrate issues surrounding the slaughter of animals
To identify humane methods of slaughter which promote best practice and protect the welfare of animals at the time of their slaughter
To identify legislative protection for animals at the time of slaughter
Learning objectives:
To illustrate issues surrounding the slaughter of animals
To identify humane methods of slaughter which promote best practice and protect the welfare of animals at the time of their slaughter
To identify legislative protection for animals at the time of slaughter.

4. Human and animal needs
The consumption of meat is a part of the dietary culture of many people
To supply meat to urban populations, the centralised commercial slaughter of farmed animals is now common
Despite the industrialisation of slaughter, huge numbers of farmed animals are killed locally by farmers themselves for their communities
The consumption of meat is a part of the dietary culture of many people.
To supply meat to urban populations, the centralised commercial slaughter of farmed animals is now common. This means that huge numbers of animals are transported from farm or production units to the place of slaughter. The transport of animals is discussed in module 20.
Despite the industrialisation of slaughter, huge numbers of farmed animals are killed locally by farmers themselves for their communities. The issues surrounding subsistence slaughter will be discussed in further slides, and include poor regulation of the slaughter process, little or no training for slaughter and use of methods which have not changed for hundreds of years, or evolved in line with developments in the knowledge of ‘best practice’.

5. Wherever animals are slaughtered, some principles can be applied
Humans may wish to eat meat
Animals have some basic needs – one of which is not to suffer at the time of their death
Principles
The wishes of the humans should not override the basic needs of the animals
The ‘benefit’ to the people should ‘justify’ the ‘cost’ to the animals
Wherever animals are slaughtered, some principles can be applied:
Humans may wish to eat meat. This wish may partly be a basic requirement to consume protein, and humans, like all animals, do have a requirement for amino acids. However, in many cultures, and by vegetarians in many societies, this need can be met without eating animal-derived protein. The wish to eat meat is cultural and based on preference rather than on an absolute need for animal protein.
Animals have some basic needs – one of which is not to suffer unnecessarily at the time of their death. Death is necessary for the ‘harvest’ of most animal protein – only egg and milk production allow harvest without the immediate death of the animal. In some cultures, animals are only killed after they have had a considerable period of life, but in most production systems, animals are killed as soon as they reach full, or adequate, size – for example, lambs, beef cattle, pigs and poultry are usually killed for meat before they reach maturity.
Principles:
The wishes of the humans should not override the basic needs of the animals
The ‘benefit’ to the people should ‘justify’ the ‘cost’ to the animals.

6. What is the potential ‘cost’ to the animal of slaughter?
The animal’s life will be ended
(some philosophers raise the issue of ‘quantity of life’)
The individual animal may experience fear, distress and pain during the slaughter process
Breakdown in established social groupings during transport and at markets
What is the potential ‘cost’ to the animal of slaughter?
The animal’s life will be ended, and some philosophers raise the issue of ‘quantity of life’ – i.e. is it immoral to truncate the normal life expectation of any animal; is life created with a normal pattern? If the animal is killed before it reaches maturity, is this an ethical issue?
For humans, if a life is shortened ‘prematurely’, this is viewed as a tragedy, whilst death in old age is considered as normal.
The individual animal may experience fear, distress and pain during the slaughter process. Many countries have attempted to regulate the processes of slaughter to try and reduce the potential for fear, pain and distress, but many societies have not, or are just beginning, to view this area as one for social and legal concern.
The natural make-up of animal groups (herds, flocks, etc.) is manipulated to produce animals of a required size or weight. Many production systems involve the grouping of same sex, same size and same age animals to produce a uniform product. This may mean that many animals never experience the social interactions which would have been normal in family groups for their species. For example, meat chickens (broilers) are hatched in mechanised plants and never experience interaction with any adult bird. Mixing of unfamiliar animals in markets and during transport can lead to aggressive interactions due to the breakdown of established social groupings.

