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Mobile slaughter of cattle and pigs

Authors:
JTI-rapport
Lantbruk & Industri
339
Mobile slaughter of cattle
and pigs
Christel Benfalk
Kristina Lindgren
Mats Edström
Qiuqing Geng
Åke Nordberg
© JTI – Institutet för jordbruks- och miljöteknik 2005
Citera oss gärna, men ange källan.
ISSN 1401-4963
JTI-rapport
Lantbruk & Industri
339
Mobile slaughter of cattle and pigs
equipment, docking, animal handling, working
environment and waste handling
Christel Benfalk
Kristina Lindgren
Mats Edström
Qiuqing Geng
Åke Nordberg
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Contents
Summary..................................................................................................................5
Background..............................................................................................................8
The view of the consumer.................................................................................8
Mobile abattoir.........................................................................................................8
Equipment and flow chart .................................................................................8
Location and docking of the mobile abattoir at a farm ...................................10
Development of the docking of the mobile abattoir........................................11
Handling of animals and food hygiene..................................................................11
Animal welfare................................................................................................11
Slaughter .........................................................................................................13
Official inspection...........................................................................................15
Chilling system................................................................................................16
Water ...............................................................................................................17
Origin labelling ...............................................................................................18
Case study – some special considerations concerning pigs...................................18
Stunning methods............................................................................................19
Animal handling, feed and water ....................................................................20
Stunning area...................................................................................................21
Chilling............................................................................................................26
Working Environment ...........................................................................................27
Literature review of work environment in abattoirs........................................28
A field study in stationary abattoirs ................................................................29
Working environment in mobile abattoirs ......................................................31
Waste management................................................................................................33
Legislation.......................................................................................................33
Amounts, composition and classification of waste.........................................34
Collecting and pre-treatment of waste in the mobile unit...............................37
Storage and transport.......................................................................................38
Methods for treatment of slaughter waste.......................................................38
Economy ................................................................................................................40
Stationary slaughter houses.............................................................................40
Mobile slaughter units.....................................................................................40
Case study .......................................................................................................42
References..............................................................................................................42
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Summary
The transport of animals to slaughter is well documented and often the animals
suffer from stress and injury. This can be caused by bad conditions during the
loading, transport and unloading and by aggressiveness between animals. Many
measures are needed to improve the situation. In some cases, mobile slaughter
could be used to reduce the transportation of animals. It is possible that the
consumers’ will view mobile slaughter as a system that promotes animal welfare
therefore meat slaughtered in mobile abattoirs could be more attractive. This
requires that the consumer should be able to inspect the slaughter at any time,
and find that the animals are handled in a good way from the pen in the stable
until they have been stunned and killed.
According to the EU regulation on the hygiene of foodstuffs (EC) No 853/2004,
mobile abattoirs are approved for all kinds of animals. It is crucial that the
requirements of a good hygienic standard and good animal welfare are obtained
when mobile slaughter is practised. Some critical points are summarised below.
Water and chilling
It is recommended to investigate water access and quality well ahead of time,
before the start of a mobile slaughter operation. The water used for slaughter must
be of the same quality, as water intended for human consumption and it should
be analysed regularly. Water of good quality can be transported to the mobile
abattoir in water tanks. The amount of water used depends on the technique and
less water is needed for skinning (~3-5 m³) compared to scalding (~10 m³).
The chilling process should be thoroughly planned and its capacity should be
checked by a practical study before starting the slaughter at full scale. If a hydrau-
lically folding out chill room is used the mobile abattoir cannot be moved until the
chill room has been emptied. Before moving the mobile abattoir, the carcasses can
be transferred to a separate container for continued chilling. The carcasses could
also be placed in a stationary chill room on the farm. A third solution, which sub-
stantially reduces the chilling space that is needed, is to cut warm meat (cattle
meat). This can also contribute to a better working environment since cutting cold
meat is bad for the hands and fingers.
Connection to the stable and stunning
The time to set up the mobile slaughter unit at e.g. a farm is about 1 hour and it
takes about 1.5 hours to clean and pack up before the unit can be moved. It is
very important to construct a good connection between the stable and the mobile
abattoir. A well adapted connection is necessary to achieve a good animal han-
dling and working environment. If the animals are kept outdoors and the climate
is suitable, other solutions may be adequate. It is crucial however to solve the
handling of the animals so that the time (distance) from stunning to sticking and
bleeding is extremely short especially with electrical stunning (17 sec).
Stunning by using gas (CO
2
) has not yet been developed for mobile slaughter.
The recommended stunning method today is captive bolt (cattle) and electrical
stunning (pigs).
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Skinning and parting of carcasses
There is a need for technical development if both cattle and pigs are to be
slaughtered in the same mobile. A method for skinning that is suitable for pigs
is also needed since they have weaker skin. Skinning pigs has several advantages
compared to scalding in a mobile abattoir such as less water consumed, less space
required and faster chilling.
With the new regulation, the post-mortem inspection can be done after splitting
the carcass or after parting it into quarters. When the mobile abattoir is moved
the inner ceiling is so low that full size cattle must be parted into quarters. The
conditions are the same in a container for chilling.
Working environment
There is a high possibility that the working environment could be improved by
developing equipment that is adapted to the restricted space in a mobile abattoir.
Some of the problems with the working environment that are difficult to solve
in large stationary abattoirs could probably be avoided in a mobile system.
The working environment in stationary abattoirs involves several risk factors.
Heavy workload and highly repetitive tasks causes musculoskeletal injuries in the
shoulders, arms, hands and back. There is an increased risk for occupational diseas-
es compared to other work groups because of the occurrences of cuts on the fingers
and hands as well as additional work to cut and pack the meat in cold environments.
No study on the working environment of mobile abattoirs has been carried out yet.
Therefore, a pilot study was conducted to identify positive and negative factors of
the working environment in mobile abattoirs as compared to stationary abattoirs.
The results showed that the working environment in mobile abattoirs was good
as all the furniture and equipment are developed with the latest technologies and
modern materials that allow workers to operate with more ease. The work tasks
in mobile abattoirs probably involve more variation than in stationary abattoirs,
and a large number of repetitive one-handed tasks are reduced, which could imply
positive effects on the workers’ health. In mobile abattoirs the rate of slaughter is
moderate and it is easy to achieve the necessary logistic needed to cut warm meat
(cattle meat). This leads to shorter exposure to the cold environment, which could
result in a reduction of cold injuries. The major negative aspect is the limited area,
which leads to a restricted working space for manual handling, e.g. taking off the
skin and splitting of the carcass. The operator must make sure that the volume of
water does not affect the hygiene of the personnel or the equipment. The stainless
steel sheet, which covers the interior walls, provides good hygienic conditions.
Further research should focus on some key factors for the future development of
mobile abattoirs. Smaller machines for automatic removal of the skin and splitting
of the carcass need to be developed. Support for good hygienic conditions invol-
ving sufficient water is also needed.
Waste management
The waste generated during slaughter is divided into different categories based on
the risk of infection. These categories differ in chemical and physical composition,
which makes it necessary to employ different treatment strategies.
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After the outbreak of BSE the animal by-products presenting a risk for trans-
missible spongiform encephalopathy (TSE) have to be sorted out. This fraction is
classified as specified risk material (SRM) and must be completely disposed of
by incineration. The new EC-Regulation No 1774/2002 regulates the processing
requirements and possible uses of animal by-products. Waste generated during
slaughter of animals should be divided into three categories. Each category in-
cludes a number of different waste fractions generated during slaughter. Category
1 contains specified risk material and Category 3 comprises of those animal by-
products that would be fit for human consumption, but are not (for commercial
reasons) intended for human consumption. Category 2 includes all slaughter
waste, which cannot be allocated to either Category 1 or Category 3.
In this study, the emphasis has been on waste treatment methods that facilitate
energy recovery and/or methods for using the produced residue as fertiliser on
farmland. Focus has been on the anaerobic digestion method, but possibilities
for composting and incineration have also been considered and commented on.
Category 3 material minced to a maximum particle size of 12 mm can be digested
if it has gone through a pasteurisation unit at 70
o
C for a minimum of 60 minutes.
Manure and digestive tract content can be treated in a biogas or composting plant
without pasteurisation as a pre-treatment. It can also be applied directly on arable
land. Screened wastewater from the mobile abattoir can be handled together with
the manure and digestive tract content.
The animal by-products, including blood, represent 70-80 % of the total biogas
potential from waste generated during slaughter of animals. In addition, the
animal by-products contain 60-80% of the nitrogen and phosphors, in all waste
generated during slaughter, which is important to consider from a sustainable
point of view. Anaerobic digestion offers a sustainable treatment method to
facilitate energy recovery in combination with using the residue as a fertiliser
on farmland.
All the animal by-products can be incinerated. This method facilitates energy
recovery but possibilities for nutrient recycling will be limited.
Composting facilitates nutrient recycling but possibilities for energy recovery are
limited. According to EC-regulation 1774/2002, a composting plant has the same
demand on pasteurisation for Category 3 materials as an anaerobic digestion plant.
Economy
Some cost calculations for mobile slaughter at different slaughter capacities
(number of animals per day) from the year 2002 are presented. A case study from
a group of farms producing fattening pigs is reported. A theoretic remodelling
of the slaughter delivery was made. The average delivery per week as well as the
length of slaughter events at the same farms is presented. In 78% of all slaughter
days the mobile could slaughter one whole day or more at the same farm after
remodelling.
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Background
The countries of Scandinavia have been the forerunners in discussing mobile
slaughter. In reindeer production, mobile slaughter has been in practice since 1960
when the Sandstrom Company in Lulea built the first unit. Ever since, the units
have developed in accordance to the regulations and recommendations concerning
hygienic practices from the Swedish authorities. Reindeer used to be the only
animal allowed in mobile slaughter units, but today according to the EU regulation
on the hygiene of foodstuffs (EC) No 853/2004, mobile abattoirs are approved for
all kinds of animals. This report deals with mobile slaughter of cattle and pigs only.
The view of the consumer
High quality meat is of great importance for most consumers, although an increas-
ing interest in animal welfare is also observed (Barton Gade, 1997). Consumers'
perception of good animal welfare is equal to production conditions that “look
good”. For instance, the view of pigs walking by themselves is nicer than shriek-
ing pigs being forced ahead with electric prods. As a result of this perception,
when the handling of animals is to be evaluated, studies of animal behaviour have
to be included (Barton Gade, 1997). To make such a study consequential, the need
for knowledge on ethology, stress theory, animal welfare, meat quality,
microbiology, legislation, ethics etc is crucial (Algers et al., 2000).
At the EU conference, Food Chain 2001, Safe-sustainable-ethical, in Uppsala,
March 2001, the importance of food being produced in unison/harmony with the
consumer’s and society’s standards on food safety and ethics was emphasised in
several sessions. It was declared that methods for measuring animal welfare are
available (Keeling, 2001), that such methods can be used for studies of the impact
of ways of housing and handling animals (Wechsler, 2001) and that good welfare
in many cases are profitable (Oltenacu, 2001).
Investigations of Swedish consumers’ willingness to pay (WTP) for farm animal
welfare has revealed an increased WTP for meat from pigs slaughtered in mobile
abattoirs (Liljestolpe, 2003; Andersson et al., 2004; Carlson et al., 2004).
Mobile abattoir
Equipment and flow chart
The Swedish mobile slaughter units available today, “SANMO Multi-Spieces,”
are designed by the Swedish company Gillteknik in Gallivare and built by
Sandstroms Transport Products in Lulea. The units are mainly used for reindeer
and buffalo. The companies have also designed a unit for pigs for a potential
British customer. The set-up for this pig unit has been approved by MAFF
(Ministry of Agriculture, Fisheries and Food) in London, USDA (United States
Department of Agriculture) in Washington and AAC (Agriculture and Agrifood,
Canada) in Ottawa. In Figure 1, an example of the equipment for mobile slaughter
of pigs is given. If scalding is used there must be a separate trailer with a container
for chilling. The scalding tub is so big that there is no room for the hydraulically
extended chill room, which otherwise can be included in the mobile abattoir.
