In this article we will discuss about:- 1. Introduction to Pig Farming 2. Characteristics of Pigs 3. Development 4. Climate and Pig Production 5. Genetics 6. Nutrition 7. Diseases 8. Housing 9. Improvement in Pig Reproduction 10. Psychic Stress 11. Barriers to Progress.
Introduction to Pig Farming:
There has been very rapid growth in the Australian pig industry over the last 15 years, and there have been major changes in the techniques of production.
Although there are now greater numbers of pigs in Australia than in the sixties, these are raised on fewer pig holdings or farms. At the same time the average number of pigs kept on each farm has increased very greatly.
On most farms in Australia, pig raising is a sideline to some other kind of rural production.
There are now three main kinds of pig holdings:
1. Pig-dairy farms which are mainly found in coastal regions of the east coast and Tasmania. There are now fewer of these holdings because so many dairy farms now sell whole milk and do not have separated milk left over from cream-making to feed to pigs.
2. Pig-cereal farms are mostly located in wheat-sheep areas. Pig numbers on wheat farms doubled between 1960 and 1969 due to such things as cheap grain and the introduction of wheat quotas as well as low wool prices in recent years.
3. Specialist pig holdings are located in many areas, and have become very important in the last ten years. There are two main types: the very large, intensively-managed production units carry more than 1000 pigs, and there are several holdings which now carry 3000 sows each. The smaller holdings are often found near cities and large towns. Several hundred of these holdings carry between two and three hundred sows each.
These specialist piggeries are the ones which have changed the industry so much. Many of the people involved in them have been well-educated newcomers to the industry who have realised that money could be made from pigs if use were made of those modern scientific ideas of pig production being used in Europe and the United Kingdom. As a result, these modern ideas have spread very rapidly.
The new ideas which have changed the pig industry and have made it much more efficient have to do with:
1. Using better systems of feeding.
2. Using better systems of breeding.
3. Using better methods of disease control.
4. Using new ideas about the housing of pigs.
5. Using other techniques that improve the reproduction and growth of pigs.
Characteristics of Pigs:
We are able to manage pigs more efficiently when we understand how different they are from other farm animals. In the first place pigs do not thrive under extremes of climate. They ‘feel cold’ more readily than other farm animals and, being unable to shed their body heat easily, they can suffer acutely from heat stress. On the other hand pigs are able to change the microclimate near them by huddling together when it is cold and stretching out alone when it is hot.
Pigs have a high reproductive rate. With good management it is possible for a sow to have two litters a year, although the Australian average is only 1.7 litters per year. Pigs are non-seasonal breeders.
Though pigs can be very efficient converters of food, it is not true that all pigs are able to make efficient use of it. An aged pig fed on fibrous food may be a very inefficient converter of food into meat. On the other hand, well-fed healthy young pigs can be very efficient converters of food.
Pigs suffer from bullying by other pigs. They will not grow at their fastest rate if bullying is allowed to become severe.
By housing pigs and protecting them from extremes of climate, by housing them in separate pens to reduce bullying, by feeding them well and reducing disease to a minimum some Australian piggeries have raised young pigs with a food conversion ratio of 3:1; that is, these pigs were able to put on one kilogram of flesh for every three kilograms of food eaten. Of course these were young pigs at the stage of fastest growth.
Pigs have short necks. This is the reason that they usually put their feet into water and feed troughs. If a producer wants to prevent his pigs from standing in troughs, he must use troughs of special design.
Since the growth of pigs is very rapid, special names are used for each stage in growth.
Suckers are pigs still with the sow and average about six or seven kg.
Pigs may be sold as weaners three to nine weeks old with a live weight of 10-20 kg.
Slips are pigs 8 to 15 weeks of age that have not put on weight properly and may weigh between 20 and 35 kg, but they may only be as heavy as weaners four weeks younger. Stores are pigs three to five months old weighing 35 to 60 kg. Porkers are quickly-grown pigs which have a live weight of 40-55 kg (and a dressed weight of 27 to 40 kg) when they are four to seven months of age.
It is not a very efficient use of food to kill pigs at this light porker weight when they are growing at a fast rate. So a new idea is to keep these pigs until their live weight rises from 50 to 80 kg when they are known as superporkers.