7. Some farmed animals will be ‘home killed’ where they are reared
Hundreds of millions of chickens, ducks, turkeys, lambs, goats, cattle and pigs are killed each year on family and subsistence farms
Some farmed animals will be ‘home killed’ where they are reared – many hundreds of millions of chickens, ducks, turkeys, lambs, goats, cattle and pigs are killed each year on family farms. The ‘control’ of killing methods carried out by (possibly untrained) farmers may be a cause for concern.
Whilst commercial slaughter plants can invest in equipment, staff and training to achieve ‘best practice’, slaughter of animals on subsistence farms, whilst having a tradition that is many thousands of years old, has little or no ‘trained’ element. This type of slaughter also usually does not take advantage of improvements in techniques, some of which may greatly improve the welfare of the animals, as well as ease and safety for the slaughterman.

8. ‘Home’ killed animals
For animals killed on family farms and in isolated areas, slaughter methods have not changed for thousands of years:
Smaller animals (lambs, birds) are usually killed by exsanguination (neck cutting), or by decapitation
Larger species (cattle, sheep, goats, pigs) may be hobbled with ropes to allow neck cutting
Larger species are sometimes shot in the head and then bled out
For animals killed on family farms and in isolated areas, slaughter methods have not changed for thousands of years:
Smaller animals (lambs, poultry) are usually killed by exsanguination (neck cutting), or by decapitation
Larger species (cattle, sheep, goats, pigs) may be hobbled with ropes to allow neck cutting
Larger species are sometimes shot in the head and then bled out, or a poleaxe or puntilla (a knife used to sever the spinal cord) is used to immobilise the animal.
These methods use equipment which is universally available, and the use of restraint with hobbles, ropes, rings in the floor, or by tying the animal to posts or trees is necessary for larger species to protect the slaughterman.
In many places in the developing world, immobilisation of large ruminants (cattle, buffalo) is still carried out through the use of a sharp, pointed knife sometimes called a puntilla or Spanish pike. The knife is used to sever the spinal cord through the space (Foramen magnum) between the skull and neck position of the backbone. Upon inserting the knife and severing the spinal cord, the animal will collapse. It remains immobilised and the operators have easy access; however, the animals remain conscious until bleeding is complete. This practice should be discontinued, as it is not humane.
It is the potential for poor regulation of these processes, and little or no training for people carrying out subsistence slaughter, which raises concerns over the potential for ‘hidden’ suffering in animals slaughtered in these ways.

9. Many animals are taken to centralised commercial plants for slaughter
For these animals, the process of slaughter will involve transport
For most animals in developed countries, and for large numbers in nearly all parts of the world, before slaughter comes transport:
In many countries this transport is done with existing vehicles, trucks, trailers, boats, wagons and trains – which are often adapted ad hoc for this role, as they must also serve a number of other purposes. The result of this is that many animals are transported in unsuitable vehicles, often over long distances on difficult roads, in cramped conditions where they may become exhausted, dehydrated, overheated or be bullied by other animals travelling with them.
In systems where specialised transport exists, such as specific lorries for pigs, poultry, horses or cattle, the same conditions can apply if the road conditions are difficult, if the journey is long, if the stocking density – the number of animals in a given space – is high, if the animals are loaded and unloaded without care, or if they fight, or are exhausted by this process.
See module 21 for further details on transport.

10. Transport to slaughter has the potential to cause distress and suffering
Loading and unloading may be carried out with little regard for the animals’ usual abilities to climb ramps, slopes or stairs, or to jump out of lorries. When the vehicles are not adapted for animals, it may be necessary to coerce, lift, drag or pull animals onto vehicles (as seen in the photos) and many countries, recognising that some practices are potentially very damaging to the animals, have regulated the loading, unloading and transport conditions of animals to offer them some protection.
The cost of well-designed loading ramps, of adequately equipped lorries and boats, and of the length of time over which animals can be transported without (and with) water and food form the basis of many countries’ efforts to introduce best practice recommendations. Economic considerations almost always play a large part in these recommendations.

11. Meat quality can be reduced by stress at slaughter
Dark Firm Dry (DFD) beef resulting from pre-slaughter stress
Normal pork
Pale Soft Exudative (PSE) pork caused by stressful pre-slaughter handling conditions
Not only do animals have the potential to suffer, but meat quality can be reduced by stress during transport and at slaughter.
Some examples, illustrated by this slide:
Dark Firm Dry (DFD) beef results from pre-slaughter stress, which depletes muscle glycogen stores which are needed to produce the pH of normal meat. If glycogen is used up pre-slaughter, the pH changes required to cause the normal post mortem setting of meat do not occur and ‘dark cutting’ beef results. DFD is an indicator of stress, injury, disease or fatigue in the cattle before slaughter and reflects badly on the producer in terms of product quality.
Pale Soft Exudative (PSE) pork is caused by stressful pre-slaughter handling conditions in pigs. The same conditions of stress and fatigue which produce PSE may also induce ‘stress mortality’, acute death, during transport and in the lairage of pigs. PSE in pigs is caused by severe, short-term stress just prior to slaughter, for example, during off-loading, handling, holding in pens and stunning.