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Equipment:
trailers where slaughter and chilling is conducted,
trailer or lorry for transport of meat (possible also used for chilling of meat),
container for slaughter waste.
Figure 1. Example of the equipment for mobile slaughter of pigs connected to a stable.
When scalding is used there must always be a separate trailer with a container for
chilling.
1. Inspection (ante mortem) of living animals (within the last 24 hours before slaughter)
2. Raceway up to stunning
3. Stunning
4. Schackling and hoisting
5. Bleeding chamber
6. Skinning or scalding and dehairing
7. Evisceration and splitting
8. Post mortem inspection
9. Classifying and registration
10. Chilling, refrigerated section
11. Chill room for detained meat
12. Waste container
13. Staff premises
14. Separate lorry for transport of mobile abattoir and chill container
The slaughter unit for pigs weighs 22 tonnes and has a length of 13 m in transport,
17.5 m when parked for use. Corresponding figures for the unit for big animals
are 32 tonnes, 15.5 and 19 m (www.atlweb.net). The units are built either on a
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3-4-axis trailer with drawbar or on a 2-axis semi trailer. To tow the trailers, a
heavy lorry is needed. There is also a separate vehicle to transport the container
for chilling the meat. The waste is transported in containers with a vehicle that is
capable of hauling any other regular container transports.
It takes around one hour to park and prepare the unit for operation, packing-up the
unit is somewhat shorter. During slaughter, six personnel are needed for highest
efficiency: two for bringing the animals forward and for stunning, one for bleed-
ing and one for skinning or scalding, one for evisceration and one for weighing
and classifying. In addition, one official veterinarian shall be present throughout
both ante-mortem and post-mortem inspection.
The economic analysis for mobile pig slaughter in this report is based on the plan
for the British unit. The calculations for the slaughter of cattle are based on data
from the units for reindeer and buffalo. Generally, the chilling capacity of the
units set the overall slaughter capacity. In the case of reindeer this is of less im-
portance due to the naturally low temperature in the production area, as compared
to slaughter in most other geographical areas.
Location and docking of the mobile abattoir at a farm
The possibilities for operating a mobile slaughter unit are dependent on the
conditions of specific farmsteads. In a Swedish case study, the conditions for
mobile slaughter on 12 farms with pig production were documented.
At most of these farms it was quite easy to find a way to place the mobile abattoir
in front of the existing loading door. In one case it was very difficult to make
room also for the chill container. For situations like that, the best alternative
would have a mobile unit with a hydraulically extended chill section that is
possible to fold in and out. This requires, in the case of pigs, that the animals
be skinned instead of scalded, since a scalding tank is too large to be combined
with the extending chill section.
It is an advantage if there is access to the back door of the chilling container for
loading of carcasses to a transport vehicle. If not, they can be loaded through the
front door, or the container has to be moved prior to loading. The placing of the
unit also needs to leave enough room for a tractor to empty the waste container.
When unloading the mobile to be standing on legs, an area 20-m long is needed
for the lorry to drive straight forward.
This case study was based on mobile abattoirs being available on the market at the
time of the study, where the chilling unit was on one side and the staff premises
and waste container on the other. These mobile abattoirs have an intake for the
animals on the rear gable, but there is no area to stun the animal. An area for stun-
ning must be created in connection to where the mobile abattoir is attached to the
stable. This is described under "Docking unit with stunning area". Possibilities for
different ways of docking the mobile unit are discussed under "Development of
the docking of the mobile abattoir".
All farms must be equipped with a "unit" where the stable and the mobile abattoir
are docked together. Amongst other things, the size of this unit depends on the de-
sign of the mobile abattoir, already existing loading areas in the stable, the wanted
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time interval between collections of more pigs, feeding routines and number of
staff. Also, the conditions in front of the building may have an impact. The dock-
ing unit should be easy to clean with water and possible to close up with doors.
The transport vehicle places the mobile abattoir approximately 0.5 m from the
stable on its support legs at a level adjusted to the level of the stable floor. The
present versions cannot be lowered below 0.4 m from the ground. The floors at
several of the studied farms were just 0.1 m above the ground. This implies either
a docking unit with a floor higher than the floor of the stable, or an insulated
tightening wall along the bottom of the exit in the stable wall.
It is necessary to make the docking tight to avoid ice formation on the floor during
winter and undesired draft on animals and people. There are air filled bellows
with which it is possible to get a tight docking on all sides between slaughter unit
and building.
Development of the docking of the mobile abattoir
To reduce the need of investments for each farm, the stunning pen should follow
the slaughter unit. The unit could have an extendable part in the rear, which could
also be possible to lower (pers. comm. Sandström, 2003). The feasibility of arran-
ging this is somewhat dependent on what slaughter equipment is used. The pre-
conditions are probably better with skinning than with scalding. The extendable
part could be 3-4 m long and slightly narrower than the rest of the mobile abattoir,
which today is 3.45 m (dependent on what equipment there is) (pers. comm.
Sandström, 2003). Such an overhanging part would eliminate the need for a
stunning pen in connection with the stable. For this arrangement to work, the
inside of the stunning part of the mobile unit must be designed so that the animals
do not hesitate to enter.
At some farms, it will be difficult to completely replace the need for a special
docking construction on the stable. If there is not enough room in front of the
building to let the mobile attach at right angle to the wall, the unit must be placed
further from the stable to make room for the extending parts (chill section and
staff unit) and the waste container.
If the extended stunning section of the mobile slaughter unit could open to the
side instead of in the rear, the necessary stretch of the docking corridor would be
shorter, when placing the mobile abattoir parallel to the building. It is possible to
develop the extendable stunning section so that one can change between opening
in the rear or to the side from farm to farm (pers. comm. Sandström, 2003).
Handling of animals and food hygiene
Animal welfare
According to a draft proposal for the organisation of official controls on products
of animal origin for human consumption the official veterinarian shall supervise
the animal welfare during transport and slaughter. If the rules concerning protec-
tion of animals are not respected, measures such as slowing down or stopping the
process, may be taken by the official veterinarian (EC) No 854/2004.
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The personnel’s skills and experiences
The most important condition for good animal and food handling is interested
personnel with adequate and continuous education as well as personnel, who
possess other skills and are permitted to take their own initiative. Well-educated
persons can and should take on responsibility. Appropriate education and respon-
sibility leads to a higher degree of professional pride. To be the most proficient,
the personnel must have good equipment and work in well-planned systems.
Important experiences from Denmark and Sweden are that several measures
taken to improve animal welfare are also economically profitable.
Another important condition is that the personnel has a given right to express
their opinions concerning work management and the work environment and to
take part in the planning of both. This means that the management person has
to have adequate education in good animal and food handling and for managing
personnel. He or she should also be in close contact with the actual work being
done in the slaughter unit.
Environment and heredity
Animals can be difficult to handle during transport and slaughter dependent
on both their heredity and the environment where they were raised. Results
from research showed that regular good animal handling and access to toys
such as chains or rubber parts to reduce inactivity resulted in pigs that were
easier to handle. Pigs from larger groups were less aggressive and outdoor pigs
were calmer in new environments than intensively reared pigs.
Impact of transport
Just about all animals are transported before slaughter in Europe today. With an
ongoing decrease in the number of abattoirs, the transportation distance in remote
areas increases. An important advantage of mobile abattoirs is that the animals
do not need to be transported. However, there is a limit on how often the mobile
unit can be moved. There may be situations where the following question arises:
should a small group of animals be transported to a nearby farm where the mobile
unit is set up or should the mobile unit be moved?
In reviewing field research on the impact of transports on animals it was revealed
that many studies have been conducted. Nevertheless, only few studies are
comparing animals that are transported prior to slaughter to animals that are not:
Brown et al. (1998) compared the meat quality from two groups of pigs. One
group was exposed to minimum stress and had close contact with their personnel.
The other group was commercially handled. Samples of blood showed differences
in the level of both physical and mental stress. In most of the parameters concern-
ing meat quality the differences were small or none. Fàbrega et al. (2002) com-
pared one slaughter process (transport time, lairage time) that was long (3.25 h
transport and 12 h lairage) and one that was short (30 min transport and 2 h
lairage) by measuring the heart beat frequency, for example. The measurement
showed that loading induced more stress than transport. Wiklund et al. (2001)
had similar results in a study on reindeers, where the level of cortisal increased in
connection to loading and unloading.
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The rate of slaughter
At a big stationary abattoir, a high slaughter rate is economically essential. This
high rate is difficult to pair with good animal treatment. To solve this issue and
to minimise the use of electric prods, systems where pigs are handled and even
stunned in groups have been developed. Danish abattoirs have been leading in
this field as a result of the research at the Danish Meat Research Institute.
With mobile slaughter units, the rate of slaughter is lower and the demands on
quick handling of the animals are not extreme. Individual stunning in a well-
planned system can probably be used without lowering the slaughter rate. It
is always important however to adapt driving and stunning techniques to the
expected slaughter rate. Otherwise, there is an obvious risk for stress leading
to bad working conditions, bad animal handling and damaged meat.
Premises and handling of animals
In designing waiting pens, driving paths and stunning areas, the following criteria
need to be fulfilled in order to reduce stress and facilitate the handling of the
animals:
uniform floor material,
carefully prepared light,
low noise level,
appropriate temperature and ventilation, and no draft,
access to drinking water.
If there are differences in the floor surface, this can be camouflaged with e.g.
sawdust or chopped straw.
Ways to take advantage of an animal’s curiosity is to have closed walls instead
of grills and to let them move towards lighter areas. Cattle e.g. prefer uniform
softened surfaces and tend to walk better on an upwards incline. Animals that are
kept loose in groups should be moved in groups for stunning. One method that
is working very well in weighing situations and in stationary abattoirs is having
cattle move in a curved walk.
Slaughter
There is a lot of research on the physiological impacts of the stunning method.
In contrast, knowledge about how often stunning fails in practice is very limited
(private comm. Algers B., 2001). Research and practical experiences indicate that
an animal is not stressed standing beside another animal being stunned as long as
the first animal is not stressed by other factors (Grandin, 2000). For herd animals,
it is better not to separate the animal from the others in the group before stunning.
However, the sticking and bleeding is often done away from living animals.
Spare equipment must be kept at the place of slaughter for emergency use
93/119/EC.
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Stunning of cattle
For cattle, captive bolt or bullet is suitable for stunning. The pistol shall be placed
at a right angel to the skullbone. Before stunning, cattle are to be restrained in
an appropriate manner to spare them any avoidable pain, suffering, agitation,
injury or contusion. They can be restrained in a restraining box. Since it has to
be very steady, adaptable to different sizes of cattle and have one side, which can
be opened, the restraining box where cattle are to be stunned should preferably
belong to the mobile abattoir. From there, the animals need to be moved quickly
to where they are drained of blood. Draining by cannula and pipe may be pre-
ferred instead of above the grid in the slaughter area. It is important that the
personnel are well protected against kicks from the stunned animal.
Stunning of pigs
For stunning of pigs gas, electricity and captive bolt or bullet can be used. At
stationary abattoirs the method of gas stunning is becoming more common. The
advantages are that pigs can be stunned in groups, no restraints are needed and
the flock behaviour can be utilised. The technique for stunning by gas has not
been adapted for mobile slaughter units. The other methods for stunning and
a suggestion on how to handle pigs during stunning and bleeding in a mobile
abattoir are described in the Case study (page 20).
Bleeding
Before sticking and bleeding, the personnel should make sure the animal is
unconscious. The bleeding should begin immediately after stunning and before
the animal regains consciousness 93/119/EC. This implies that after electrical
stunning the bleeding should begin within 17 seconds (pers. comm., Barton Gade)
and when using captive bolt, bullet or gas within 60 seconds. After bleeding,
the personnel should make sure that the animal is dead before further processing.
Bleeding in a mobile unit
Today bleeding of reindeers is made above a grid. An alternative is to use a
cannula attached to a tube. With this method, separate sterilisation equipment
for the cannula is necessary.