Baconers are sold at ages varying from 6 to 12 months and when the live weight is 70 to 100 kg (dressed weight of carcase is 55 to 70 kg), but pigs which take 12 months to reach bacon weight are not profitable to the farmer.
A chopper (or back-fatter) is an aged pig which has been fattened off to a weight of 80 to 360 kg.
A boar is a male pig and a barrow is a castrated male. A female pig is a sow and a maiden sow is called a gilt.
We must now study some of the ways in which pig production may be made more efficient.
Development of Pigs:
Pigs are an important source of the supply of protein rich meat-pork. They are prolific breeders and are good converters of farm by-products and kitchen waste and with some supplemental feeding with coarse grain they are capable of producing quality pork. Improved pig rearing could be made into a profitable subsidiary occupation for improving the economic lot of a number of backward communities such as Harijans, Balmikis, Sweepers, Dhammans, Voddars and Tribals.
There were 4.93 million pigs in 1956, 4.98 million in 1966 and 6.4 million in 1972. They form less than 1 per cent of the world’s pig population, producing about 50,000 tonnes of pork. Pig as a source of meat has not been properly exploited, for pigs are considered fit only to be reared on garbage and are allowed to remain as scavenging animals in villages and towns for their rearing has not been considered as a respectable farming occupation.
Hence, pig rearing has been relegated to the hands of socially backward and economically weaker sections of the people. Further, indigenous pigs are uneconomical for commercial exploitation because of their low growth rate, poor body weight, small litter size and late maturity.
Pig rearing can be developed as a subsidiary occupation by ensuring supply of good quality stock well-adapted to village conditions, breeding facilities, health cover, supply of supplemental feeds, improved management practices, training and extension, link up with marketing centres such as pork processing plants or urban slaughter house, organising of pig breeders cooperatives.
If pig rearing has to be profitable, replacement of indigenous types of pigs by cross-breeds or pure breed exotic animals like Middle White Yorkshire, Large White Yorkshire, Landrace is necessary. However, such cross-breeding would need an efficient system of feeding (such as cakes, chunis, bran, broken grains and by-products from slaughter houses and other balanced feeds) and management regimes such as early breeding, large litter size, mothering ability, rain or grain, feed conversion efficiency etc.
Under the piggery development programme, 8 modern large regional pig breeding farms-cum-bacon factories and pork processing plants have been set up at Harringhatta (West Bengal) Koothatukulam (Kerala), Borivilli (Maharashtra), Gannavaram (A.P), Alwar (Rajasthan), Aligarh and Ranchi. Around these bacon factories, piggery development has been stepped up through the supply of quality breeding stock arid health support and training of farmers in modern pig raising. In 1977-78, about 2,000 tonnes of pork and pork products were produced in these factories.
So far 52 pig farms and 174 piggery development blocks have been established. The regional breeding stations produce selected breeds of pigs for multiplication and distribution in piggery development blocks.
In the Fifth Plan, it is proposed to establish intensive piggery development projects around bacon factories and pork plants. 23 pig breeding farms would be set up. A new pig breeding station will also be set up for maintaining a genetic pool of high quality, imported stock.
Climate and Pig Production:
Pigs begin to suffer from the effects of overheating when the surrounding air temperature is more than 27°C; they begin to be affected by cold when the air temperature falls below 21°C. Therefore there is only a short temperature range of 6°C in which pigs feel comfortable although they can change their microclimate by huddling together in cold or spreading out in heat.
An important problem of the pig industry is that of preventing the overheating of pigs during summer heat waves. Although many farmers do not realise the dangers of overheating, it is usually not difficult to reduce the effects of high temperatures. Many of the methods now being used to keep poultry houses cool may also be used in pig pens. It is, of course, most important that pigs are never driven far during hot weather. An overheated pig may sometimes be saved by spraying with cold water, but it is best to avoid overheating altogether.
Overheating not only affects food intake and rate of growth, but it also affects fertility. When pigs feel too cold, they become much less efficient as converters of food. Some of the food they eat is used to keep their bodies warm. It is very important to make pig houses draught-proof, and steps should be taken to keep young pigs warm. Newly-born pigs require special care, for they are unable at first to control their body temperature properly.