12. Lairage
Lairage is the holding of animals close to the slaughterhouse before slaughter.
During lairage, animals may be mixed with other unfamiliar animals and this may result in fighting. They may be subjected to tattooing or skin marking. They may have food withheld and may not be provided with bedding, water, shade, or the opportunity to carry out ‘coping’ behaviours such as escape, hiding, etc. to enable them to deal with bullying or high stocking densities in the lairage.
Many animals, particularly poultry, pigs and cattle, are subject to spraying with water to ensure the animals are clean, to cool them, and to provide them with distraction during lairage. The use of goads to move animals within lairages, particularly to move them to the final slaughter pen, or mechanised slaughter line, is common. All of these processes provide intense stimuli to the animals, in unfamiliar conditions, causing great potential for fear, distress and trauma.
Many commercial plants have made significant steps to improve lairage and handling systems for animals, and this move to ‘animal designed’ systems, led by such workers as Dr. Temple Grandin (see references) has the potential not only to improve conditions for the animals, but to reduce meat quality problems, and to improve the conditions of people working in these systems.

13. Exposure of the living to the dying
Many countries make it unlawful for living animals to be present in the same area as animals which are being butchered, but many countries do not, and in many slaughter plants, the dead and the living mix in the same space.
Some people believe that animals have the potential to be distressed by the sight, smell and sound of slaughter. Many countries have recognised this potential and have made it unlawful for an animal to be exsanguinated in the sight of another animal of the same species. Whilst it is conjecture that animals have the potential to fear death, it is apparent that many animals do not actually sense death, as evidenced by their failure to attempt to move away from recently killed animals. However, it may be prudent to assume that many species have very well-developed senses of smell, taste and social awareness which are likely to be profoundly influenced by the environment of slaughter, and it is likely to be humane to prevent living animals from being exposed to blood and animals that are being bled out.

14. In this case, to allow mechanised electrical stunning and bleeding
Restraint
‘Shackling’ of poultry is used in many automated slaughter systems. Whilst shackling may improve the efficiency of killing and, in some cases, thus reduce the time the animal may be subjected to the intense stimuli associated with the period just before slaughter, suspension by the legs raises separate issues of potential suffering.
The period for which poultry can be legally suspended before slaughter is regulated in many countries, but in others, birds may be suspended for very long periods if they are transported by, for example, bicycle, suspended by their legs.
Foot, leg, joint and meat quality effects are closely associated with shackle suspension, and by the setting up and control of automated slaughter equipment.
In this case, to allow mechanised electrical stunning and bleeding

15. Slaughter and killing
‘Slaughter’ is the killing of animals for food and is a ‘process’ – usually involving two stages:
Stunning – induction of unconsciousness in a ‘very short’ time
Killing – carrying out of a further process after stunning which makes physiological recovery impossible and leads to the death of the animal
‘Slaughter’ is the killing of animals for food and is a ‘process’ – usually involving two stages:
1) Stunning – induction of unconsciousness in a ‘very short’ time.
A ‘very short time’ would be classed by many as a time close to the time it takes the nervous system to register and interpret ‘nociceptive’ (painful /damaging) stimuli from the skin, muscle or blood vessels, and turn it into a signal for pain. In many species this has been measured by neuro-electrical means and is believed to be about 300ms (1/3 of a second) for profound painful stimuli. Thus, any process which can make an animal insensible in less than about 300ms has the potential to create an insensible state before the animal is able to detect the stunning process.
2) Killing – carrying out of a further process after stunning which makes physiological recovery impossible and leads to the death of the animal. This usually means the severing of major blood vessels causing circulating blood volume to collapse, or the irreversible destruction of the function of the brain and spinal cord.