Scalding and skinning
Pigs are traditionally scalded. The hide of cattle is usually pulled off by attaching
ends of the hide to a drum with chains. This method can also be used for reindeer,
sheep and older pigs e.g. sows, which have strong hides. Fattening pigs have
weaker hides, therefore, they can be skinned by drums pulling the hide from each
side of the body, from the belly and towards the back. This method was found
useful for pigs in several studies in Denmark and Sweden. When pigs are skinned
the best hygiene was achieved when using a conveyer to move the carcasses on
the rail rather than manually.
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Scalding and skinning in a mobile unit
Pulling off the hide in a mobile abattoir, from e.g. cattle, differs from the
technique used in stationary abattoirs in that the drum is mounted on the floor
instead of in the ceiling. This means the pulling starts from the hind legs instead
of the front legs. This method cannot be used for fattening pigs since the hide is
too fragile. An alternative, to scald in a tub, which is used in stationary abattoirs
is to scald hanging pigs, however it takes up a lot of room and is too expensive
for use in a mobile abattoir. Scalding in a tub could be a viable alternative.
If the same equipment is to be used for skinning both pigs and cattle, it needs to
be adjustable for different carcass sizes and adaptable to the weaker pig hide. An
alternative technique could be developed, where the carcass is placed in a cradle
on its back. The hide is parted over the belly and fixed to the cradle on the sides
and as the carcass is lifted some manual cutting is being done. This technique
does not work for products that are traditionally sold with the rind left on.
Evisceration
The viscera should be taken out as soon as possible after stunning and bleeding.
The parts of a slaughtered animal (viscera, carcass etc) must remain identifiable
as belonging to a given carcass until post-mortem inspection is completed (EC)
No 853/2004. The carcass of cattle should be marked in a way so that their origin
can be traced until cutting of the meat.
Official inspection
Inspections in question are:
veterinary control of living animals and of meat,
audits of HACCP-based procedures,
general hygiene check of the premises, equipment, personnel and collection of
samples for checking the presence of specific bacteria, diseases, antibiotics etc,
water quality,
waste management.
In abattoirs, at least one official veterinarian shall be present throughout both
ante-mortem and post-mortem inspection. However, an authority may adapt the
veterinarians’ presence in certain abattoirs (EC) No 854/2004.
Post-mortem inspection and detained meat
Before the post-mortem inspection is completed the carcass and viscera must not
come into contact with other carcasses or wall surfaces (EC) No 853/2004. The
new regulation (EC) No 853/2004 allows post-mortem inspection after splitting
the carcass or after parting it into quarters. When the mobile abattoir is moved
the inner ceiling is so low that full sized cattle must be parted into quarters. The
conditions are the same in a chilling container.
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There must be lockable facilities for the refrigerated storage of detained meat
and separate lockable facilities for the storage of meat declared unfit for human
consumption (EC) No 853/2004.
Food business operators shall not place on the market pork or beef unless it has
a health mark (EC) No 853/2004, which the carcasse receives after a successful
post-mortem inspection. This probably implies that, the carcasses must be either
approved by a health mark or discarded before they may leave the mobile abattoir.
Whether the abattoir may be moved, while containing detained carcasses, (e.g.
while awaiting results from laboratory tests), will have to be decided by the local
veterinarian authorities for each abattoir.
Most suitable is probably to place detained carcasses in separate lockable facilities
for chilling and storing detained meat inside the mobile abattoir. If the viscera are
put into plastic bags they can hang with the carcasses in the chill facility but they
should be discarded when the inspection is completed. Meat that has been
declared unfit for human consumption must always be stored in separate lockable
facilities (EC) No 853/2004.
Chilling system
Meat and offals should be chilled immediately after slaughter to no more than
+7 °C for meat and +3 °C for offals (EC) No 853/2004. The chilling process of
a carcass may take several days without causing any negative consequences. In
Sweden, it is common to cool a pig to +7 °C within 24 hours and cattle within
48 hours. Chilling pigs too fast or to slow can lead to different quality problems
depending on the stunning method. The best way to chill pigs depends on the
stunning method and is discussed in the passage on stunning (page 21).
To maintain good hygienic conditions, the carcass should quickly become cool
and dry on the surface. It is extremely important that partly chilled meat is not
allowed to increase its temperature or surface moisture, which can happen due to
lack of chilling capacity when warm carcasses are added. The carcasses must not
hang so that they contact each other or the walls, otherwise the chilling process is
disturbed and the meat quality affected. The food business operator must ensure a
continuous decrease in temperature during chilling of the meat (EC) No 853/2004.
Premises specific to chilling must have equipment to take care of condensation,
which containers for transporting chilled goods usually do not have. The contain-
ers are not built for chilling, but rather to maintain the goods at a low temperature.
Refrigeration in a mobile abattoir
With mobile slaughter, quick chilling is of more interest than in stationary
slaughter. The mobile chill room has limited space and may need to be emptied
during the day. If the carcasses are chilled in a hydraulically folding out chill
section, attached to the mobile abattoir, the chill section must be emptied before
the mobile abattoir can be moved. Before moving the mobile unit the carcasses
can be transported to a separate container for continued chilling. A chilling
container 14 x 3.1 m can hold about 25 cattle (parted in four parts) or 110 pigs
(split in half). It is recommended that the chilling capacity is practically studied
before starting the slaughter at full scale. The carcasses could also be placed in
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a stationary chill room at the farm. The authorities can allow transport of the
carcasses with a temperature above stipulated storage temperature; however,
the transport time must not exceed 2 hours (EC) No 853/2004. The carcasses
should not be transported until the surface of the carcass is dry and cool.
Cutting warm meet (cattle meet) can substantially reduce the chilling space
needed. This can also contribute to a better working environment since cutting
cold meat is bad for the hands and fingers. In this case, the meat must be trans-
ferred to the cutting room either directly from the slaughter area or after a waiting
period in a chilling or refrigerating room (EC) No 853/2004.
Normal transport vehicles for carcasses only have refrigeration units with the
capacity to keep chilled meat cold, not for chilling it. If the mobile unit is used for
slaughter all year around a chilling system with high capacity must be used unless
the climate is cold in summers.
Water
It is recommended to investigate the access of water and its quality well ahead
of time. Water used for consumption, cooking or preparing food is regarded as
drinking water. Consequently, the water used for slaughter must have the same
quality as drinking water and it should be analysed regularly. After December 25
th
2003, applicable regulations for drinking water quality are 98/83 EC, adapted to
the EG-directive 2000/60/EC.
A considerable part of the water used for slaughter is heated, which has some
cleaning effect, but cold water is also used for rinsing, for instance. Furthermore,
heat alone cannot eliminate chemicals. Chlorine can be used for cleaning the
water from bacteria but is not effective on chemical substances.
By completing a thorough investigation of and planning according to the water
supply from the beginning, one minimises the risk of setbacks during slaughter
later on. High quality water can be transported to the mobile abattoir in water
tanks. The amount of water used depends on the technique and less water is
needed for skinning (~4-7 m³) compared to scalding (~8-10m³).
Responsibility of producer, flow and quality
If water is to be taken from an internal well on a farm, the quality must be
checked and approved in advance. The supplier, in this case the farmer, is
responsible for the quality. Sampling for microbiological and chemical analysis
(audit monitoring) needs to be done. It is also advisable to let a geological expert
consider the position and construction of the well. The pressure and flow capacity
at the tap point must be sufficient. Deep bore wells will work in many cases,
while dug wells are more questionable to use. After the analysis, the water supply
should be discussed with the local veterinarian authority.
Commercial use of water implies routines for cleaning of reservoirs. A reservoir
in this case can be a pressure tank or something similar. There shall also be a
description of the water distribution system and a specified person responsible
for the operation of the system.
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Quality requirements and frequency of sampling
If the enterprise wants to haul water from private wells, the water must be
analysed in advance as mentioned above and regularly thereafter (check
monitoring). This is to guarantee that the water quality has not deteriorated
by poor hygienical conditions in the well, reservoirs or pipes. Water used for
slaughter shall fulfil the requirements for drinking water, 98/83 EC. Before the
water is used, an audit monitoring must be completed. The purpose of audit
monitoring is to provide the information necessary to determine whether all of
the Directive's parametric values, of microorganisms and chemical substances,
are complied with. All parameters must be subject to audit monitoring unless
it can be established by competent authorities that a parameter is not likely to
be present. Parameters for radioactivity have special monitoring requirements.
The purpose of check monitoring is to regularly provide information on the
organoleptic and microbiological quality of the water. This is done by analysing
some chosen parameters stated in the Directive. Member States may add other
parameters if they deem it appropriate. The sampling requirements can for
instance be included in a HACCP-based procedure for the mobile abattoir. The
Member State authority may decide about the frequency of sampling when the
water distribution is less than 100 m³ per day.
Rate of use and the addition of chlorine
Whenever there is a break in the use of the slaughter unit for vacation or for
another reason, it is advisable to chlorinate the water to avoid microbiological
growth in tanks and pipes. The old chlorinated water must then be replaced
with new fresh water before the mobile abattoir is operating again.
Origin labelling
One of the interesting advantages with mobile slaughter units is the possibility
to easily label and handle small quantities of meat separately. The meat can be
delivered fresh to the local market.
Case study – some special considerations
concerning pigs
In meat especially pork, a too large decrease in the pH-value during the slaughter
process caused by stress will result in PSE meat (Pale, Soft and Exudative). In
Sweden, the breeding programs have successfully reduced the risk of death and
PSE due to stress before slaughter. However, the risk of PSE meat due to a pH
drop in the muscles after slaughter still exists. Also, the kicks and cramps caused
by electric stunning can contribute to the occurrence of PSE.
The object of this case study (Benfalk et al., 2003) has been to suggest a method
to slaughter pigs in a mobile abattoir that is based on comprehensive and proper
animal handling practices. The choice of method for stunning the animals, as well
as the demand for high meat quality, has impact on how the premises of where the
animals are handled should be designed. This chapter begins with an exposition of
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factors, especially choice of stunning method and its affect on meat quality. There-
after suggestions on how to design waiting areas (lairage), stunning areas and how
to dock the mobile abattoir are made. There is also a presentation on the labour
requirements for handling the animals from their pen in the stable to stunning.
Stunning methods
The recommended method to use on pigs in mobile abattoirs is stunning with
electricity. Combining electrical stunning with cardiac arrest (heart stop) with
electricity is another method discussed for pigs. Stunning with bolt or bullet is less
suitable and as mentioned before gas stunning has not been developed for mobile
slaughter.
Stunning with electricity
In smaller abattoirs, electric stunning is often practiced. The animals need to be
used to being handled by people. Heavy strains on the animals, such as internal
bleeding and broken shoulder-bone, often lead to deterioration in the meat quality.
Electrical stunning leads to more bleeding than does the use of CO
2
. During elect-
rical stunning the blood pressure increase is higher and this, in combination with
the heavy contraction of the muscles, is probably the reason for more frequent
bleeding in the meat. Fractures, sometimes completely without bleeding, occur
only with electricity. By holding the tongs around the pig's head to make it fall
slower the risk of fractures is lowered. Bleeding should start within 17 seconds.
A Danish study concludes that electric stunning gave more tender meat, but also
more PSE meat, than did stunning with gas. To limit the reduction of the pH-value
after electric stunning and the occurrence of PSE induced thereafter, especially in
the deepest part of the ham, it is important to effectively chill the meat. To reduce
the frequency of PSE, there is also a need to reduce muscle cramps after stunning.
By reducing the cramps, the bleeding will also be less frequent (Økologisk
jordbrug, 2002).
Electrical stunning and cardiac arrest
With electrocution, the animal cannot wake up before bleeding and the contrac-
tions after stunning are reduced. The animal is put to death directly after (2 sec)
it has been stunned by electricity, by putting the electrodes against the heart,
which will then stop. Before cardiac arrest the animal must be stunned, otherwise
the animal will suffer from severe pain. A well performed stunning should affect
the brain and knock out the consciousness without any pain or discomfort for the
animal.
