Commonly asked questions about pig farming are answered here by an expert.
- The pigs used by farmers today have descended from the wild pig (Sus scrofa).
- The gestation period of the sow is about 116 days (3 months, 3 weeks and 3 days) and a litter usually consists of 8 to 10 piglets.
- The piglets are weaned at 35 days (or in modern piggeries as early as at 21 days).
- The sow comes on heat about 4 to 6 days after weaning and should then be served by a boar at least twice in a 12 to 24-hour period for effective reproduction.
- If the sow has not conceived during that time, she should be served again after 21 days. Oestrus is promoted by bringing her into contact with the boar.
- Young sows are usually first served when they’re 7 to 8 months’ old (about 100 kg and at the time of the second oestrus cycle).
- Boars are also used for the first time at this age.
- 1 boar is used to serve 12 sows and it is important that the boar should be fertile and skilled at mating.
The nutritional needs of pigs vary with age. The table below provides a general guide to the quantity and quality of feed required during different phases.
Pigs are omnivorous and their diet may include grain (e.g. maize, wheat, barley, and triticale), grain by-products such as bran and protein such as soybean oilcake meal, sunflower oilcake meal, canola meal, fishmeal, milk products, sweet lupines, beans or peas, as well as a mineral and vitamin premix.
The diets that are used in commercial units, and which give good results, have grains, bran and protein such as fishmeal and soybean oilcake as some of their main ingredients. For effective production, pigs must have a balanced diet with enough energy and protein (amino acids).
Sufficient clean drinking water must be available at all times. Lactating sows, in particular, need large quantities of water.
- In normal conditions a sow can raise 2.2 litters a year – about 20 piglets in total.
- If each attains a mass of 90 kg, a sow therefore produces 1 800 kg live mass or 1 400 kg of meat a year.
- Feed intake per sow is about 1.2 tons a year and each piglet would need about 270 kg of feed to reach 90 kg.
- Breeding sows are selected at 5 to 6 months of age or at 100 kg live mass.
- A sow should have six well-formed, well-placed teats on either side of the body.
- Their legs must be straight.
- A long body and well-formed trotters are important.
- A quarter of the sows and half the boars in a herd should be replaced every year.
- A sow is usually sold after she has produced 6 to 8 litters.
- Unproductive sows are usually culled earlier.
- 50% of the mortalities in pigs occur before weaning, especially during the first 2 days after birth.
- It is important to design the farrowing pen so the sow cannot lie on top of the piglets.
- The farrowing pen must be properly disinfected before the sow is placed inside (1 week before birth).
The piglets must then receive special attention:
- The tips of the teeth must be clipped at about 3 days.
Iron injections can also be given (for pigs in intensive production units).
Diarrhoea is one of the main causes of production losses in young piglets. Prevent this by providing clean, disinfected farrowing pens and straw. In cases of severe diarrhoea medication must be given. Be on the lookout for mastitis and milk problems in the case of sows.
A complete vaccination programme must be followed to treat diseases such as mange, E. coli which causes diarrhoea in piglets, leptospirosis, diamond skin disease and parvo virus. Sows should be dosed against internal parasites 3 to 4 weeks before farrowing.
- This article was written by Prof. Tertius Brand and first appeared in Farming SA.