16. Is ‘instant’ insensibility possible?
It is NOT practically possible to achieve ‘instant’ insensibility
It IS however possible to create unconsciousness in such a short time that the animal may be unaware that this has occurred
If a stunning process can induce unconsciousness in less than 300 ms this is considered to be IMMEDIATE
It is NOT practically possible to achieve ‘instant’ insensibility because the most commonly used methods (mechanical and electrical stunning) take a short time to cause changes in the activity of nervous tissue which will result in unconsciousness. However, as indicated in the previous slide, if insensibility can be achieved in less than about 300ms, then this provides the best possible outcome – an animal which becomes insensible before it has the time to register pain.
In many countries, this best practice state is phrased as IMMEDIATE insensibility – achieved in the least amount of time that is practical, by use of well-designed systems applied by professionals who understand the potential for suffering, understand the importance of what they are doing and take pride in doing it well.

17. Best practice
For any farmed animal the optimum method of slaughter involves:
Achieving an immediate state of unconsciousness
Followed by rapid progression to death
These principles are considered best practice, and are enforced by legislation in many societies
For any farmed animal, achieving an immediate state of unconsciousness, followed by rapid progression to death, is likely to be the optimum method for slaughter. These principles are considered best practice, and are enforced by legislation in many societies.
This immediate state of insensibility can be achieved by a number of means which will be described in the following slides. These include:
Captive bolt stunning
Percussive stunning
Electrical stunning
Gas stunning

18. Mechanisms for achieving an immediate stun (1)
Captive bolt stunning: If applied correctly, the captive bolt can induce insensibility within 150 ms
Captive bolt stunning:Transfer of energy via the skull, caused by a penetrating ‘bolt’, creates a wave of shock energy through the nervous tissue of the brain and the first part of the spinal cord. This energy wave causes depolarisation of nervous signals and induces insensibility in as short as 150 ms. The penetration of the bolt may also cause irreversible damage to the frontal cortex and midbrain, which helps to ensure the animal does not recover.
In most circumstances, the animal must be killed after captive bolt stunning by exsanguination. The stunned state achieved by captive bolt stunning is a temporary state, and killing must be carried out without delay to avoid any potential of return of sensibility.
An animal effectively stunned with a penetrating captive bolt pistol, as indicated by the presence of certain signs and the absence of others, has little possibility of brain function returning. Appropriate monitoring at all stages between stunning and sticking would ensure immediate detection and re-stunning on those few occasions when brain function was returning. When a captive bolt irreversibly stuns animals, sticking (with knife for exsanguination) has no role in terms of animal welfare; its only function is to relieve the carcass of blood. With effective initial stunning and subsequent monitoring, specifying a stun to stick interval appears unnecessary. (GREGORY, N., SHAW, F., 2000:Penetrating Captive Bolt Stunning and Exsanguination of Cattle in Abattoirs, Journal of Applied Animal Welfare Science. Volume 3, Number 3.)
In a study done to evaluate efficacy of penetrating captive bolt stunning of cattle, return-to-sensibility problems were attributed to storage of stunner cartridges in damp locations, poor maintenance of firing pins, inexperience of the stunner operator (i.e. shooting cattle too high on the forehead), misfiring of the stunner because of a dirty trigger, and stunning of cattle with thick, heavy skulls. (GRANDIN, T., 2002: Return-to-sensibility problems after penetrating captive bolt stunning of cattle in commercial beef slaughter plants. Journal American Veterinary Medical Assoc.Vol. 221: )

19. Positioning of the captive bolt weapon is important
To achieve an effective stun, positioning of the captive bolt weapon is important, and the animal should be restrained to allow accurate positioning. Restraint at stunning is a legal requirement in many countries. This requirement recognises the importance of accuracy in stunning to help ensure that the stun is effective and to help protect the animal from the severe suffering which may occur if poorly stunned.
To achieve restraint without the undue use of hobbles, tying or crushes, the design of handling facilities and races needs designs appropriate to the buildings, materials and skills available in each country and system. These should always be designed so that the animal suffers from the least amount of stress possible.