After stunning, if the pigs are killed by electrocution there would be less time
stress between stunning and bleeding. The stop of the heart does not reduce the
amount of blood released from the animal (Warriss & Wotton, 1981). Still, it
is advisable not to wait more than two minutes after death before starting the
drainage. If so, some blood will stay in the big veins, liver and guts. However,
there will not be more blood in the meat due to postponed drainage.
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Equipment for electrical stunning and stopping the heart
Common equipment for electric stunning is the size of a shoebox and connects to
an ordinary single-phase socket. From the transformer there are 3-4 m long spiral
cords attached to the tongs. The transformer box is prepared for wet environ-
ments. German equipment has been developed to combine stunning and heart
stop, which includes transformer, control unit and tongs. The amperage and
voltage need to be lower for the heart (1.3 A, 50 Hz, 300 V) than for the head
(1.5 A, 50 Hz, 380 V).
Stunning with bolt or bullet
Stunning with bolt or bullet is not as suitable for pigs as for cattle. One reason is
that it can be difficult to approach a pig from the front and to touch its head. Also,
the animals vigorous kicking that follows the stunning with bolt or bullet can
easily result in poor quality pork.
Animal handling, feed and water
The areas where the animals are moved should be designed in a way to make
the animals move in the right direction by themselves. The environment should
resemble as closely as possible the environment in the stable, until the animals
are stunned. Big differences in floor levels must be avoided. It must be possible
to bleed the animals immediately after stunning (within 17 sec after electrical
stunning). The handling of the animals must always be such that it can be shown
to any consumer.
Feeding the pigs
Pigs should not be fed the morning before slaughter. This makes them easier to
move and less sensitive to stress. There are also advantages in less manure and
less content in the intestines. When mobile slaughter is practised it is important
to have a strategy for how to feed and water all the animals in the stable. In pig
production there is usually a variation in body weight between animals in the
same pen. The first pigs to be slaughtered are together with those who will be
slaughtered at a later date. Mobile slaughter will also have an impact on the feed-
ing of pigs that will not be slaughtered. It is very stressful for pigs to experience
other pigs being fed, but not them. Hence, the remaining pigs, in the same section,
should not be fed until all the pigs that will be slaughtered are removed. Instead,
all the pigs can be fed during the night before slaughter. This can replace the
morning ration. At the next feeding time, all pigs in the section could be given
some straw and fluid feed (diluted).
In many stables the gates to the dung area will be shut as pigs are hauled for
slaughter. This will lead to some littering in the pens. However, the amount
of manure will be less than a usual day due to the different feeding times.
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Water
When the pigs are in a waiting pen (lairage) they must have access to water
(93/119/EC). If they are taken directly to stunning and slaughter, water can be
omitted in the slaughter area. However, it is important that the rest of the pigs in
the stable can access a water point at all the time. They must also be able to drink
when the gates to the dung area are closed. Some farmers reported that they can
solve this by distributing wet feed with very low dry matter content.
Prevention of stress and tail biting
In some big stables, there could be hauling of pigs going on for five hours or
more. One farmer pointed out the risk of stress when there is activity in the stable
all day long. Another farmer noted that his pigs were not bothered at all if he was
busy repairing something in the stable for a day. Most likely, there are differences
between herds in this matter, depending on e.g. automatic or manual feeding.
When there are pigs left for slaughter at a later event or even the next day, one
needs to pay attention so that tail biting does not occur. To prevent this, extra
straw or something of a similar nature can be given. Also, during lunch break the
gates to the dung area (if pigs are moved from the pen through the dung area)
should be opened and the light adjusted.
The pain and stress associated with identity branding can be avoided with mobile
slaughter. The pigs do not have to be marked with their identity since they do not
leave the farm alive. It is sufficient to mark the slaughtered pig.
Stunning area
When relocating pigs, the animals should move themselves because of their
curiosity. The need for driving them should be minimal. It is important that the
more cautious individuals don’t loose contact with the “leaders” bringing the
group forward. Labyrinth design tends to slow down the leader and keep the
group together. Narrow paths (one-line traffic) leading to stunning are proved
to have high stress impact on the animals. It is better to move and stun pigs when
they are in a group.
Pigs tend to walk towards lighter areas, if not blinded. Lamps should preferably
light up the floor without creating shadows. The climate in the premises needs
to be adapted to what the animals prefer. This means appropriate ventilation, and
in Sweden also isolation from cold. Draft should be avoided. When designing
driving paths, stunning area and pens for waiting, the following criteria must be
fulfilled in order to reduce stress and facilitate the handling of the animals:
uniform floor material,
carefully prepared lightning,
low noise level,
sufficient ventilation and no draft,
access to drinking water.
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Pigs walk upwards, but the slope in a raceway should not exceed 17 %. The floor
of the stunning area should be plain and in the same material, or at least similar,
to the rest of the stables. The most common floor is concrete. All farms in the
case study had concrete. To make it easier to move the animals, changes to the
floor material need to be avoided. Changes make the animals hesitate. They might
register the change as a hole or barrier, which scares them. If there is a change,
it could be camouflaged by straw or another bedding material.
Pigs like to walk towards lighter areas, as long as they are not blinded. This is
easy to arrange with a well-lighted stunning area. It is important that the floor is
lighted without any shadows.
It is also important that the noise level in the stunning area is low, in spite the
fact that it is close to the slaughter activity. Sounds from the slaughter unit can
be diminished by transparent plastic strips, 5 mm thick. These strips are easy to
rinse with water, and to pass by.
The climate in the waiting pen and the stunning area shall be adjusted to the
thermal comfort preferred by the animals. This means the premise needs to be
isolated and have sufficient ventilation. The ventilation should be designed such
that the animals do not need to walk against the airflow when approaching the
stunning area.
Docking unit
The suggestions on how to attach the mobile abattoir to stables presented below
are based on the design of the mobile units in use today. All these units have
animal entry placed in the rear. Stunning with electricity is assumed to be con-
ducted in the docking unit of the stable, while bleeding is done inside the mobile
unit. To minimise the time between stunning and bleeding the tongs can be kept
around the pigs head until it has been shackled and hoisted. In the examples
below, a minimum of one waiting pen and one stunning pen is installed at each
farm.
The alternative described above in "Location and docking of the mobile abattoir
at a farm" implies a floor in the docking unit on the same level as the floor of the
mobile. If there is a downward facing slope in the building, the rear of the mobile
unit will have to be lifted. Special consideration must then be put into how to
construct an opening that will be possible to dock and be tight.
To be independent from the slope of the ground, a technique for lifting the pig
into the mobile abattoir after stunning but before bleeding is needed. This could
for instance, be a lifting device combined with an inclined plain or a lifting table.
It is important, that this technique is sufficiently examined to ensure a good
working environment in spite of the difference in floor level.
In Figure 2, one suggestion on how to design the docking unit between the stable
and the mobile abattoir is provided. By demoting gates in the lower corner, the
stunning pen can also be used for sows.
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Figure 2. Docking unit with waiting pen and pen for stunning designed for pigs.
Explanation to Figure 2:
The animals are moved from the stable (1) to the waiting pen (3), then to the pen
for stunning (4) and to the stunning area (6). The personnel executing the stunning
are in the pen (5). There is a path for personnel to enter and exit the mobile
abattoir (2). (7) is a path and reserve area.
The animal's body is lifted by a hoist from the stunning pen (6) with the electric
tongs still on its head. The body is then transported on a rail (8) to the bleeding
area (9) and onto the scalding tub.
Several gates are used. Some of them are opened sideways to let the pigs through
while others can be used for moving the pigs forward. Arrows and dotted lines
indicate the functions of the gates.
The objective of the corner of the stunning pen (6) is to make the stunning safer
without separating the animal from the rest of the group. The pen walls should be
made so that the pig can easily see other pigs in the waiting pen.
The idea behind the reserve area (7) is to be able to open up and let the animals
walk through, in case more than one pig enters the pen and the animals refuse to
walk backwards.
The following provides an alternative method for lifting the animal at area (8).
For staff to avoid bending down to hook the animal body there could be a shutter
in the wall of the stunning pen. On the other side of the shutter, approximately
15 cm below the floor in the pen, there would be a tray. Immediately after the
animal is stunned the shutter will open so the animal falls on a tray, which is then
lifted mechanically to a convenient height for the personnel. With this alternative
electrocution (cardiac arrest) will probably be needed after the electrical stunning
to avoid any risk of the pig regaining consciousness before bleeding.
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Waiting area (lairage), alternative 1
One alternative is to have a rather small waiting area, at the docking unit, with 1-3
pens (Figure 2), holding 6-18 animals. With a slaughter rate of ~30 pigs per hour
the animals will be slaughtered within approximately half an hour. One person
needs to be available for moving animals from the pen in the stable to the waiting
area. The advantages of this alternative are: the animals only need to be in the
waiting area for a short period, the costs for the building extension (docking unit)
is minimised and the person doing the stunning receives some assistance. It is
probably most efficient that personnel from the slaughter team handle the pigs
from pen to slaughter. This means more work for the team and that the farmer will
not have to sort out and fetch pigs.
Following safety procedures to prevent transmission of infection i.e. showering
and changing clothes and footwear between farms is especially important in this
alternative.
Waiting area (lairage), alternative 2
Another alternative is to build a waiting area to keep pigs for half a day’s
slaughter; approximately 70 pigs (figure 3). The floor area of the pens in Figure 3
corresponds to a situation where 50 % of the pigs have a living weight below
120 kg (i.e. 91 kg slaughtered weight). Should all of the pigs weigh less than
120 kg, the area could be diminished by 30 %. In alternative 2, the farmer and
a helper sort out and move the animals to the waiting area. The slaughter staff
move the animals from the waiting pens to the stunning area.
Figure 3. A building extension holding 12 pens for six pigs each. The pens can be parted
into two. Docking unit with stunning area.
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A big waiting area lets the farmer concentrate on other tasks between the morning
and lunch. However, this second alternative is not preferable when slaughtering
only a few pigs from each group/pen. Pigs from different pens should not be
mixed together until a few minutes before slaughter. If they have to wait together,
unfamiliar individuals will start to fight with each other, which will lead to stress
and possibly injuries. Ideally, these pigs should wait one by one. This, however,
makes it more difficult to concentrate on the fetching.
With a big waiting area that has several pens, the slaughter personnel do not need
to sort animals. Still, one should calculate for two persons to fetch pigs from the
waiting pens and to stun and bleed the animals, at a slaughter rate of 30 animals
per hour. Although the amount of work is less than alternative 1, it is too much
for only one person. In some stables the fattening pens are close to the exit, which
explains why the difference between fetching the animals in their fattening pen or
a waiting pen is small.
Waiting area (lairage), alternative 3 – a mobile unit
A couple of farmers have suggested a mobile unit that holds waiting pens could
follow the slaughter team. If such a unit could fit into a lorry platform of
9 x 2.4 m, it would hold 35 animals, with no personnel aisle. The unit would need
to have gates, insulation, ventilation and a water distribution system. The main
advantage would be to divide the cost of waiting pens on all producers. The dis-
advantages are that the unit would only keep pigs for one hour of slaughter and
that the unit needs to be transported and docked from the slaughter container to a
stable. It will take up more space on a most likely already full farm yard. Slopes
and other level differences may make this alternative very complicated on some
farms.
Labour requirements with waiting (lairage) areas of different sizes
Labour requirements for animal handling
The time needed, to fetch pigs for slaughter, depends mainly on how the pigs
have been handled during raising, the skill of the personnel and the design of
the driving aisles and waiting pens. Based on information and time studies at
the farms in the case study and a farm with a connected slaughterhouse, the
time needed for fetching 120 pigs was calculated, if waiting pens according to
alternative 1 or 2 (above) would be used.
Assumptions: Ten fattening pigs per pen. At the first slaughter occasion one pig
is picked from each pen. Second slaughter occasion three pigs are fetched per pen.
