Components of slaughterhouse

1. Lairage

Generally, the lairage should be sized to hold the expected daily kill. This will allow stock to be held overnight before slaughter. In some special cases a greater capacity may be required although the holding of stock at the abattoir for an extended period before slaughter should not be permitted.

Pen areas required for each species are as follows:

Cattle:        1.7m2/head

Pigs/Sheep:0.35-0.56m2/head

Goats: 0.25m2/head

Poultry : 10- 15 birds per square metre

The lairage shown in the model has been sized to accommodate 4 cattle in two pens of 2 each and 28 pigs or sheep in four pens of 7 each. In localities where animals, particularly cattle, are normally tethered, a larger area without dividing fences may be preferred to allow tethering rather than penning of animals.

2. Slaughter hall

• Slaughter floor

The slaughter halls and ancillary accommodation thus provided shall be separated, keeping in view the economic and local requirements, by solid walls depending upon the site. The slaughter hall shall have the following facilities.

The floor should be managed on the basis of the size of animals.

Cattle

The animal is led into the bleeding area where it is restrained by a tether through the floor ring prior to stunning (using a captive bolt pistol). After stunning the animal is shackled by one leg and hoisted, with a rope pulley block. The animal is then stuck and allowed to bleed in this position and the blood collected in a drum for disposal. Once bleeding is complete the head can be removed and the animal lowered onto the cradle for dressing. The feet are then removed, the skin opened up along the breastbone and the hide partially flayed. Leg hooks are then attached and the carcase raised to a ‘half-hoist’ position on the spreader. Flaying can then be completed and the hide removed. The paunch can then be removed to the inspection buggy and the red offals (including lungs if treated as edible) placed on hooks or the inspection table for inspection. After inspection the carcase can be split and quartered, the quarters being individually hung on the low rail. Once the carcase has been partially flayed and half-hoisted a second animal can enter the bleeding area.

Pigs

Pigs are first stunned in the stunning area then hoisted for sticking and bleeding and then transferred to the scald tank. After scalding for approximately five minutes at 60°C the carcase is removed to the scraping table. After scraping a gambrel can be inserted into the hind legs and the carcase transferred to the overhead rail for final scraping and evisceration. Once a pig is clear of the scraping table the next pig can be placed in the scalding tub.

Sheep and Goats

These would be slaughtered and dressed on the rail in the pig area in a similar manner to pigs. The scraping table is removed to one side during processing of sheep and goats.

• Stunning section There shall be a separate area designated for stunning the animals depending on the species.
• Bleeding section A curbed-in bleeding area of adequate size shall be provided. It shall be so located that the blood shall not be splashed on other animals being slaughtered or on the carcass being skinned. A floor wash point should be provided for intermittent cleaning
• Skinning section Flaying of carcasses shall not be done on floor. Adequate means and tools for dehiding or belting of the animals shall be provided. Means for immediate disposal of hides or skins shall be provided. Hides or skins shall be immediately transported either in a closed and appropriate carriage or by a chute provided with self-closing door to a room where they shall be held before moving to the preservation area. Means for immediate disposal of legs, horns, hooves, etc, should be provided. Floor wash point and adequate number of hand wash basins with sanitizer and cutting equipment sterilizer shall be provided in this section.

• Dressing section

• Evisceration section: For cattle either a mechanical evisceration table or individual paunch/gut holders can be used for the reception and inspection of these products. Facilities shall be provided for the eviscerator to do the job hygienically. In the case of a mechanical conveyor belt, boot washing, apron washing and other washing/sterilizing facilities shall be made available. The evisceration platform used at smaller slaughter house shall be provided with a hand basin/sterilizer. In all cases there shall be facilities for the sterilization of the evisceration platform or offal containers. Racks and/or facilities for handling red and green/rough offal shall be provided.
• Carcass splitting: Appropriate carcass splitting equipment shall be provided in the slaughter house. Carcasses shall be split straight down the middle as appropriate so as not to damage to the meat applicable for beef and pork carcasses.
• Carcass washing area: Water at sufficient pressure shall be provided to remove all blood, slight blood marks, bone, dust and marrow.