Piglets which are allowed to become chilled feed less and are more sluggish than warmer piglets. Sluggish piglets may move too slowly to avoid the mother lying on them. Moreover chilled piglets may refuse to feed and may die in the first week of life. The use of infra-red heating lamps or heated floors in the farrowing pens has resulted in fewer losses of pigs in the first week of life.
Genetics of Pigs:
At one time it was common to divide pig breeds into two groups—the pork breeds like the Berkshire and the bacon breeds like the Tamworth and Large White. However modern methods of feeding and breeding have produced pigs which can produce either pork or bacon equally well.
There are six breeds used in the pig industry today, although it is dominated by the two white breeds—the Large White Yorkshire and the Danish Landrace.
The Large White breed was developed in Yorkshire in England. It is a big pig, all white in colour and is of the bacon type. It suffers from sunburn if kept out of doors. Although it is late developing, it grows quickly with good conditions and is very prolific. Litters of 15 piglets are common.
The Landrace was developed in Denmark by crossing the Large White with some Danish breeds. It is all white with ears that hang forward over the eyes. The Landrace is a bacon type pig with long sides and is noted for its milk production. It was first imported into Australia in 1957 but has now spread widely. It crosses well with other breeds.
The Wessex Saddleback is probably the third most popular breed in Australia. It is a black pig with a white saddle running from one foot up over the shoulder to the other foot. The ears droop over the eyes and can pick up seeds and burrs which may damage the eyes. The objectionable black skin colour can be eliminated by crossing it with one of the white breeds. It is a very popular breed in Queensland.
The Large Black or Devon pig is all black with ears that droop over the eyes. It is a large pig of the slower-growing bacon type which can be raised quite well on pasture alone. It is prolific and a heavy milker. An average litter size is fourteen. Objections to the breed include the dark skin colour and the fact that the sows are not very good mothers, often overlying the piglets. However, the breed crosses well with others.
The Berkshire is a black pig with six white points, having white on the face, the four feet and the tail tip. This breed was formerly regarded as a pork type, but the modern Australian Berkshire is the result of crossing pigs of the long-sided Canadian Berkshire, a bacon type pig, with pigs of the British Berkshire strain, a pork type pig.
The result is that these pigs are now longer, lighter in the shoulder and with less dished face than the original British Berkshire. The Berkshire has low fertility but crosses well with other breeds.
The Tamworth is the only red-haired pig breed in Australia. The Tamworth is a long legged pig of the bacon type. It is prolific and hardy and is useful in crossbreeding.
In commercial piggeries it is now a universal practice to employ crossbreeding.
This is done for two reasons:
1. Because the hybrid pigs resulting from the crosses show more vigour—hybrid vigour as it is called.
2. Because crossing breeds can produce pigs which are more versatile and can be raised as either porkers or baconers.
Progress in breeding superior strains of pigs will come when boars are tested for how well they can pass on good qualities to their progeny. Performance-tested hybrid boars are now being sold by some of the big producers.
Boar semen can now be frozen and it is possible that further progress in breeding will come when foreign semen is imported. Fear of introducing diseases has prevented wider use of imported semen.
Only in Queensland has a performance testing service been provided by the Government, but Victoria has a good advisory service for producers.
Nutrition Required for Pig Development:
High growth rates in pigs are only possible when they are given food of the right quality and quantity. Since the cost of feeding pigs is often 70 per cent of the total cost of raising them, it is important to avoid mistakes in feeding. Like other monogastric animals pigs need to be supplied with energy, protein, vitamins and minerals.
The commonest energy foods used for pigs are the grains. Barley is popular and has low fibre (six per cent) and protein content which varies from 10 to 12 per cent. Wheat is the second most popular grain feed with protein varying from about 9 to 13 per cent.
Maize is a high energy feed with a protein content of 9 to 10 per cent, but it is low in calcium content. Sorghum has 10 to 11 per cent protein and has low fibre but needs cracking before feeding. The best energy feed for pigs is that which is cheapest per unit of energy to buy, but the percentage of fibre must not be too high as pigs cannot digest cellulose.
The energy needs of pigs can be expressed in many ways. A common way is to use the meal unit system. A meal unit is that quantity of a feed which is equal in energy value to 0.45 kg of barley meal. The metric measures of energy are in terms of megajoules, but a minimum protein content is also specified.