And at the final slaughter occasion the remaining six pigs per pen are slaughtered
and all the pens are emptied. The average time to move 120 pigs from the pen to
the waiting pen was calculated:
In alternative 1, with only one to three waiting pens, the time calculated to move
the 120 pigs to the waiting pens was two hours, with only one person. Moving the
animals onto stunning, a task integrated with the stunning, was assumed to take
an additional half hour.
In alternative 2, with a large waiting area, the time calculated for two persons to
move 120 pigs to the waiting pens was about one hour. On top of this comes the
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labour requirement for moving the animals from the waiting pen to stunning,
which was assumed to take ~ one hour.
The calculations indicate that labour requirements might be higher with the big
waiting area, alternative 2, since the animals need to be picked up twice and the
distance from waiting pen to stunning is longer.
With alternative 1 it is likely that slaughter staff will be engaged in moving pigs
to the waiting pens and further to the stunning pen as this work is going on all
day. If there is time left, this person will assist in stunning and bleeding when not
fetching pigs.
An economic analysis was made for two levels of production: ~2000 and ~4000
fattening pigs per year (Benfalk et al., 2003). The results indicate that at both
production levels, the cost of using slaughter staff for fetching pigs from the
stable (alternative 1) was substantially lower than building the large extension
(alternative 2) for waiting pens.
Chilling
The possibility to chill pigs in a mobile container was theoretically investigated
using the following data:
pig carcasses were chilled to +7 °C within 16 hours under Swedish conditions;
slaughtered weight, 88 kg (fattening pigs), the carcass is scalded, skull is taken
off;
slaughter rate 30 pigs per hour. U-value of walls, ceiling and floor a maximum
0.4 W²/m² °C, room temperature in chilling container 0-2 °C;
carcasses are hanging on a hook from a rail 2.15 m above the floor (sows are
parted) and distance between the rails was assumed to be 55 cm and the
distance between the hooks 25 cm. Each hook must have a stop because it is
difficult to place the container completely horizontal.
If the pigs are scalded it is not possible to have a hydraulically extending chill
section because the scalding tank takes up too much space.
The electrical effect needed for chilling was calculated in two examples with fully
insulated containers and the refrigeration unit placed inside the container:
1. Container: 7.25m x 2.45m x 2.9m (height) inside, 4 rails: 38 pigs – 28 kW
2. Container: 13.6m x 2.95m x 2.9m (height) inside, 5 rails: 111 pigs – 56 kW
It is important to ensure the cold air is evenly spread. One technique that has
already been used in some abattoirs is to hang textile channels below the ceiling.
The channels have plastic cones to spread the air. Another technique that is inter-
esting is one that is used for freezing bread (“Polarbröd”). In order to have control
of the cold air a double ceiling is used and the air is sucked through the products
(pers. comm. Larsson).
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Provided the chilling effect has been correctly dimensioned, it will be the
slaughter rate and the warm air coming through the door that will have most
impact on the chilling process. To minimise the warm air coming through the
door, the temperature could be lowered in the sealed link between the abattoir
and the chill container.
When the carcasses are being chilled a lot of condensation is formed. The
slaughter of 125 pigs gives about 200 litres of condensed water that must be
removed from the chilling container.
Carcasses must not come in contact with other carcasses or the walls until the
post-mortem inspection is completed (EC) No 853/2004. When handling detained
carcasses it will probably be most suitable to place them in separate lockable
facilities for chilling and storing detained meat inside the mobile abattoir. If the
viscera are put into plastic bags they can hang with the carcasses in the chill
facility but they should be discarded when the inspection is completed. When
meat has been declared unfit for human consumption it must always be stored
in separate lockable facilities (EC) No 853/2004. An approval from the local
veterinarian authorities will be needed, if the abattoir is to be moved, while
containing detained carcasses.
Working Environment
Working environment consists of all factors that can affect the working situation.
It concerns the technique design, work organisation/activity, the design of physi-
cal working stations such as local, machines and other technical devices, use of
chemical material as well as hygienic work conditions. It also deals with the
personnel’s psychosocial conditions, for instance, variation of tasks, social contact
and the co-operation and influence in work situation as well. Social contribution
to this aspect is aimed at prevention of illness, accidents and improvement of the
work environment. This is ensued with help of legislation and investment by
authority for oversight and research. However, there has been no specific labour
legislation related to abattoirs. Experience shows that frequent care of the sur-
roundings is positive for the work environment, but there is no absolute coupling
between smaller environmental load and work environment. In addition, applica-
tion of new technology sometimes causes some problems in working conditions,
which requires studies on working environment.
A pilot study of working environment in stationary compared to mobile abattoirs
was conducted. Working conditions in stationery abattoirs were investigated by
a literature review and an in-situ survey for a stationery abattoir for cattle and
pigs. Some workers were interviewed with a questionnaire during the survey. The
working conditions in a mobile abattoir were investigated by a video recording
showing the whole procedure of slaughtering cattle. Positive and negative factors
in the working environment in mobile abattoirs as compared to stationary abattoirs
were identified and discussed.
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Literature review of work environment in abattoirs
The literature review has shown that workers in the abattoir are exposed to high-
force, high-velocity and repeated manual work tasks. Research on the improve-
ments of the working environment in the abattoirs has been studied for many
years. The environment has been improved with newly developed technologies
and occupational training for the workers over the last 5-10 years. Frequent labour
turnover due to musculo-skeletal injuries in spines, shoulders, arms and cuts to
hands/fingers have been reduced after improving the working environment and
occupational training. (Veibäck, 1991; Jönsson, 1992; Sonesson, 1994; Olausson,
1995; Wenander, 1995)
Some studies have shown that an elevated risk for rotator cuff tendonitis occurred
when workers were operating at or above shoulder level. Even with shoulder
elevation above 30 degrees, muscle blood flow in the supraspinatus could be
reduced (Hagberg et al., 1987; Järvholm m.fl. 1988). Anderson et al., (1995)
found that repetitive work at shoulder level with upper arm abduction or flexion
above 30 degrees was associated with risk for subacromial pain. Exposure dura-
tion and age were both important factors. Based on this knowledge, it could be
proposed that reduction of daily exposure time is the most effective preventive
action among workers performing high-speed monotonous work with the upper
arm elevated. In order to reduce the risk of shoulder pain, the workstation should
be adjusted so that the upper arm is lifted as seldom as possible.
Many tasks involving heavy lifting were eliminated through the improvement of
the working environment in a Swedish abattoir. For instance:
installation of hanging evisceration of large slaughter cattle,
replacement of manual skin removal and splitting of the carcass by automatic
machines,
rebuilding of the cutting line workstation with an elevator, etc.
After the introduction of the new production system, the personnel are able to
rotate work stations more often. Work-related diseases were reduced, resulting
in a decreased in sick leave from 60 days/employee in 1991 to 23 days/employee
in 1993 (Sonesson, 1994).
One abattoir reported that there were some problems related to the working
environment, such as lifting heavy things, a one-sided workload and work under
cold condition, etc (Johansson, 1995). In a project on the working place program,
staff was allowed to individually adjust their own working place. The cold outdoor
work was replaced by indoor work as much as possible. Also, work organisation
was changed through communication of responsibility for competence in the
project. It was shown that the employees were more motivated and satisfied with
their work due to the improvement in the work environment.
However, abattoir workers are still one of the groups with the highest incidence of
occupational disease according to statistics from the Swedish Work Environment
Authority and Statistic Office (Arbetsmiljöverket, 2001).
A heavy workload and highly repetitive tasks readily causes musculoskeletal
injuries in the shoulders, arms and hands (Hägg, 2001). Occurrences of cuts and
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thrust injuries to the fingers and hands as well as cutting-up and packing meat in
cold environments (additional cold exposure) cause a higher risk for occupational
diseases than among other work groups (Rintamäki, et al, 2000).
High-force and high-velocity tasks as well as insufficient protection could be
major reasons for the occupational injuries. It is important that the personnel
use protective equipment to diminish the risks of occupational injuries, such as
protective clothing against cold or cutting injuries. It is required that cut protec-
tion equipment must be applied when cutting meat (Olsson, 1998).
A field study in stationary abattoirs
A survey of working conditions in a stationary abattoir for cattle and swine in
Sweden was carried out. Some workers were interviewed with a questionnaire
during the survey. The purpose of this field study was to describe what kind of
work tasks could cause problems with respect to working environment.
Slaughter of cattle
There were four male butchers aged 25 to 53 years. One of them takes care of live
animals at barn and the others are responsible for the slaughtering. They did work
rotations every week. About 200 cattle were slaughtered during 8 hours per day.
When bleeding the cattle, the operator has to bend at an angle of about 90 degrees
to the floor level and manually stick the animal hard with a knife. The worker has
to do this high-force task repeatedly in the awkward posture about 67 times per day.
They often felt pain from the ergonomic load in the shoulders, arm and hands.
In the slaughter line, all the operators stand and twist their posture to manually cut
out the viscera from the slaughtered animal. A repetitive operation is therefore
present in the slaughter line. It was also shown that the cutting line has the same
working posture as that used when cutting meat. Time pressure on the operators
also exists, particularly in the case of increased product demand.
Slaughter of pigs
Five persons worked on killing about 1400 swine per day. One worker had to
slaughter about 300 pigs per day. In the slaughter line, workers start with washing
and scalding of the slaughtered swine bodies in hot water, then automatic scraping
away of hair, brushing, and splitting in machines, and then cutting off the feet on
a desk and hanging them up etc.
Although the process of slaughtering pigs is different from slaughtering cattle,
cutting off the feet and removing the inside organs from the slaughtered pigs
are manual, repetitive and monotonous tasks, which are similar to workloads
in slaughtering of cattle. There were 28 employees (five of them were female
workers), but there was often only 20 persons working at the slaughter line. They
slaughtered 180 pigs per hour, thus they had to perform the manual tasks quickly.
They changed tasks about 5 times per day, as well as the working duration with
the same working postures every 60-90 minutes. This work rotation could be a
way to reduce risk for musculoskeletal injuries.
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It was assessed that cutting injuries occurred 2-3 times per month. The main
reason for the injuries was that the workers did not wear protective gloves due to
uncomfortable feeling of the gloves. The injuries also took place on the lower arm
because the gloves used didn’t protect to the arm (insufficient protective clothing
from the organisation). These cut injuries resulted in the injured worker either
going on sick leave for 2-5 days or being reassigned to other temporary tasks.
Cutting meat in cold
The environmental temperature and the surface temperature of the products are
<7 °C at the meat cutting and packing workshop. Hands with or without gloves
are in contact with cold surfaces during working. In the workshop at the stationary
abattoir 15% of the personnel were reported as being on sick leave. Workers
ignore the protection against cold from time to time, which caused cold pain and
numbness of fingers. Therefore, a risk of hand cumulative cold injury may occur,
especially by touching wet, cold meat. Manual tasks like slicing and packing are
repetitive. Highly repetitive tasks will lead to monotonous responses from the
workers. The repetitive tasks on the assembly lines result in low autonomy and
low job control, which negatively influence the motivation of the workers.
Other environmental factors
In addition, the following physical factors that have essential effects on the
working environment were observed.
Noise
High level noise in the slaughter workshop is generated from working machines,
electric hand tools and cutting lines. Noise is a stress factor that can cause psycho-
logical disturbances and start somatic reactions. Long exposure to noise can lead
to high blood pressure (Jönsson, 1991). Operators must use hearing protection
while working. However, the use of hearing protection leads to a difficult
communication among the workers. Further improvements on this aspect should
be considered, for instance, through encapsulation of the machines or the hearing
protection with earphone that can receive radio programmes or music, etc.
Ventilation
There was an unpleasant smell in the slaughter workshop due to slanted animal
products and poor indoor air ventilation. Improvements to the mechanical
ventilation system in the workplace should be considered so that the air can be
ventilated expeditiously at the times when annoying smells are being produced.
Technique depends on the construct design of the locale. Generally speaking,
indoor air quality should be satisfactory to the workers.