3. Isolation block/ emergency slaughter unit 4. Chill rooms 5. Detained/condemned meat rooms 6. Hide and skin store 7. Gut and tripe room 8. Offal room 9. Meat cutting room 10. Vet office & laboratory 11. Despatch room 12. Cloak room 13. Manure bay 14. Effluent plant

3. Chilling room

The chiller shown is a proprietary module with a holding capacity of approximately 300kg and a chilling capacity of 150kg/day. In this size range the use of a prefabricated unit has the advantage that complete assembly and testing before leaving the factory is possible. Also a factory built and tested unit will generally be the lowest in cost as skilled on site work is minimised.

5. Inedibles/Condemned Material: For a plant of the size described here the operation of a by-products plant would not be economic. Two possible methods of disposal suitable for a plant of this capacity are: incineration disposal in a pit (recommended option). Incineration A simple incinerator could be constructed from a used oil drum as described in VPH/83.56.1 In practice however such incinerators are difficult to operate and require substantial quantities of fuel to ensure adequate destruction of meat and offals. Incineration is therefore not recommended. Disposal Pit The preferred alternative, a disposal pit, is simple to use and once constructed costs nothing to operate. Most of the material placed in the pit will slowly decompose, and for an abattoir of the size described, such a pit will be usable for many years. A suitable pit is detailed in Drawing 12. Construction will however need to take into account ground conditions particularly the ground water level (the pit should not extend below the normal water table). In suitable ground conditions it may be possible to dispense with the lining to the lower portion of the pit. It is particularly important that rain water does not enter the pit hence the walls of the top section of the pit should be solid as shown in the drawing. 1.5.5 Ruminal Contents Particularly in the case of cattle a considerable quantity of ruminal contents has to be disposed of. A compost stack provides a simple and low cost method of disposal as well as providing a useful end product. Dung from the pens, effluent screenings and other wastes may be conveniently disposed of in this way. The addition of waste vegetable material such as maize and cassava stalks, straw etc. will increase the yield of compost and ensure aeration of the stack. A full description of the operation of a compost stack is given in VPH 83.56.1 For the smallest plants a simple compost stack will be adequate, but for larger throughputs, and particularly when a significant number of cattle are to be slaughtered, a permanent compost bunker should be provided as described in VPH 83.56. 1/ Guidelines on Small Slaughterhouses and Meat Hygiene for Developing Countries W.H.O. 1984, page 98. 1.5.6 Blood Blood is a valuable source of protein. However at this scale a by-products plant to produce blood meal could not be viable. Blood should not however be diverted into the effluent system since it will quickly clog up the screens and disposal trenches. By using the following treatments blood can be incorporated into stockfeed. It must be stressed that even if the treated blood must be given away this is still preferable to disposal of blood on site. (In the event that blood cannot be disposed of as stockfood a separate blood sump, similar to the solids pit could be constructed adjacent to the slaughterboard. But only as a last resort). Alternative methods of treatment are; Fresh Blood Where pigs and poultry are kept nearby, fresh blood can be directly incorporated into bran, cassava or other stock food. This represents the simplest and most efficient means of disposal. With this method it is essential that the resulting meal be fed out the same day as it has no keeping properties. Lime Treated Blood Where a somewhat longer life for the feed is required approximately 1 % of unslaked (burnt) lime can be added to the blood container and stirred in as the fresh blood is added. The hardened product will keep for up to one week. It should be used as described for fresh blood. Dried Blood Where it is not possible to directly add fresh blood to pig or poultry feed, it may be mixed with bran or cassava as described under (a) and dried in the sun, on either a concrete floor, or matting. Drying will generally be complete in three days. (The drying area will need to be covered in the event of rain). During rainy periods it would be necessary to dry the mixture on corrugated iron trays placed over a copra dryer or similar fire. Because of the additional cost of drying this method is only recommended where the methods described above cannot be used. Since all the methods described above for blood disposal use readily available local materials, construction details have not been provided in this report. 