The most important protein sources are meat meal (50 per cent protein), fish meal (67 per cent protein), soyabean meal (46 per cent protein) and cottonseed meal (44 per cent protein). The general rule about protein in pig diets is that the younger the pig, the higher the protein content required.
Thus the protein content of diets for suckers averages 18 to 19 per cent, that for growers 16 per cent and that for a breeders’ ration, 14 per cent protein. If wheat with a low protein content of 10 per cent is being fed, then a protein supplement must be added to the ration. On the other hand, if it is a high protein wheat (13 per cent) then it is only necessary to add a little of the amino acid lysine to the ration for breeders.
Commercial feed firms now supply growers with specially prepared pre-mixes which can be added to the ration. These pre-mixes may contain certain amino acids like lysine as well as all the needed vitamins and minerals.
If the pig has an adequate diet then it will convert a lot of its food into meat. The food conversion ratio (or FCR) is the ratio between the numbers of kilograms of food eaten to the number of kilograms of weight added. If the young pigs are raised efficiently they should have an FCR of 3:1, but from body weights of 40 to 70 kg, the FCR falls to 3.6:1. Larger pigs of 70 to 90 kg can only achieve an FCR of 4:1.
Table 46.3 shows how the food needs of pigs and their protein percentages vary with the body weight and age of the pigs:
Feed costs on some holdings of the extensive type can be reduced by providing pigs with good quality pastures. Roughages such as pasture provide satisfactory feed for dry and pregnant sows but not for fattening.
Diseases of Pigs:
Few ways of improving pig raising are as important as the reduction of diseases and parasites in herds. Besides the serious diseases, pigs are subject to a number of diseases similar in their effects on production to the disease CRD in poultry; that is, diseases which may not kill the pig, but which cause it to become “unthrifty” and a very inefficient converter of food into meat.
One of the great principles of disease control is that of isolation. Pigs catch many diseases directly from other pigs, or from visitors who may bring germs of disease into a piggery on their feet, hands or clothing. If a young animal is isolated from contact with visitors and from pigs of other farms, it cannot pick up diseases from them. This is why many large piggeries do not allow visitors to enter the houses where pigs are kept.
It is for these reasons that some pig producers are now breeding only from SPF pigs (specific-pathogen-free pigs) or MD pigs (minimum disease pigs), which are not born naturally. SPF pigs are produced by operating on a pregnant sow just before she is due to farrow. The sow is anaesthetised, the abdomen opened, and the complete uterus with foetuses is removed under sterile conditions.
Each foetus is removed in such a way that no contact with the outside of the mother’s body is allowed. The piglets are transferred to a heated sterile shelter and fed on special food which is a substitute for the mother’s colostrum and milk. Since they receive no Colostrum they are sometimes called “colostrum-free” pigs.
These pigs are then reared in complete isolation from all other pigs and normally they remain free of certain infectious diseases. This procedure need only be done once or twice (or the pigs bought from SPF breeders) and the farmer then has the beginning of a disease-free herd. These pigs can then breed and give birth to their young naturally. Such pigs use less food to make a kilogram of meat and the veterinary bills of the producer are reduced greatly.
This idea has largely dropped out of favour in the United Kingdom and Europe because it does not seem to be so successful in reducing disease, perhaps because piggeries there are so much closer together. However it is still a useful idea in Australia possibly because the greater distances between piggeries in our country allow the technique to be more successful, and because our harsh climate kills off the microbes causing disease. One of these diseases is erysipelas which is an acute or sub-acute disease which produces red patches on the skin and causes the pigs to go off their feed.
Virus pneumonia is one of a number of diseases affecting the respiratory system. There is no treatment for this disease which makes the pigs cough and causes them to be unthrifty.
Tuberculosis is not very common, but many carcases are condemned when they show signs of the disease.
Swine paratyphoid (or Salmonellosis) is common in Australia. In bad cases there is reddening of the skin and eventual death. Chronic cases do not die but the pigs are very unthrifty.
The worst of the internal parasites are the large round worm (Ascaris) and the kidney worm (Stephanurus). These pests can be controlled by applying well-known rules of hygiene, by understanding the life cycles of internal parasites, by employing new ideas for housing and by using drugs.
These pests are harder to control if pigs are kept outside, and mud wallows are responsible for spreading many parasites. One reason pigs like wallows is because this helps them to keep cool, but there are better ways of preventing overheating, such as providing shade.
