Systems of pig production

Small-scale pig production systems

Scavenging or Extensive Small-scale System 

This is the traditional system of rearing pigs in most parts of the tropics. 

It is also the simplest and cheapest. Each family, kraal or village keeps a few stocks which are allowed to wander freely and pick up food when and where they can. If extra food is available, they may receive 

supplementary food. This supplementary food will generally consist of foods of low nutritional quality such as banana, crop residues, water hyacinth, and rice bran, local herbaceous plants, by products of beer�making or kitchen wastes. Where pigs are particularly valued for festival or ritual slaughter, as in parts of Asia and Africa, a few may be confined and fed for a three-to-six month fattening period prior to important ceremonies. 

Indigenous breeds of pigs predominate on the scavenging system; because they are adapted to the local environment and their relatively small size and mobility render them best able to cope with the conditions. Productivity is normally low with the erratic and often seasonal food supplies resulting in irregular breeding of female animals, high rates of offspring mortality and low growth rates. Stocks raised on this system are particularly susceptible to infestation with parasites, and invariably carry a heavy burden of intestinal worms and ectoparasites. A 

particularly hazard of the scavenging system is that animals have access to sources of parasites, e.g. human waste, which can then be transmitted back to man when he eats meat. 

The majorities of scavenging domestic pigs are owned by subsistent farmers, and are not produced with any particular market in mind. 

Rather the animals play an important socio-economic role as a form of bank, and stock are sold at times of cash shortages or unexpected needs in the family. The numbers are usually kept small, in the region of 1-10 breeding females per herd. 

Semi-intensive production 

In these systems, often also known as ‘backyard’ systems, animals are confined and therefore present a commitment on the part of the farmer to feed his stock. Pens or sites are mainly of very simple construction and in some countries of south East Asia and West Africa, may be made of bamboo and elevated. Of the other hand, animals are sometimes constrained by tethering in larger yards or paddocks. 

Feeding is based on kitchen waste, vegetables and by-product foods, and 

management is generally minimal. As a consequence, productivity tends to be relatively low and mortality can be high. Although local and indigenous breeds of animal predominate, crosses between indigenous and exotic breeds can be found in this system of production throughout the developing world. Marketing is largely indiscriminate and is dictated by the immediate financial needs of the owner. Generally, herd sizes and 

productivity tend to be higher in these systems than in the scavenging systems. 

Intensive production 

These systems are characterized by the fact that the small-scale producer has moved away from subsistence production to the commercial pig production. Units may comprise up to 50 head, and the producer will grow and/or purchase food specifically for his pig enterprise. The 

system of housing becomes more sophisticated shade and open space, and appropriate feed and watering facilities. In order to justify the increased capital cost, the farmer will attempt to manage his stock to optimize output, including some veterinary protection against parasites 

and diseases. The breed of animal raised will tend to be mainly the higher-performance exotic, or a cross between exotic and indigenous breeds. Marketing may be informal, through local butchers, or into the large-scale commercial sector, but in any event it will be planned to bring in a regular income for the enterprise. 

Large-scale systems 

Intensive 

This is the most common system of large-scale production. Units are generally capital intensive and may involve a large herd from 40 up to 1000 heads. Modern high-performance breeds of pigs, or hybrids, are used, and provided as far as possible with optimum conditions of housing, feeding and management in order to ensure maximum output. 

Housing will often be designed specifically for the different classes of stock and environmental conditions. 

These units, especially the larger ones, are particularly amenable to integration with grain production and stock feed manufacturing operations on the one hand, and processing and marketing on the other. 

The farm animals will invariably be marketed through a processor in order to maximize returns on the carcass. 

Extensive systems 

These are a trend throughout Europe and America towards less intensive systems of production. These systems, often known as ‘outdoor’ systems, entail keeping animals in paddocks or ranches and providing individual pens for parturition and shelter. Younger stocks are generally 

raised under more intensive conditions. In Europe, hybrid crossbreds, with a greater ability to withstand climatic vagaries, are produced specifically for use on this type of system. 

Production systems of this type exist in the tropics, and there is clearly potential for further expansion. The major advantages when compared with intensive systems are that less capital is required for establishment, and animals can gain access to bulky foods such as pastures, crop residues, cassava roots and sweet potatoes. In tropical regions it is 

essential that adequate shade and housing be provided. Moreover, there must be tight control of parasites and adequate fencing to prevent contact with endemic disease, e.g. in Africa, contact with wild animals and avoid transfer of diseases. 

Integrated systems 

The integration of pig production with other ancillary enterprises has long been widely practiced in tropical Asia, involving various combinations, fish farming production of algae, methane gas generation, duck water hyacinth and vegetable production. Such bi-or tri-commodity operations enhance the efficiency of resource use and increase output for the overall operation. 

For instance fertilizing fish ponds with pig manure and effluent, algae are generated which can then be utilised by fish. As long as sufficient water is available for suitable fish ponds, pig sties can either be constructed above the ponds so that the manure can drop straight into the water, or close by so that the effluent can be channeled into the ponds. The various species of Tilapia spp are the most commonly used fish, often mixed with small populations of carp (cyprinus spp) and catfish (clarias spp) or other predators. Fifty to sixty pigs produce 

sufficient effluent for one hectare, fishpond, which, if stocked at between 20 000 and 50 000 fish per hectare, can produce annual edible fish yields or 3.5 to 5 tonnes per hectare. 

In some countries, water hyacinths used to harvest nutrients from the fishponds, and this is then fed back to the pigs. Alternatively, the nutrient-rich water can be used for irrigating vegetables, or in other 

systems. Ponds can be dried in rotation and vegetables grown in the dry pond beds. In another alternative system, where other food is available, the pig effluent is used to produce algae, which is then harvested and dried and fed back to pigs or other livestock. If the pig effluent is 

insufficient for any particular system, ducks can be used to augment the fertilization of the ponds with their manure. 

The solid fraction of animal, especially poultry, manure can be used as an effective fertilizer for crops, particularly if it is properly composted, and this may prove to be the most cost-effective use of the by-product. 

A further important development has been the anaerobic fermentation of farm animal effluent for the production of methane gas. Relatively simple digesters can produce a steady source of methane which can be used as a means of energy for domestic or agricultural use. These 

digesters are now in use in rural areas throughout the developing countries of Asia, and it is estimated that seven heads of pig for example will provide enough dung to ensure the supply of sufficient methane for house fuel for a family of five.