1.5.7 Hides and Skins Three alternatives exist for the disposal of hides and skins: Burial Drying and sale Salting and sale. The quantity and quality of hides and skins will determine whether or not it is worth saving and marketing the hides and skins produced. Where there is only a small cattle and goat kill the costs of preparing hides for sale may well outweigh the returns. In these cases the hides should be disposed of by burial. Each case will need to be assessed individually however as a general guide the export of less than 100 cattle or 500 goat skins per annum is unlikely to be economic. For most abattoirs built to this design this means that exporting will only be economic if hides and skins can be marketed in conjunction with those from other abattoirs. Other factors that would lead to the selection of burial include: Pre-slaughter damage apparent in most animals High shipping costs. Whenever expected returns outweigh costs hides and skins should always be processed for sale. For a single abattoir drying is recommended. Salting should be considered only when production reaches the equivalent of 30 cattle hides per week. This would necessitate the combining of production from several abattoirs and is not discussed further here1. 1 Refer Mann ‘Processing and Utilization of Animal By Products’ FAO, Rome for further detail of salting methods. Drying For abattoirs of this size suspension drying is recommended. Suspension drying can be carried out using locally made equipment and needs no other materials. Where throughput permits a simple a roofed area should be provided for washing and fleshing hides prior to stretching on drying frames. Drying frames for cattle hides should be approximately 3 metres square and can be made of bamboo or small round timbers lashed together at the corners as shown on drawing 18. 1.5.8 Effluent For a plant of this size two options for effluent disposal are practical. Subsurface irrigation Soakage pits Generally subsurface irrigation is to be preferred although where soil conditions are suitable the use of soakage pits may be simpler. The discharge of effluent into water courses or other existing bodies of water is not recommended as this will lead to pollution. Effective waste water treatment, at this scale prior to discharge into water courses is generally impractical and certainly will be more costly than the simple methods of disposal outlined above. Subsurface Irrigation This system is shown on the drawings. Planting of banana palms or paw paw should be made along the trenches to utilize the moisture and nutrients contained in the effluent. Root crops such as taro and cassava should not be planted over the trenches. It is possible only to give general guidance as to trench lengths required. One twenty five metre long trench as shown should however prove adequate in most cases. Provision for a second trench is shown on the layout. If desired the irrigation trenches could be constructed outside the boundary fence so that crop management becomes the responsibility of an adjoining landowner. Root crops should not be grown over the trenches. Soakage Pits Where soil conditions are suitable (i.e. free draining) soakage pits may be used in place of irrigation trenches. No details of construction are presented here. However the importance of adequately covering any soakage pit must be emphasised. It should also be realised that even if wastes are efficiently screened, soakage pits will block up with time. Provision should therefore be made to dig additional pits in the future as the rate of soakage declines. 1.5.9 Stormwater No details for stormwater collection and disposal have been shown on the drawings. Provision will have to be made to dispose of rain water from roofs and paved areas. The most appropriate means of disposal can only be considered once a site has been selected. Local practise should be followed. 1.5.10 Water Supply The importance of a supply of clean potable water cannot be over-emphasised. The plans presented assume connection to a town main or pumped well supply. Hot water for washing has been piped to a single point in the abattoir only. While this will require the use of buckets and brushes for cleaning equipment this system does conserve water. Also cleaning in this manner is more effective than using low pressure hot water hoses. Roof gutters have not been detailed. In areas where a piped water supply is not available roof gutters should be included and water collected into a tank located as shown on Drawing 1. Where tank water only is used provision of an electric pump is most desirable.