Pigs are any of several mammals in the family Suidae of the order Artiodactyla, the even-toed hoofed mammals. Pigs have four toes, but only two bear the weight of the animal. They are omnivorous, with a simple stomach, and do not chew the cud. Another name for pigs is swine. In the USA, pig is only used for smaller swine, and those over about 150 kg are called hogs. A male pig is called a boar and the female a sow or also, when young, a gilt.
The domestic pig is probably a descendant of the wild boar, Sus scrofa. Wild pigs that exist today include the babirusa, bushpig, warthog, and wild pig. Domestic pigs have been bred for centuries. The foundation of the National Pig Breeders Association in Britain in 1884 and individual breed societies at subsequent dates have done much to establish the value of the pedigree pig trade as a national asset. With breeding and selection, the long snout, narrow head and agile, humped-back muscular body of the wild races have given way to a finer head and neck and a long, level, broad back giving better bacon, and stout hind limbs, making better hams.
The Large White, also referred to as the Large White Yorkshire, has a great reputation at home and abroad as a bacon pig and its cross with the Danish Landrace now largely dominates the European market. The head is short, the shoulders are fine and the long lean body is supported behind by well-rounded stout hams. The sows are docile and prolific and good mothers. This breed and its crosses provide the best bacon pigs. Its growth is rapid and its food conversion ratio (kg meat put on per kg of food) is good.
The Middle White was also evolved in Yorkshire, from a cross between the Large White and the Small White, the latter being now extinct. The Middle White is an excellent pork pig, attaining killing weight early, with a high percentage of meat to bone, and modern types are good for pork or bacon.
The Large Black is a breed long popular in Devonshire, Cornwall, Suffolk, and Essex. Although the Breed Society only came into being in 1899, the breed was recognized as pure for many years before.
The Tamworth originated in Staffordshire, and is characterized by its abundant, golden-red hair. It is supreme as a forager, producing a very high proportion of lean meat, and is esteemed for bacon crosses. The sows are less prolific than those of other breeds, but rear more of their offspring to weaning.
The Berkshire was the first British breed to be improved, records going back to 1850. The breed provides a very fine pork pig, and is considered valuable for crossing with larger and slower maturing breeds for bacon production.
The Wessex Saddleback, originating in Dorset, was formerly esteemed all over the country as a very hardy breed, prolific, of good mothering ability, and suitable for outdoor production. Its outstanding characteristic is the coloring, black head and neck; black body, hind quarters, and hind legs; with a white 'saddle' over the shoulders and forelegs joining a continuous belt of white hair.
The Essex, or Essex Saddleback, resembles the Wessex Saddleback with its belt of white encircling the shoulder and forelegs on a black body, neck, and head. The breed is esteemed for its hardiness, adaptability to outdoor conditions, and production of good pork and bacon, especially when it is crossed with the Large White.
The Gloucestershire Old Spot is an old breed originating at about the same time as and from similar parentage to the Berkshire, although the herd book only goes back to 1913. It is characterized by its white ground color with a few large black spots. The Welsh, although an old breed, has only become widely known since 1918. Its characteristics are said to resemble those of the Danish Landrace. It is a good bacon pig, though slow in growing.
Pigs are usually kept with three objectives: as a herd to provide gilts (females which have not littered) and sows for breeding; as a herd to provide piglets for the farmer or others to rear for pork or bacon; as a herd of bought-in pigs of a young age for growing to pork or bacon.
There is a wide variety of systems and that chosen will depend on considerations such as the objective to be gained, available labour, and type of housing available. Food may be fed dry as meal or pellets, in hoppers or on the floor; dry with water poured over it at the last moment or with separate drinkers; or pre-mixed wet and pumped into troughs. The ideal is to promote unchecked growth and a steady gain in weight from birth. As food comprises about 75 per cent of the total cost of production, careful thought should be given to the choice and balance of the rations. A balanced meal provides a proper proportion of protein for tissue-building, to carbohydrates (starches, fats and oils) for body heat, energy, and weight gains in body fat. This proportion, known as the nutritive ratio, is 1 : 4 to 1 : 5 for young growing pigs and breeding sows, and 1 : 6 to 1 : 8 for fattening pigs. The food must contain all the necessary minerals and vitamins and fresh water should always be available. The chief protein-rich foods are fish meal, meat meal, bean and pea meal, dried blood, dried yeast, soya-bean meal, decorticated ground-nut meal, and separated milk. The chief carbohydrate-rich foods are barley meal, flaked maize, maize meal, maize germ meal, wholewheat meal, tapioca meal, potatoes, bran, middlings, ground oats, brewers' grains, and sugar-beet pulp. The last five are considered somewhat inferior, owing to high fibre content, and should not bulk too largely in the rations.
Complete, balanced rations made up for all purposes are now widely used, but, as an alternative, producers can use their home-grown cereals to which should be added the right proportion of purchased 'concentrate' (protein-vitamin-mineral mix). Growth-promoters such as copper and certain antibiotic mixes are widely used in growing rations. Roots and green foods may supplement a reduced meal ration. Swill, consisting of hotel, restaurant, and factory waste is still an important food but must be balanced up by adding meal mixtures. Swill from whatever source must be boiled for at least one hour. It is most suitable for pigs of 25 kg and over. If the swill is not thoroughly boiled, there is danger of pigs catching infections from it which may be passed on in their meat. This is particularly true for trichinosis, infestation by a worm that is parasitic in pigs and people.