20. Captive bolt stunning position for cattle
The correct captive bolt stunning position for cattle is at:
The intersection point of two imaginary lines from the top of the eye, to the base of the horn buds.
Cattle must always be shot in the frontal position as the bones in the back of the head (poll position) are thicker and the energy transfer is poor.
The intersection point of two imaginary lines from the top of the eye to the base of the horn buds

21. Captive bolt stunning position for pigs
5cm (2 inches) above the eyes, slightly to one side of the mid line of the head (to avoid a thick ridge of bone), and at right angles to the forehead
Captive bolt positioning for pigs is:
5cm (2 inches) above the eyes, slightly to one side of the mid line of the head (to avoid a thick ridge of bone), and at right angles to the forehead.
Big boars and sows have a very ‘dished’ skull, and a high velocity (high energy) cartridge should be used in these animals because of the thick bone.

22. Captive bolt stunning position for sheep and goats without horns
Place the captive bolt weapon at the highest point on the top of the head and aim toward the angle of the jaw
Captive bolt stunning position for sheep and goats without horns:
Place the captive bolt weapon at the highest point on the top of the head and aim toward the angle of the jaw.

23. Captive bolt positioning for horned sheep or goats
Place the captive bolt just behind the ridge that joins the base of the horns and aim toward the mouth
Captive bolt positioning for horned sheep or goats:
Place the captive bolt just behind the ridge that joins the base of the horns and aim toward the mouth.

24. Captive bolt position for farmed deer
The muzzle of the captive bolt weapon should be placed at the intersection of an imaginary line between the eyes and the upper part of the base of the ears
Captive bolt position for farmed deer:
The muzzle of the captive bolt weapon should be placed at the intersection of an imaginary line between the eyes and the upper part of the base of the ears.

25. Mechanisms for achieving an immediate stun (2)
Percussive stunning: If applied correctly, this method induces insensibility within 150 ms
In percussive stunning, a mushroom shaped head transfers energy through the bones of the skull without penetrating the bone, and creates a wave of shock energy through the nervous tissue of the brain and the first part of the spinal cord. If applied correctly, this method induces insensibility within 150 ms.
This method has been used in religious slaughter, where stunning with penetration is perceived as being contrary to the requirement for the animal to be ‘intact’ at the time of exsanguination.

26. Percussion and concussion (often confused)
Percussion – ‘the forcible striking of one solid body against another’
Concussion – ‘temporary unconsciousness or incapacity due to a blow to the head’
Percussive stunners provide the force (energy) and concussion is the result
Percussion is ‘the forcible striking of one solid body against another’.
Concussion is ‘temporary unconsciousness or incapacity due to a blow to the head’.
Percussive stunners provide the force (energy), and concussion is the result.
Concussion is a temporary state, from which an animal may recover consciousness, and it is essential that a further process is performed to kill during the period of temporary unconsciousness induced by the stun.

27. Percussive stunning position for cattle
The head of the ‘knocker’ is placed at the intersection point of two imaginary lines from the top of the eye to the base of the horn buds
Percussive stunning position for cattle:
The head of the ‘knocker’ is placed at the intersection point of two imaginary lines from the top of the eye, to the base of the horn buds.
Some religious slaughter requires the use of a non-penetrating stunning method.

28. Percussive stun/kill for small farmed animals
In small animals, a suitable percussive stunner can induce immediate insensibility and death – this is known as stun/kill
Percussive stun/kill for small farmed animals:
For birds up to the size of a turkey, for rabbits and for small lambs and kids, a suitable percussive stunner can induce immediate insensibility and bring about severe damage to the nervous tissue in the brain which also results in death – this is known as stun/kill.

29. Mechanisms for achieving an immediate stun (3)
Electrical stunning: Electricity can act to induce uncoordinated electrical activity (epileptiform activity) in the brain which renders the animal unconscious
Electrical stunning:
Electricity can act to induce uncoordinated electrical activity (epileptiform activity) in the brain which renders the animal unconscious.
If this epileptiform activity can be induced in a time less than 300ms, then the animal is unlikely to feel the application of the stun.
This epileptiform activity is a temporary state, and, like the unconscious state induced by the mechanical means described, requires that the animal is then killed without delay, usually by exsanguination, before there is any potential for a return of sensibility.