Wet floors
The floor in most of the workplace is wet with blood. This leads to a higher risk
for slips or falls. Prevention of slips and falls should be achieved. For instance, the
floor surfaces should be an open grid made of metal or hard rubber. In this way,
the dropping of blood, water, etc can fall through the open grid onto the floor.
The grid will easily keep the walking surfaces clean and dry, resulting in less falls.
Wearing of anti-slip footwear to protect against slipping is also recommended.
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Working environment in mobile abattoirs
Mobile abattoirs have previously been permitted for slaughtering of reindeer in
Sweden. To our knowledge, not one study on the working environment of mobile
abattoirs has been carried out yet.
In operation, with a well-trained staff of eight people, the abattoir has a capacity
to process 40 large cattle or buffalo per 8-hour shift. The mobile abattoir with a
bleeding section, chill section and personnel room is manufactured from aluminium
strengthened insulated sandwich panels with an external white fibreglass weave
and stainless steel sheeting with fully welded joints internally. The floor consists
of a fully welded, patterned aluminium sheet. The floor slopes towards the middle
where there is a sunken stainless drainage channel with hatches that may be raised
up for cleaning. Internal lighting consists of covered neon-strips/fittings mounted
under the roof. Furthermore, the following equipment mounted in the slaughter
and evisceration section has been designed with ergonomic considerations:
one electrical slaughter bench with various speeds for the removal of hides
with automatic hide discharge through a hatch in the floor,
stainless steel electric elevator for hide removal and transport of the carcass
onto the hang rail,
three height adjustable platforms at workstations,
two air driven flaying knives,
a splitting saw with dedicated sterilization, and has a breastbone divider.
Ergonomic Load
It is clear that stresses and risks of occupational injuries caused by the transport
of living animals will be avoided in the mobile slaughter system and there will
be no lairage work. The work tasks in mobile abattoirs probably involve more
variation than in stationary abattoirs, and a large amount of repetitive, one-handed
tasks are reduced, which could imply positive effects on workers’ health. Another
positive effect of working in the mobile abattoirs is limited exposure to the cold
environment, which could lead to a decrease in the amount of cold injuries. The
major negative aspect is the limited space, causing a restricted working area for
manual handling, e.g., taking off the skin and splitting of the carcass. Also, the
limited volume of water might affect personnel and offal treatment.
Proposal for development of work environment in the mobile abattoir
The results indicate that the work environment in mobile abattoirs is superior as
all the furniture and equipment are developed with the latest technology and
modern materials. Ergonomic intervention for the design of the furniture and
equipment has also been used. A comparison of positive and negative aspects in
the stationary and mobile abattoir together with possible actions for the mobile
abattoir is outlined in Table 1.
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Table 1. Comparison of positive (P) and negative (N) aspects in stationary and mobile
slaughter systems as well as possible actions for the mobile system.
Stationary slaughter Mobile slaughter Possible actions in the
mobile slaughter system
N: transport of animals
causes extreme stress and
risk for occupational injury
P: non-transport of animals,
stress and risk for
occupational injury can be
avoided
N: need of lairage work in the
slaughterhouse stables
P: work with lairage is spared
N: bent and twisted postures
for heavy, repetitive manual
work during bleeding
P: more variation can result in
less heavy, repetitive manual
tasks for workers
P: hide discharge and
splitting of the carcass by fully
automated machine
N: limited space for installing
a fully automated machine
Smaller machines with the
same function could be
developed
N: standing still and one-
sided repetitive tasks at meat
dissecting and separating
band
P: standing still and one-
sided repetitive tasks are
reduced by increased task
variation
N: cold stress during meat
slicing, casing and packing
assembly line in cold room
P: exposure duration to the
cold environment is shorter
Sufficient protective
clothing, especially gloves
against cuts, the cold and
the wet have to be worn
N: loud noise, poor indoor air
ventilation, unpleasant smell
and wet slipping floors
P: installation of ergonomic
instruments and equipment
with new technologies can
easily be done from the
beginning
P: sufficient supply of cold
/warm water for hygiene
N: limited supply of cold
/warm water
Can refill water from the
farm where slaughtering is
performed or install larger
tank
P: large space for manual
handling tasks and a big room
for workers to change clothes
N: limited space A tent as work place or
change room for workers
could be built at the farm
temporarily
P: sufficient room for handling
of waste
N: finite room Manage waste locally
N: long distance for
distribution of meat products
P: distribution of fresh meat
products to local retail store
The mobile abattoir enables workers to operate more safely and conveniently
since the furniture and equipment in the mobile abattoirs are developed with the
latest technology and modern materials.
It is very important to provide good and convenient working conditions for safe
and efficient work, if the mobile abattoir is to be introduced as an effective
alternative. Therefore, further studies of some major factors on the development
of mobile abattoirs could be performed. Smaller machines for automatic removing
of the skin and splitting of the carcass need to be developed. Development of
good hygienic practices, while using limited amounts of water, is also needed.
The recently developed mobile abattoir brings new requirements and standards
to the working environment, which will need further investigations.
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Waste management
The waste generated during slaughter is divided into different categories based on
its infectious risk. These categories differ in chemical and physical composition,
which makes it necessary to employ different treatment strategies. Animal by-
products generated during slaughter are energy-rich and have a high content of
nitrogen and phosphorous. Thus, from a sustainable point of view it is important
to find management strategies for extracting renewable energy and recycling
nutrients back to agriculture.
Legislation
Definitions of waste categories
Waste with animal origin is grouped into three categories, according to the
Regulation (EC) No 1774/2002 laying down health rules concerning animal
by-products not intended for human consumption. Braun & Kirchmayr (2003)
describes the regulation and the possibilities for anaerobic digestion.
In this chapter a very short description of the definition of categories is done,
based on waste management for the mobile abattoir.
Category 1, 2 and 3 materials shall comprise of animal by-products with the
following description, or any material containing such by-products:
Category 1
all body parts from animals suspected of being infected by a transmissible
spongiform encephalopathies (TSE) or in which the presence of a TSE has
been officially confirmed;
specified risk material and where, at the time of disposal specified risk
material has not been removed, entire bodies of dead animals containing
specified risk material;
combination of Category 1 material with either Category 2 material or
Category 3 material or both, including any material destined for processing
in a Category 1 processing plant.
All Category 1 material should be incinerated.
Category 2
Manure and digestive tract content. This fraction can be treated in a biogas-
or composting plant without pasteurisation as a pre-treatment. It can also be
applied directly on arable land;
all animal materials collected when treating waste water from abattoirs
including screenings sludge and materials removed from drains from those
premises. This fraction can be treated in a biogas- or composting plant, if it
has been pre-treated in a sterilisation plant (if the particle size of the fraction
had been reduced to less than 50 millimetres before sterilisation and is then
subjected to at least 20 minutes of temperatures higher than 133 °C, without
interruption, at a pressure of at least 3 bars);
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animals and parts of animals that die other than by being slaughtered for
human consumption, including animals killed to eradicate an epizootic
disease.
This fraction can be treated in a biogas- or composting plant, if it
has been pre-treated in a sterilisation plant (if the particle size of the fraction
had been reduced to less than 50 millimetres before sterilisation and is then
subjected to at least 20 minutes of temperatures higher than 133 °C, without
interruption, at a pressure of at least 3 bars);
combination of Category 2 material with Category 3 material. This fraction
can be treated in a biogas- or composting plant, if it has been pre-treated in
a sterilisation plant.
Category 3 material
Parts of slaughtered animals, which are fit for human consumption in
accordance with Community legislation, but are not intended for human
consumption for commercial reasons;
parts of slaughtered animals, which are rejected as unfit for human
consumption but are not affected by any signs of diseases communicable
to humans or animals;
hides and skins, hooves and horns, pig bristles and feathers originating from
animals that are slaughtered in an abattoir, that undergo an ante-mortem
inspection, and are considered acceptable, as a result of such inspection.
All Category 3 material can be treated in a biogas- or composting plant, if it has
been pre-treated in a pasteurisation plant (if the particle size of the fraction is
reduced to less than 12 millimetres before pasteurisation and is then subjected
to at least 60 minutes of temperatures higher than 70 °C without interruption).
Amounts, composition and classification of waste
Definitions to classify different waste generated at slaughter
In this report, the definitions of different waste fractions generated at slaughter are
mainly based on regulation (EC) No 999/2001 of the European Parliament and of
the council together with the old council directive of the European Communities
90/667/EEC.
Since the EC-regulation 1774/2002 has slightly changed the definitions, we have
tried to refer the waste fractions mentioned to both the old and the new definitions
in the following text.
A. Animal by-products: In this case this fraction includes the entire bodies, parts
of animals or products of animal origin not intended for human consumption,
with the exception of animal excreta. This definition is based on the old council
directive of the European Communities 90/667/EEC.
B. Specified risk material (SRM): Animal by-products suspected of being infected
by transmissible spongiform encephalopathies (TSE) or in which the presence of
a transmissible TSE has been officially confirmed (SRM is a Category 1 material
in regulation 1774/2002). This fraction includes:
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1. skull, including brain and eyes, tonsils, spinal cord from cattle older than
12 months, and the bowels from duodenum to rectum from cattle of all ages;
2. the whole carcass or part of it, if any of the parts mentioned in point 1 are
included;
3. low risk and high risk material handled together with specified risk material.
C. High risk material: Animal by-products that could lead to other serious risks
for man or animal health (high risk material is a Category 2 material in regulation
1774/2002) than those mentioned for specified risk material. This includes:
1. animal by-products including blood originating from animals which show,
during the veterinary inspection carried out at the time of slaughter, clinical
signs of diseases communicable to man or other animals;
2. all those parts of an animal slaughtered in the normal way which are not
presented for post mortem inspection, with the exception of hides, skins,
hooves, feathers, wool, horns, blood and similar products;
3. all meat of animal origin which are spoiled and thus present a risk to human
and animal health;
4. low risk material being handled together with high risk material.
D. Low risk material: Animal by-products not defined as specified risk material
or high risk material. This fraction is a Category 3 material in regulation
1774/2002.
E. Content in stomach and intestines: This fraction includes manure and
digestive tract content and is a Category 2 material in regulation 1774/2002.
F. Blood: In this study, all collected blood is defined as an animal by-product and
is a Category 3 material in regulation 1774/2002.
G. Tibial and fibular bones: in this study, it is an animal by-product and a
Category 3 material in regulation 1774/2002.
Pig slaughter
In the following example, the slaughter capacity is assumed to be 700 pigs per
week. The daily amount of waste produced and the content of plant nutrients in
the waste fractions are given in Table 2.
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Table 2. Calculated daily amount, kg/day, of animal by-products and stomach and
intestinal contents during slaughter of pigs with a capacity of 700 pigs per week. The
composition of plant nutrients in the waste fractions is also included. Weight of the bowels
is excluded due to lack of data. DM gives the amount of dry matter included in the given
amount. OM gives the amount of organic matter included, i.e. DM minus the content of
ashes.
kg/day Amount DM OM N P K
Animal low risk material, excl. blood 1 698 526 477 47.9 7.4 2.3
Blood 319 61 58 8.5 0.1 0.3
Stomach and intestinal contents 686 69 58 2.1 1.4 1.7
Sum 2 702 655 590 58.4 8.9 4.2
Animal high risk material 100 31 28 2.8 0.4 0.1
Cattle slaughter
In the following example, the slaughter capacity is assumed to be 70 adult cattle
per week. The daily amount of waste produced and the content of plant nutrients
in the waste fractions are given in Table 3.
Table 3. Calculated daily amount, kg/day, of animal by-products and stomach and
intestinal contents during slaughter of cattle with a capacity of 70 adult animals per week.
The composition of plant nutrients in the waste fractions is also included. Hives are not
included. DM gives the amount of dry matter included in the given amount. OM gives the
amount of organic matter included, i.e. DM minus the content of ashes.
kg/day Amount DM OM N P K
Animal low risk material, excl. blood, tibial
and fibular bones
1 086 337 303 30.6 4.7 1.4
Tibial and fibular bones
1)
82 44 28 2.9 0.4 0.1
Blood 181 34 33 4.8 0.1 0.1
Stomach and intestinal contents 932 98 87 2.2 0.7 0.8
Sum 2 281 513 452 40.6 6.0 2.6
Specified risk material 380 151 110 11.1 1.7 0.5
Animal high risk material 50 16 14 1.4 0.2 0.1
Sum 430 166 124 12.5 1.9 0.6
1) Regarded as unsuitable for biological processing due to the need for crushing before treatment.