Pigs are naturally clean animals. Given good housing they will not soil their bedding, but usually void in a corner of their shelter or run. Dry, weatherproof quarters, free from damp and draughts, are essential for thrifty growth and good health. All the processes of pig production can be carried out indoors (intensive system) and there is a great variety in the design of buildings for such purposes. There is a wide choice of materials from treated wood to breeze and concrete blocks, but whatever the design the guiding principle should be that of comfort. Houses should be insulated to maintain an equable temperature and a tolerable atmosphere in terms of ammonia and moisture. Ventilation can be automatic or controlled by hand-switched electric fans and ventilators. Floors should either be electrically heated or laid down with insulating layers of material (brick, rubble, bottles, felting). For breeding, gilts and sows can be reared in groups or in pens or stalls, and when pregnant put into separate pens when due to farrow. Piglets to four weeks of age need a higher temperature than the sow which can be provided by hanging a heater above them in a 'creep' or box-like structure along the side of the tethered sow. Restriction prevents losses from crushing. Weaning at five weeks is becoming standard. Litters may be mixed in a weaner 'pool'/and after several weeks divided into batches for growing on to pork or bacon. Houses for the latter comprise rows of pens separated from each other with a central feeding passage, or grouped together with an overhead catwalk from which food is delivered on to the floor as required. Outdoor pig keeping (extensive system) where sows and their litters are housed in huts dispersed over the field, suits the Large White X Landrace cross, is low in capital investment and labour, and improves poor land. Although outdoor conditions may be rigorous, health records are good. Sectional wooden huts on runners or wheels or triangular pig arks are suitable for tethered sows with litters and weaner pigs. Feeding troughs are separate. Such buildings can be made into fold units by fencing runs, but need moving frequently. True fold units, consisting of a house with a run and a built-in feeder and water trough, are made of wood and constructed to be moved at intervals of not more than three days. They are suitable for boars, expectant sows, sows and litters, and smaller weaned pigs.
Every ounce of the pig is used, helping create an astonishing 185 products. Here are some of the more surprising uses for the animal...
1) Chemical weapons testing: Because of the pig's similarity to human tissue.
2) Ice cream: Gelatine regulates the sugar crystallization and slows down the melting process.
3) Fertiliser: Made from processed pig hair.
4) Low fat butter: Gelatine used for texture.
5) Beer: Gelatine used as a clarifying agent. Reacts with bitter substances and tannins to absorb cloudy elements, leaving clear drinks.
6) Fabric softener: Fatty acides from bone fat give color.
7) Paint brush: Made from pig hair.
8) Fruit juice: Gelatine absorbs cloudy elements to give clear drinks.
9) Shampoo: Fatty acids from bone far are used to give them a peark-like appearance.
10) Candle: Fatty acids from bone fat are used to stiffen the wax and raise the candle's melting point.
11) Bread: Protein from pig hair is used to soften dough.
12) Bullet: Bone gelatine used to help transport the gunpowder or cordite into the casing.
13) Medicine tablets: Gelatine is used in the shell to give it hardness.
14) Washing powder: Fatty acids from bone fat harden the substance.
15) Paint: Fatty acids from bone fat increase gloss.
16) Tambourine: Made on the pigs bladder.
17) Wine: Gelatine absorbs cloudy elements to give clear drinks.
18) Paper: Bone gelatine is used to improve stiffness and reduce moisture.
19) Heparin: Used to stop the formation of blood clots, it is taken from the music in the intestines.
20) Soap: Fatty acids from bone fat act as a hardening agent and give color.
21) Corks: Bone gelatine is used as a binder.
22) Insulin: Taken from the pancreas, as closest to human in chemical structure.
23) Yoghurt: Pig bone calcium is used in some yoghurts.
24) Cigarettes: Haemaglobin from the blood used in cigarette filters to create an artificial lung that supposedly lessens harmful chemicals reaching the smoker.
25) Photographic film: Bone gelatine acts as a bonding agent on the film sheet.
26) Dog food treat: Haemaglobin used as a red coloring agent.
27) Photodynamic therapy: Haemaglobin used in drug to treat retina decay in the eye. Drug is activated by shining laser into eye.
28) Moisturizers: Fatty acids from bone fat used.
29) Dog snack: Deep fried pigs nose.
30) Crayons: Fatty acids are used as a hardening agent.
31) Shoes: Bone glue is used to improve the texture and quality of the leather.
32) Train brakes: Bone ash used in production.
33) Toothpaste: Glycerine from bone fat is used to give toothpaste texture.
34) Hide glue: A strong glue used in the woodworking industry derived from collagen.
35) Face mask: With collagen to help reduce wrinkles and lines.
36) Alternative energy: Waste products used as fuel to produce electricity.
37) Energy bar: Treated collagen is a cheap source of protein for bodybuilders.
38) Cream cheese: Gelatine used to make it stable.
39) Whipped cream: Gelatine gives texture.
40) Sweets: Porcine gelatine used as a binding and gelling agent and to ensure the right texture is found in the following: liquorice, wine gums, chewing gum.
Economics of Pig-keeping
An economical unit comprises 30 sows and their progeny and two boars. It can be managed by one trained person and an apprentice. A herd of half pregnant gilts and half younger gilts, with some pedigree stock for future breeding, gives a sound beginning. The minimum housing would be about 16 farrowing sties, a feeding house for weaned pigs, and houses for the boars and growing gilts. Initial capital costs are high. Food comprises about 75 per cent of the production costs, and labour about 15 per cent, leaving about 10 per cent to cover sundries.