Housing of Pigs:
Modern intensive piggeries employ large houses which make use of a number of modern ideas. It is common to find that a pen for a pig such as a boar or a pregnant sow consists of two areas. In one area the floor is slatted so that urine and faeces can fall through to the ground.
This reduces the spread of parasites because the pig is separated from its manure. Pigs soon learn to use these slatted areas for dunging, thus keeping the other area clean. This other area is commonly made of concrete and the modern tendency is to drop the food rations straight onto this concrete area and not to use troughs.
In houses of modern design various divisions of the house make it easy to move pigs in one direction as they move from one growth stage to another.
The size of the fattener area depends on the relative numbers of porkers to baconers raised.
Modern housing incorporates insulation as protection against high temperatures. The provision of warmth for newly-born pigs is achieved either by heated parts of floors or by the use of infra-red heating lamps. The effect of these heated areas is to attract piglets away from the sow so they are less subject to overlying.
Improvement in Pig Reproduction:
There is room for considerable improvement in pig reproduction. Thus the average sow only rears 11.4 pigs per year and the average Australian sow only has 1.7 litters per year. These figures should be compared with the performance of some of the most modern piggeries in Australia in which the average sow rears 18 to 19 pigs per year and has 2.2 litters per year.
Important new ideas for improving reproduction include the following:
1. Early weaning. Intensively housed pigs are now weaned at 3 weeks instead of the old idea of weaning at 8 weeks.
Two facts make this trend possible:
(a) The sow’s lactation curve reaches its maximum at three weeks, but the milk demand of the piglets is rising rapidly at this time.
(b) Three weeks is about the minimum interval after birth needed to make sure that the sow will have a good conception rate at her next mating.
2. Use of better farrowing pens. Although nearly 15 pigs are born alive to each sow per year, she only rears 11.4 of them. One of the main reasons for this situation is that the sow lies on some of the piglets and kills them. The use of farrowing crates is a modern idea which reduces piglet deaths from overlying.
The farrowing sow is put into a rectangular crate which is made of tubular steel rails. It is 60 cm wide and the lowest of the steel bars along the side is 20 cm from the floor. The sow cannot turn around in the crate, but when she lies down her legs and udders project from the crate. Heat is provided outside the crate so piglets are attracted away from the sow.
3. In an attempt to prevent sows from turning around and lying on their piglets, many producers tether the sows to one end of their pen, but this is not done if farrowing crates are used.
4. Much attention is now being paid to reducing the harmful effects of high temperatures on reproduction. This has become important as more holdings are located in the hotter grain areas rather than the traditional location in coastal dairying areas.
5. The use of foreign frozen boar semen is another possibility for improving the quality of pigs. Until recent years it was not possible to freeze boar semen, but this can now be done, although conception rates in sows may be low. Imports of foreign semen have stopped in recent years due to fear of introducing diseases, but it is possible that ways may be found of overcoming this problem.
Reducing Psychic Stress in Pigs:
High efficiency in producing pig meat is only possible when bullying is not allowed to become severe. Social orders occur in groups of both sexes, and when bullying increases some pigs may be excluded from feeding troughs. Low social order can therefore mean slow growth rate.
Bullying and psychic stress become obvious as soon as pigs are crowded in pens, or if lengths of feeding troughs are too short. Studies of behaviour in pigs provide strong arguments in favour of keeping pigs in age groups, and for not introducing single strangers into a well-established group. With careful planning of pens and facilities, and with careful control of density, psychic stress in pigs can be reduced to a small problem, but the only complete answer to this problem is individual pens.
Barriers to Progress in Pigs:
Progress in Australian pig raising is being prevented by such things as the following:
1. Insufficient progress in developing really superior strains of pigs. Performance testing of boars could be more widely practised.
2. Disease and parasite control could be greatly improved.
3. Too many losses occur among new born pigs.
4. Too many farms lack housing of any kind and general hygiene is poor on some holdings.
5. Too few sows have two or over two litters per year.
6. The average age at weaning is 7.3 weeks and there could be a reduction in this figure.
7. Feeding is often unsatisfactory.
8. Some houses are poorly designed and result in high labour needs, overcrowding or poor disease control.