Waste handling during cattle slaughter will probably be more expensive than
during pig slaughter because intestinal content, tonsils, scull and spinal cord must
be handled according to the rules for specified risk material.
Use of water
In Sweden, the use of water in large-scale stationary abattoirs is reported to be
between 7 and 14 m
3
per product tonne. A small Swedish abattoir, that does
not clean the stomach or intestines, consumes 1.4-1.5 m
3
per product tonne
(pers. comm. Hellström). The use of water in a mobile unit is 4-5 m
3
per day
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(pers. comm. Sandstöm, 2001). With the capacities suggested in Tables 2 and 3
above, the mobile abattoir will consume around 1 m
3
per product tonne or less.
Collecting and pre-treatment of waste in the mobile unit
The only mobile abattoirs in use in Sweden are those for reindeer slaughter.
Legislation for this operation differs a lot compared to other kinds of slaughter.
For instance, burial of waste is in practice.
The waste from mobile abattoirs could be managed according to the following
suggestions:
Irrespective of how the waste is to be sorted, the abattoir would have a separate
waste unit managed by only one member of the personnel. This person should
not take part in the slaughter and not enter the compartments where slaughter is
performed before accurate cleaning and change of clothes is undertaken.
Dependent on how the waste is to be processed, incinerated or biologically
treated, the design of the waste management unit may be different.
Handling of specified risk material, high risk material and tibial and
fibular bones from cattle
It is assumed these fractions are incinerated in all situations. They should be
collected in a separate container with a lid, sorted according to the waste treatment
unit and labelled with a colouring matter or other type of marker. It should be
possible however, to add the SRM fractions, produced in the slaughter compart-
ment, to the container without having to leave that area. The intestines are
emptied before being placed into this container. The particle size of these
fractions has to be reduced by a grinder before incineration.
Since the tibial and fibular bones of cattle also need to be crushed and ground
before incineration, it is considered most rational to handle them together with
the SRM, although the tibial and fibular bones are not risk material.
Low risk material
Soft parts and bones, tibial and fibular bones from cattle are excluded:
If it is to be treated biologically, these fractions have to be ground in the
mobile’s waste unit. The ground material shall be collected in a separate
container together with the blood.
If it is to be incinerated, the grinding could take place wherever it is
considered cost effective.
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Content in stomach and the intestines
Cattle
The stomach and the intestines are emptied and the digestive tract content is
collected. Foreign objects, like bale twine and metal pieces, are removed to
prevent stoppage of the mechanical equipment later on. One way to do this is
to produce a slurry by adding water and subsequently separating these objects
through a screen. Then the slurry and the manure can be handled together. If
biological treatment is included in the waste management system, this fraction
is handled together with the ground animal low risk material. Otherwise, the
low risk material is deposited into the manure storage at the farm.
Pigs
In systems with a biological treatment unit, the stomach and the intestines are
not emptied before grinding. In systems with local incineration, emptying could
be preferred in order to raise the heat value.
Wastewater
Wastewater is collected and screened for particles. The particles are defined as a
Category 2 material. The water is handled together with the manure and digestive
tract content.
Storage and transport
To have a cost-effective organisation, the collected waste materials will often
have to be stored on the farm for a day or two. It might therefore be necessary
to use several small sealable containers.
Fractions with the option to be placed in the farm manure storage
Manure, digestive tract content and screened wastewater could be put in the
farm manure storage. The content of nutrients and energy in these materials are
proportionately small. Economic considerations will determine whether these
fractions are to be used on the farm or transported away from the farm.
Methods for treatment of slaughter waste
In conventional stationary abattoirs, the animal’s by-products are transported to
one centralised plant for production of meat meal or biogas where materials from
different origins meet. Obviously, waste from a mobile slaughter unit could be
integrated in such a system.
Composting
Composting is a biological method to hygienize and stabilize the waste, i.e. make
it more homogeneous and dry and thereby more easy to handle.
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Liquid composting
Wet composting has been tried on black water, food waste and manure for
instance, but so far not on animal by-products, which is why it is necessary to
research before starting this practice. It is, however, in the context of mobile
slaughter, a very interesting method. This is due to the possibility of working
locally in a moderate scale in combination with the circulation of nutrients.
Composting of solids
With this method, slaughter waste is composted together with material that has
higher carbon content, straw for instance. The optimal mixture of straw and waste
is expected to be about 50/50 on mass base. Probably, water will have to be added
often too to avoid excessive drying.
A disadvantage with solid composting is a considerable loss of nitrogen through
ammonia emissions. Also, for hygienic reasons the material will most likely have
to be treated with heat separately. The production of heat in the solid compost will
not be sufficient to keep the material at or above 70° C for a minimum of one
hour, which is required according to EU-regulations.
Anaerobic digestion
Anaerobic digestion will stabilize the waste and make it useful as a nutrient in
farming. During the process, a gas is produced. The gas is composed mainly of
methane, a fuel of high value, which is possible to use, after refining, in vehicle
motors. This gas could also be used to produce the heat and hot water needed for
the process without refining. The net energy output, after reduction for efficiency
losses in the boiler and heat used for the process, is estimated to be in the region
of 2 MWh/day in hot water (rate 70 cattle/week, about 3 MWh/day with 700
pigs/week).
With the anaerobic digestion, the material will also have to be heated to 70°C
in a separate pre-treatment step. Anaerobic digestion of slaughter waste in
combination with other wastes is a relatively common practice. However, this
waste alone has not been well studied from what we know.
Local incineration
Incineration (burning) is a thermal method for hygienisation and stabilization
of waste. With incineration, the nitrogen will be lost in the form of exhaust gas
through the chimney. The phosphorus and potassium in the waste will end up
in the ashes, which could be used as fertiliser.
The lower calorific heat value of carcasses with 35 % dry matter content is 8.7
MJ/kg raw material (Schuster & Sundquist, 2001). Before burning, the material
has to be crushed and ground. Then, it is suggested that sawdust and vegetable oil
is added. After that, the heat value is approximately 8.0 MJ/kg raw material in
the case of cattle (6.7 in the case of pigs). The net energy output, is estimated to
be 3.4 MWh/day in hot water (rate 70 cattle/week, about 4.7 MWh/day with 700
pigs/week). Combustion of dried meat meal is a well-known technique, while
combustion of wet slaughter waste has only been performed in small trials.
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Economy
Stationary slaughter houses
Hermansson (1996) studied the economics of Swedish stationary slaughter. The
study was based on the bookkeeping from 14 companies. The results showed that
this kind of activity has obvious advantages in being organised in large-scale
units. The three most important factors for the economic results were found to be:
size of the abattoir,
rate of cost reduction overtime,
composition of animals slaughtered (i.e. cattle/pigs/other animals).
Cattle were more expensive to slaughter per weight unit than other animals.
Mobile slaughter units
Helgesson (2000) presented a comparison between stationary and mobile
abattoirs. The cost for the stationary activity was taken from Hermansson (1996)
and transportation costs were added.
Transportation costs vary, between different regions in Sweden, due to different
density and size of animal farms. While the cost was found to be 0.35 SEK/kg
slaughtered weight in the south of Sweden, it was 0.93 SEK/kg slaughtered
weight for a company in the north.
Table 4 presents real costs for today’s stationary abattoirs based on the works
of Helgesson and Hermansson and estimated costs for mobile slaughter in three
regions of Sweden (Benfalk et al., 2002). The costs for mobile slaughter are
mainly based on data from the Swedish manufacturer of mobile units. Costs for
transporting the animals, calculated for Swedish conditions, are included in both
systems.
Table 4. Real costs (SEK/kg slaughtered weight) for today’s stationary slaughter system
and calculated costs for mobile slaughter in three regions of Sweden (Benfalk et al.,
2002).
North Middle South
Stationary today 4.51 2.93 2.81
Mobile, cattle 4.80 4.76 4.78
Mobile, pigs 3.10 3.06 3.08
As already mentioned, the cost for today’s stationary slaughter abattoirs differs a
lot between regions. In this study, the cost differences between mobile slaughter
abattoirs are smaller. However, with mobile slaughter the density of farms is also
of great importance. In regions with many small, sparsely situated farms, a lot
of time will be spent on setting up and packing up the unit as well as travelling
between the farms.
The amount of meat produced in the mobile per year is of crucial importance for
the economy, Figures 4 and 5.
JTI – Institutet för jordbruks- och miljöteknik
41
Figure 4. Calculated relation between the capacity (number of cattle per day) and cost of
slaughter (SEK/kg), example of conditions in the middle of Sweden.
The calculations for Figures 4 and 5 were based on the assumption that 5 hours
per day were available for slaughter after the time for transportation, set-up,
cleaning, breaks, etc had been drawn from 8 hours. A slaughter rate of 30 pigs or
5 cattle per hour could be possible with 5-6 personnel but since the chill section
has a limited holding capacity, only 23 cattle or 120 pigs was calculated per day.
Figure 5. Calculated relation between the capacity (number of pigs per day) and cost of
slaughter (SEK/kg), example of conditions in the middle of Sweden.
The full cost for personnel was calculated independently on the number of kg
slaughtered per day. However, if there was alternative work for the personnel with
e.g. meat cutting and packing on days with few animals to slaughter, the slaughter
cost could be reduced (compared to Figures 4 and 5).
0
2
4
6
8
10
12
9 12151821242730333639424548
Slaughter capacity, cattle/day
Slaughter cost, SEK/kg
0
1
2
3
4
5
6
7
50 60 70 80 90 100 110 120 130 140 150
Slaughter capacity, pigs/day
Slaughter cost, SEK/kg
JTI – Institutet för jordbruks- och miljöteknik
42
Case study
In the Case study (Benfalk et al., 2003) concerning pigs, a theoretic remodelling
of the delivery structure was made to fit a mobile abattoir. Initially, the slaughter
deliveries from 11 farms that were connected to the same sow pool were investi-
gated. The farms delivered on average 2 721 pigs (from a min of 1872 to a max
of 5056) during 2001. The average delivery from all the farms per week was
576 pigs (min 255 – max 1317). The aim of the theoretic remodelling was to come
close to the average slaughter delivery without changing the delivery by more
than one week. The aim was also to move the mobile abattoir a maximum of two
times per day (that is slaughter at two different farms on the same day).
The result of the remodelling was that on 78 % of all slaughter days the mobile
could slaughter one whole day or more at the same farm (Figure 6).
Figure 6. Number of days the slaughter could continue at the same farm.
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... Gemensamt för alla mobila slakteriers utformning är att det behövs två transporter, en för bedövning, slakt och nedkylning och en för transporten av de kylda slaktkropparna. Det måste även finnas tillgång till vatten av dricksvattenkvalitet och i tillräcklig mängd (Benfalk et al., 2005). Detta för att kunna rengöra utrustningen ordentligt efter användning. ...
... Processen börjar med att en veterinär utför en levandedjurbesiktning på gården. Detta ska ske högst 24 h innan slakt (Benfalk et al., 2005). Därefter drivs djuren till uppsamlingsplatsen. ...
... Det finns två alternativ till utformningen av uppsamlingsplatsen. Den ena innebär att djuren tas från stallet till små väntboxar där de står upp till en halvtimma innan slakt och det andra alternativet är en större vänthall med flera boxar, där djuren kan stå upp till en halv dag (Benfalk et al., 2005). Från uppsamlingsplatsen kommer djuren till bedövningen, som sker på olika sätt beroende på vilket djurslag det gäller, till exempel genom gasning, bultning eller med elektricitet. ...