30. Electrical stunning versus electrical killing
Electrical stunning brings about immediate insensibility and is considered best practice
Electrical killing, however, as carried out in destruction of dogs in some countries, does NOT ensure insensibility and may subject the animal to an agonising death
These two DIFFERENT uses of electricity should not be confused
Electrical stunning brings about immediate insensibility and is considered best practice because there is no potential for suffering when the animal is insensible.
Electrical killing, however, as carried out in the destruction of dogs in some countries, does NOT ensure insensibility and may subject the animal to an agonising death.
These two DIFFERENT uses of electricity should not be confused.
Electrical stunning relies upon delivery of electrical energy to the nervous tissues of the head.
The amount of electrical energy supplied to the brain depends upon the current and voltage, and this is influenced by the electrical resistance of the tissues in the head following Ohm’s Law:
I = V/R
(I = current delivered, V = voltage applied, R = resistance of tissues)
To reduce the resistance (R) good electrical contact between the stunning tongs and the skin is needed.
The electricity should pass directly across the head to ensure rapid insensibility.

31. Electrical stunning position for sheep and goats
Either side of the head between the eye and the ear.
Either side of the head between the eye and the ear

32. Electrical stunning position for pigs
Electrodes –either side of the head below the ears
Electrical stunning position for pigs:
Electrodes should be placed either side of the head below the ears.

33. Automated ‘water bath’ electrical stunning for birds
Electrical stunning is achieved by the head of each bird passing through a ‘water bath’
Birds are killed by automated ‘water bath’ electrical stunning:
Electrical stunning is achieved by hanging the birds upside down so that the head of each bird passes through a water bath – a trough containing water, in which electrical contact is made with the bird’s head.
Many billions of farmed poultry are killed annually by electrical stunning followed by exsanguination. Automated systems have the potential to cause significant suffering if they are not monitored to ensure that the systems function correctly and that all animals are stunned.
In water bath stunning, the following potential hazards should be regulated:
Pre-stun shocks: Birds may receive shocks from wet surfaces before the water bath. These shocks will not stun the bird but will be very painful. Close attention to design of systems is important.
Ineffective stunning: Poor contact with the water bath, due to small birds not making good contact with the water, poorly designed water baths, poor regulation of voltage/current leaving birds inadequately stunned.
Poor bleed out due to inadequate cutting of the blood vessels in the neck by automated equipment.

34. Automated electrical stunning has the potential for poor control
Any automated stunning system must be closely monitored to ensure that the animals are effectively stunned – non-stunned animals which enter the neck cutter will suffer a ‘poor death’.
In this picture, the duck on the left is lifting its head away from the water in the water bath stunner (the water fills the bottom of the picture). This duck will pass on to have its neck cut without being effectively stunned, and may, potentially enter the next stage in the process, the ‘scald tank’, without having been effectively stunned.
Systems such as this must be designed so that they are capable of modification and evolution to ensure that changes can be made to suit different animal sizes, species and behavioural characteristics. Rigid automated systems can lead to welfare problems through poor stunning, but well-designed systems operated by skilled personnel can create dramatic improvements in the welfare impact of the slaughter process.
Duck lifting head above water level – will not be stunned

35. Stunning and killing are not the same
A stunned animal is in a temporary state of unconsciousness from which it can potentially recover consciousness
The stunned animal must then be killed before there is any chance of recovering consciousness
Stunning and killing are not the same.
A stunned animal is in a temporary state of unconsciousness from which it can potentially recover consciousness. The stunned animal must then be killed before there is any chance of it recovering consciousness.
This applies to almost all stunning systems, where insensibility protects the animal from the potential pain and distress of the killing method, but this killing method must be applied without delay to ensure there is no potential for a return of sensibility.

36. Killing methods Exsanguination is the most common method
Of the killing methods used after stunning, exsanguination, or loss of an irrecoverable volume of blood, is the most commonly used because it not only kills the animal but also provides a carcass, and hence meat, with only a small amount of residual blood in the tissue.
Bleeding out is most commonly achieved by severing the major vessels in the neck (carotid arteries and jugular veins), which causes rapid loss of blood volume and collapse of brain and respiratory function.
Some stun/kill methods such as secondary cardiac arrest stunning in pigs and high frequency stunning in poultry do not demand exsanguination as the heart is stopped by these methods, and there is thus no possibility of recovery of consciousness.
Exsanguination is the most common method

