Pig farming is the raising and breeding of domestic pigs as livestock, and is a branch of animal husbandry. Pigs are farmed principally for food (e.g. pork, bacon, gammon) or sometimes skinned.
Breeds of pigs
The indigenous pig has been the basis used for pig production for a long period of time. It is small in size. Improved breeds are now being used for grading up the form the basis for pig production in the rural areas.
Imported pig breeds reared in India are as follows:
- Large white Yorkshire
- Middle white Yorkshire
Selection of breeding stock
Important characteristics which need to be considered in developing a good sow herd are:
- Size of litters
- Strength and vigour of litters
- Milking ability
Gain and feed efficiency, fertility, selection of individual animals from a herd is more important than the selection of a particular breed. Each producer at the time of setting up his herd should purchase his animals from a reliable disease free herd and should obtain as much information of the animals as possible. Once the herd is established the selection of the gilts and boars for replacement in the breeding herd should be based on the types and performance.
Selection of gilts (female)
- Selection of gilts for the breeding herd should be made at market weight ie. When the animals weigh about 90 kg
- Select gilts from sows which have consistently farrowed and weaned large litters
- They have reached market in minimum time and have desirable market type
- It would be desirable to choose gilts whose litter mates and other fullsibs have given good performance in daily weight gain and feed conversion efficiency.
Selection of boars (male)
- Selection of boar is extremely important, particularly for a small breeding farm or unit.
- The boar should be purchased from a breeder or a farm maintaining adequate information on its performance.
- The boar should be selected from a dam which has consistently farrowed and weaned high litters
- A good boar will weigh 90 kg in about 5-6 months will be of good type and will be strong on feet and legs
- The feed conversion from weaning to 90 kg weight would be the most desirable.
Age of breeding stock
Well developed gilts may as a general rule bred to farrow when 12-14 months old. This depends more on development than on age. Gilts should weigh at least 100 kg before breeding. Ovulation rate increases during successive oestrous periods (up to fifth) following puberty. Thus it is advantageous to delay the breeding of gilts until the second or third oestrous. Litter size increases on an average in succeeding pregnancies up to 5th or 6th litter. It is therefore advantageous to cull the sow from a breeding herd or a commercial herd after her fifth or sixth litter as the litter size goes down thereafter.
Detection of heat
The average length of oestrous cycle in pigs is 21 days. The oestrous symptoms last for five to seven days beginning with vulvar swelling and vaginal discharge. In true oestrous there is frequent urination, reduced appetite, mounting and standing for service detected by the erection of ears and immobility when normal pressure is applied to the back. The application of pressure on the back is used to determine the correct breeding time. Animals with a predisposition for weak oestrous should be brought near the boar to exhibit heat symptoms a little more clearly.
Best time for breeding is during the latter half of the first day or early on the second day of oestrous. In many cases the gilts and sows continue to exhibit the standing heat on the next day. In these cases the animals should be rebred and the interval in the case of rebreeding should be 12-14 hours. This procedure will ensure a high conception rate in the herd.
Care and management of pregnant animals
The gestation period of sow varies from 109-120 days with an average of 114 days. Pregnant animals should be housed in groups in separate enclosures and should not be mixed with new animals to avoid fighting which at times may result in abortion. It would also be advisable to house pregnant gilts and sows in separate groups during gestation. About 3 m2 of dry housing should be available for each sow. The pregnant animals should be allowed to move about every day in the morning on a free range or a pasture if available. A pasture area is presumed to be clean if a cultivated crop was raised.
Management at farrowing
Farrowing time is the critical time in pig production. Death rate is high during farrowing and the first week after farrowing. Sows may be farrowed in pens equipped with guard rails and a creep space in farrowing crates or in farrowing stalls. A pen equipped with guard rails and a creep space is adequate. The pen should be maintained at 24ºC to 28ºC until the piglets are three or four days old and at 18ºC to 22ºC until the piglets are approximately six weeks old. The heat lamps should be hung 45 cm from the floor and suitably protected. The farrowing pens should be thoroughly cleaned before the sow is brought in. This will prevent a large number of diseases of piglets. The sow should brought to the farrowing pen atleast one week prior to farrowing so that it becomes familiar with the surroundings. She should be washed thoroughly before being brought to the farrowing pen. The feed ration should be made bulky by substituting one-third of the regular ration with wheat bran. The amount of ration fed should also be reduced by one third till the sow farrows. The sow should be watched closely for determining the approximate time of farrowing and feed should not be given 12 hours before farrowing.
Prevention and control of pig diseases
- All pigs should be vaccinated against swine fever at the age of 2-4 weeks. Breeding pigs should be tested for brucellosis and leptospirosis. As a routine measure all young pigs at the time of weaning should be inoculated against swine fever.
- Animals purchased for the farm should be purchased from disease free herds. Newly purchased animals should be isolated from the other animals in the farm for a period of three to four weeks. No visitor allowed visiting the farm. Those stys or pig houses cleared of the animals are kept empty for three to four weeks for destruction of microorganisms causing the disease.