Article
Undersökningar visar att det är mycket problem att tillgodose djurens välfärd vid konventionell slakt gällande transport, uppstallning och hantering (Broom, 1993). Därför är det intressant att ta reda på vilka alternativ det finns till konventionell slakt. Ett exempel är mobila slakterier. Det här arbetet tar upp dess för- och nackdelar ur djurvälfärdssynpunkt. Det finns idag många rapporter, som tar upp mobil slakt ur en ekonomisk synvinkel (Helgesson & Pettersson 2000) och den praktiska hanteringen (Benfalk et al., 2002) efter avlivningsmomentet men mindre om hur djurens välfärd påverkas. Det finns olika utformningar på mobila slakterier. Idag används de bara till renslakt i Sverige men idéer och ritningar finns även för andra djurslag. Eftersom nöt, svin, får och höns/kycklingar är de vanligaste produktionsgrupperna i Sverige, har vi valt att fokusera på dem. Anpassningar i det mobila slakteriet måste göras för det speciella djurslaget, därför att deras förutsättningar skiljer sig åt, för att få en effektiv hantering och slakt. Detta skulle i sin tur kunna leda till bättre välfärd för djuren. De största problemen som ses inom slaktprocessen idag är framför allt stress och fysiska skador. Detta är någonting som inte bara påverkar djuren utan även oss konsumenter, då köttkvalitén påverkas om djuret har en dålig välfärd.
... However, the authors also concluded that new small-scale abattoirs offer little in terms of shortened driving distances and improved animal welfare unless the plants are located strategically. In regions with very small and sparsely located farms, a lot of time will be spent between the farms and setting up the mobile unit, which makes it less viable [102]. Hultgren et al. conducted risk assessment of animal welfare in connection with Nordic small-and large-scale sheep slaughter and found that welfare risks appeared to be lower for small-scale slaughter for most factors (hazards), but the opposite was true for factors involving regrouping and handling of single animals [103]. ...
... Personnel skill and experience in handling animals and equipment were considered to be decisive. Benfalk et al. emphasized the importance of adequate conditions for the mobile plant to connect to the animal housing facilities, a permanent and easily cleanable docking unit which can be locked up with doors, and skilled personnel with adequate continuing education [102]. The authors also underlined that the management should be well-educated in good animal and food handling and in staff supervision, and be in close contact with the practical work at the mobile unit. ...
... A major negative aspect, however, is the limited space, which restricts the working area for manual handling. The limited availability of water may also affect the staff negatively [102]. ...
Article
Large numbers of livestock are transported to slaughter. The journeys may cause considerable animal stress and suffering. They often involve separation from familiar groups and places, as well as exposure to a range of stressful stimuli. Stockpersons do not always understand the principles of efficient interaction with the animals and may have undesirable attitudes towards them, which worsens handling. This paper reviews the literature on farm animal transport to slaughter, its consequences and alternative approaches. On-farm slaughter may be conducted at a small stationary plant located on farm, at a mobile slaughter unit temporarily placed at or near the farm or by on-farm killing followed by transport of the dead animal to a nearby plant for further processing. On-farm slaughter has the potential to reduce pre-slaughter animal stress and improve meat quality by shorter or eliminated journeys, minimal exposure to unfamiliar environments, animals and persons and less time in lairage. This would be perceived as an improvement in relation to some of the practical and ethical issues linked to the slaughter of animals. However, research and development is needed for wider application of mobile slaughter and on-farm gunshot stunning. Issues related to animal welfare, food and occupational safety, waste management and public health should be investigated further.
Article
Full-text available
Twenty-three reindeer bulls, aged 2-3 years, fed during two winter months at the Vuolda reindeer research station in Arjeplog, Sweden, were used in the study. The first group of eight reindeer was moved from their feeding corral to a selection corral, captured by lasso and stunned with a captive bolt outside the selection corral. The second group of seven reindeer was moved to the selection corral, captured by lasso and restrained, after which they were loaded onto a lorry- and transported for 1 hour and then slaughtered. The third group of eight reindeer was moved to the selection corral and herded directly onto the lorry, without any manual handling. They were transported for 5 h and then slaughtered. In both transport groups, four reindeer were fitted with pre-programmed automatic blood sampling equipment (ABSE). ABSE sampled blood at predetermined times via a jugular vein catheter. Ultimate pH-values in three muscles (Mm. longissimus, triceps brachii and biceps femoris) were significantly lower in the group carefully handled and transported for 5 h compared with the other two groups. The physiological mechanisms behind these results are discussed. Samples from M. semimembranosus were collected at slaughter and after 2, 6 and 10 days of refrigerated storage (+4 °C). The samples were analysed for total counts of aerobic bacteria (pour-plated in Tryptone Glucose Extract Agar, Difco, incubated at 20 °C and 30 °C, respectively for 72 h), coliform bacteria 37 °C (pour-plated in Violet Red Bile Agar, Oxoid, incubated at 37 °C for 24 h), Enterococci (surface-plated onto Slantez and Bartley Agar, Oxoid, incubated at 44 °C for 48 h) and Bacillus cereus (surface-plated onto Blood Agar Plates (Blood Agar Base, Difco, supplemented with 5% defibrinated horse blood) 30 °C for 24 h). All samples fell in the range 'fit for consumption'. At slaughter, there was no difference in ASAT activity, urea and Cortisol concentrations between the two transported groups. However, the plasma ASAT activity and urea concentrations at slaughter were significantly lower in the non-transported group. In both transport groups, the plasma Cortisol concentrations increased during loading onto and unloading from the lorry. Abomasal lesions were observed in all treatment groups. It was concluded that reindeer showed an acute stress response to manual handling and transport.
Article
Pigs from crosses of a Piétrain (Pi) and a Large White×Piétrain (LwPi) heterozygous (Nn) boar lines with Landrace×Large White homozygous negative (NN) sows, were used to study the effect of halothane gene and pre-slaughter treatment on animal welfare and meat quality. A total of 83 gilts (47 NN and 36 Nn) were assigned to a long treatment (3 h 15 min transport and 12 h lairage) and 73 (39 NN and 34 Nn) to a short treatment (30 min transport and 2 h lairage). Heart rate was recorded throughout loading and transport. Blood samples were collected before loading, after transport, and at exsanguination to measure cortisol, creatine phospho-kinase (CPK) and lactate dehydrogenase (LDH). Carcasses were classified and commercial cutting was carried out. Meat quality was assessed on the Longissimus thoracis muscle by measuring electrical conductivity (PQM), colour (Minolta CR 200 and Japanese scale) and ultimate pH. Loin drip losses were assessed at 24 h. Halothane carriers showed a higher increase in cortisol levels after transport and exsanguination in the long treatment (P<0.05) as well as in LDH and CPK after exsanguination in the short treatment (P<0.05). In this treatment, halothane-free pigs recovered during lairage when comparing LDH and CPK increases after exsanguination to their increases after transport. No effect of the halothane gene on heart rate was observed. Pi sired pigs were leaner and had higher yields of leg and loin compared with LwPi sired pigs (P<0.001), but no differences in meat quality were observed between crosses. Halothane carriers had a higher estimated lean content (P<0.01) and shoulder and leg yields (P<0.01), but poorer meat quality than non-carriers (i.e. higher incidence of PSE meat, P<0.001). Although pre-slaughter treatment and halothane genotype did not significantly affect pHu, significantly higher L*, a* and b* values found in the short treatment and Nn individuals indicated paler meat. These results suggest that for improving meat quality and welfare the halothane gene should be removed from breeding schemes.
Article
The experiment compared meat quality in carcasses from pigs subjected to the absolute minimum of stress preslaughter with that from carcasses of pigs subjected to simulated commercial handling. A total of 120 pigs (85 kg) were used. They were a commercial hybrid and were processed in six equal batches. The minimal stress group were slaughtered with as little stress as possible. The simulated commercial handling group were mixed and transported for 2hr (80 km) and lairaged for 30 min. Simulated commercial handling increased plasma cortisol, plasma lactate, CPK and beta-endorphin. Muscle temperature measured in the m. longissimus dorsi (LD) at 45 min increased as did the ultimate pH in the m. adductor (AD). Overall eating quality was not affected. There were batch affects on most variables. Males were leaner and produced meat that had greater abnormal fat odour, darker cooked colour, poorer pork flavour, lower overall acceptability and was tougher.
Intramuscular pressure and muscle blood flow was measured in the supraspinatus muscle in 6 healthy subjects. The recordings were performed at rest, during isometric exercise, during an isometric muscle contraction of 5.6 kPa (42 mm Hg) and 10.4 kPa (78 mm Hg) and at rest after the contraction. Intramuscular pressure was measured by the microcapillary infusion technique, and muscle blood flow by the Xenon-133 washout technique. Intramuscular pressure was 38.2 kPa (SD 12.0) (287 mm Hg) during maximal voluntary contraction. A muscle contraction pressure of 5.6 kPa (42 mm Hg), which is 16% of maximal voluntary contraction, reduces local muscle blood flow significantly. It is concluded that the high intramuscular pressures found in supraspinatus during work with the arms elevated impedes local muscle blood flow.
Article
Pigs weighing approximately 60 kg were stunned electrically (90 V, 50 Hz, 15 seconds) and exsanguinated normally or after the heart had been stopped by inducing ventricular fibrillation. The efficacy of this treatment was checked by monitoring the electrocardiogram. Cardiac arrest did not affect the weight of blood lost, the rate at which it was lost or the amount apparently retained in the carcase.
Article
This study employed a choice experiment (CE) to ascertain consumer preferences and willingness to pay (WTP) for non-market food product quality attributes. Data were obtained from a large mail survey and estimated with a random parameter logit model. The results indicate that Swedish consumers place greater monetary worth on the use of mobile abattoirs for cattle than for pigs, and even place a negative monetary value for mobile abattoirs in broiler production. We show how CE data can be used to estimate individual WTP, using a random parameter logit model. We find that there is a substantial difference in heterogeneity between consumers WTP for mobile abattoirs for the types of livestock included. Based on estimated distributions of WTP and available cost estimates, the market share for mobile abattoirs is predicted. The approach taken is vital to agribusinesses intending to serve specialized niche markets. Our results are useful for forming product differentiation strategies within the food industry as well as for the formation of food policy.
Meat Quality in Pigs Subjected to Minimal Preslaughter Stress Consumer willingness to pay for farm animal welfare-transportation of farm animals to slaughter versus the use of mobile abattoirs Working paper in Economics no
  • S N Brown
  • P D Warriss
  • G R Nute
  • J E Edwards
  • T G Knowles
  • F Carlsson
  • P Frykblom
  • C J Lagerkvist
Brown, S.N., Warriss, P.D., Nute, G.R., Edwards, J.E. & Knowles, T.G. 1998. Meat Quality in Pigs Subjected to Minimal Preslaughter Stress. Meat Science 49:3, 257-363 Carlsson, F., Frykblom, P. & Lagerkvist C. J., 2004. Consumer willingness to pay for farm animal welfare-transportation of farm animals to slaughter versus the use of mobile abattoirs. Working paper in Economics no. 149, November 2004, Department of Economics, Gothenburg University, Sweden
Prevalence of persistent shoulder pain and subacromial pain syndrome among slaughter house workers. Second International Scientific Andersson Värdering av griskött på en lokal marknad – ur ett konsumentperspektiv. JTI-rapport nr 325
  • J H Anderson
  • P Frost
  • H Christensen
  • C Lagerkvist
  • J Carlsson
  • F Hannerz
  • N Lindgren
  • K Frykblom
Anderson, J. H., Frost, P. & Christensen, H., 1995. Prevalence of persistent shoulder pain and subacromial pain syndrome among slaughter house workers. Second International Scientific Andersson, C., Lagerkvist, C.,J., Carlsson, F., Hannerz, N., Lindgren, K., Frykblom, P. 2004. Värdering av griskött på en lokal marknad – ur ett konsumentperspektiv. JTI-rapport nr 325, Lantbruk och Industri Arbetsmiljöverket. 2001. Arbetsskador 2000 -Preliminära uppgifter. Statistiska meddelanden. Arbetsmiljöverket, Statistiska centralbyrån. AM 69 SM 0101.