37. Gas stunning
Poultry and pigs – high concentrations of CO2 or argon gas
At high concentrations, CO2 acts as an anaesthetic gas
Argon is not detectable (inert) and induces death by anoxia
Ethical and economic questions about these methods
Gas stunning is a stun/kill method in that the method not only initially stuns the animal, but also subsequently results in irreversible changes that result in the death of the animal.
For poultry and pigs, placing the animals in high concentrations of CO2 (carbon dioxide) or argon gas induces a stunned state followed rapidly by death from anoxia.
At high concentrations, CO2 acts as an anaesthetic gas, but there is a period of time before the induction of this stunned state during which the animal may find the sensory aspects of the gas (acidic, cold) aversive.
Argon is not detectable (inert, and hence not sensed by the animal) and induces death by anoxia. Because CO2 cannot accumulate in this atmosphere, the animal does not experience the ‘panic’ sensations due to low O2.
The aversive (unpleasant to the senses) effects of CO2 and the relatively high cost of argon have raised ethical and economic questions about these methods, but they are widely used in commercial slaughter of pigs and poultry.
These methods are not suitable for large species, or for heavily fleeced animals because, in large animals, application of gas is not practical, and for fleeced animals, the air held by the fleece prevents the stunning gas from reaching high enough concentrations.

38. Muslim slaughter
Muslim slaughter – Dhabh or Zabiha, can be carried out by any ‘sane’ Muslim (male or female) and produces Halal meat
Requirements – use of a sharp knife and utterance of Allah’s name at the moment the neck is cut
Muslim slaughter – Dhabh or Zabiha, can be carried out by any ‘sane’ Muslim (male or female) and produces Halal meat.
Requirements – use of a sharp knife and utterance of Allah’s name at the moment the neck is cut.
Qur’an Majeed ‘Taqwah’ requires that man is ‘kind, compassionate, merciful and charitable to all living beings’ and that followers of Islam should not eat:
Carrion, blood, pigs, animals not killed in the name of Allah, animals that die from a violent blow, from a fall, from goring or by being savaged by a wild animal.
It is likely that at the time these laws or recommendations were made, they represented sound public (and animal) health guidance, and may have also represented the best practice for that particular time and situation. In the past, religious edicts were taken as law by the public, and therefore many issues of public importance were embedded in religion.
However, changes in societies across the world, and advances in understanding of animal suffering and welfare now support new ideas of best practice, which many countries and societies have adopted. Unfortunately, because of the part in the Qur’an about not being allowed to eat animals killed by ‘violent blows’, captive bolt stunning has not been accepted by many Muslim communities.

39. Jewish slaughter
Jewish slaughter (Shechita) is carried out by a trained slaughterman (Shochet), licensed by the Rabbinic Commission, and produces Kosher meat
The animals must be healthy and without any prior injury
The knife is regularly sharpened, and severs the arteries and veins in the neck to cause death by exsanguination
Jewish slaughter (Shechita) is carried out by a trained slaughterman (Shochet) , licensed by the Rabbinic Commission, and produces Kosher meat.
The animals must be healthy and without any prior injury.
The knife is regularly sharpened, and severs the arteries and veins in the neck to cause death by exsanguination.
The concept of tsa’ar ba’alei chayim, the Torah mandate to avoid causing unnecessary harm to animals, promoted the initial reason for shechita slaughter.

40. Welfare issues of religious slaughter
The original concepts of Dhabh and Shechita slaughter were ‘best practice’ at the time of their introduction
Best practice now states that it is possible to bring about very rapid insensibility by stunning, after which death may be caused by bleeding out
Bleeding out alone is likely to cause a period of distress to the animal which is significantly longer than the distress caused by stunning
The original concepts of Dhabh and Shechita slaughter were best practice at the time of their introduction, but experience gained in the last century from around the world now promotes the current best practice concept that it is possible to bring about very rapid insensibility by stunning, after which death may be caused by bleeding out.
Bleeding out alone is likely to cause a period of distress to the animal which is significantly longer than the distress caused by stunning, and this is the basis for the use of stunning before bleeding out in many countries.
Many countries and societies, after debate, and based on the scientific evidence provided, have made commercial slaughter without stunning unlawful.

41. Effectiveness of animal welfare legislation in slaughter plants and on farm
May be ineffective as a result of poor enforcement due to:
Limited resources
Limited training of slaughterhouse personnel
Difficulties in assessing activities carried out on farm
Lack of willingness by local authorities to consider slaughter as an area where animal welfare ‘matters’, as the animals have only a short time to live
The effectiveness of local animal welfare legislation in slaughter plants and on farm may be ineffective as a result of poor enforcement due to:
Limited resources – the slaughter plant may not have the manpower or knowledge to provide adequately skilled and professional personnel to oversee slaughter. Alternatively, the local authority or policing organisation may not have the manpower, time or will to monitor this area of animal use.
Limited training of slaughterhouse personnel – the techniques for best practice of slaughter are widely described and may be laid down in local legislation, but if the staff are not trained in these techniques, they will be unaware of the ways in which they could show improved levels of professional skill.
Difficulties in assessing activities carried out on farm – the problems of achieving best practice methods for subsistence and small community slaughter are outlined in slides 7 and 8.
There may be a lack of willingness by local authorities to consider slaughter as an area where animal welfare ‘matters’ as the animals have only a ‘short time to live’.
There may be variable enforcement, with local or regional differences in accepted practices. This could mean that producers know that it is possible to ‘get away’ with something in one region, but to be prevented in another.
The enforcement body may share interests with those policed, or the industry is policed ‘internally’ – e.g. the body responsible for the protection of welfare at slaughter plants is also responsible for carcass inspection, or management of other parts of the process, and is not impartial in its link with the processor or slaughterhouse.
The local authority may be limited in its powers of access, stop and search, seizure and detention.
The legislation may be poorly designed, and therefore difficult for the courts to interpret if a prosecution is made.

42. Public pressure to improve slaughter conditions
What can the public and non-governmental organisations do to improve slaughter conditions?
They can pressure for a ban or boycott products
They can campaign and lobby to raise public and political awareness of issues
What effect can the public and non-governmental organisations have on improving the conditions of animals at slaughter?
They can, for example, pressure for a ban on some local procedures such as tying up before slaughter, or by supporting a boycott of meat products from countries which do not have legislation to protect animals at the time of slaughter. Such local activity can have a significant impact on producers by raising the profile of issues with consumers who will bring their views to bear via changes in their preferences and spending on animal products.
Animal welfare organisations can campaign and lobby to raise public and political awareness of issues of poor conditions during transport and lairage, poor (or no) stunning techniques, and poor control of killing methods. Consumers in many societies are increasingly informed on welfare issues, including issues such as slaughter methods, and producers will often respond to the impact of the informed public.
Through programmes such as those carried out by PETA in India and WSPA in the Philippines and Taiwan, welfare organisations can teach people, through practical training and education, to carry out humane slaughter techniques, make informed judgements on slaughter issues, and relate their local experience to global ‘standards’, and to their dietary and cultural expectations.
They can also promote the allocation of resources to maintain effective policing of existing legislation, and the creation or refinement of existing legislation.

43. Conclusions
Slaughter has a great impact on the welfare of huge numbers of farmed animals
Methods which were once promoted are being superseded by best practice based on good animal welfare science
Best practice can provide improvements in animal welfare and make the work of slaughtermen safer and more ‘professional’
Best practice during transport and slaughter leads to significant improvements in the quality of meat
Slaughter has a great impact on the welfare of huge numbers of farmed animals.
Methods which were once common are now being superseded by best practice methods which are based on good animal welfare science.
Best practice can provide improvements in animal welfare and make the work of slaughtermen safer and more ‘professional’.
Best practice during transport and slaughter leads to significant improvements in the quality of meat by providing conditions which do not stress the animals to levels where their healthy physiology is damaged.

44. Bibliography
Humane Slaughter – Taking responsibility. Humane Slaughter Association,
– site for training in welfare aspects of slaughter
The Welfare of Animals (Slaughter or Killing) Regulations 1995, UK
WSPA Reports: The Facts About our Food – Animal Transport/Pigs/Chicken
FRASER, A.F. & BROOM, D.M., 1996: Farm Animal Behaviour and Welfare. CABI Publishing
GRANDIN, T., 2000: Livestock Handling and Transport. CABI Publishing