Pig breeding and farming

There are a variety of production systems that are used in industry today. There is no one ideal system in which the facility alone can meet all of the needs of the animal. The single most important factor in addressing the welfare of animals is the husbandry skills of the producer.

In an intensive system, pigs are usually housed through their growth and reproductive stages indoors in specialised sheds. A shed housing pregnant sows is called a dry sow shed. Sometimes, dry sows may be kept outdoors, but this is only possible in a limited number of situations where the climate is mild and soils are free draining. When she is ready to give birth to her piglets, the pregnant sow is then moved to a special birthing or "farrowing" area. Weaner pigs (weaned piglets) are kept in a weaning shed and finisher pigs are housed in a finishing shed. Most Australian pig farmers raise their pigs through the whole process in "farrow to finish" operations.

The high health status of Australian farms means that access of people and animals on to pig farms must be restricted to ensure that animals are kept healthy. These restrictions are known as "biosecurity" precautions.

Gestation
Young female pigs are called gilts. A gilt is usually eight months old before she is mature enough for breeding. They are normally housed in groups of three to 25 pigs per pen in the breeding area. Gilts are called sows once they are mated. Male pigs, or boars used for breeding, are penned individually, so they don't fight with each other. Pigs are very social animals and sows are kept either in groups or individually in close contact with their neighbours. They do have a strong social hierarchy and sometimes fight amongst themselves to establish who is dominant or subordinate in a group situation.

When gilts or sows enter oestrus in their reproductive cycles (about 21 days long) they are ready to be bred. Farmers oversee breeding to ensure the sow is receptive and successfully bred.

Increasingly, producers are using artificial insemination (A.I.), which is gentle on the sows, eliminates disease risk and can produce excellent pregnancy results. Larger farms may rely exclusively on A.I. in their breeding programs.

Piggery managers keep records of sow and boar performance in a book or computer program. Pregnancy tests are conducted by ultrasound and, if found negative, sows return to the breeding area. The ability to pregnancy-test greatly increases farm productivity.

Pregnant sows are called "dry sows" or "gestating sows" (non-lactating), and some are moved to individualised stalls after breeding. Individual dry sow stalls assist in reducing stress to the sow during the early critical stages of pregnancy. In stalls, sows can easily be examined individually for health and treated if necessary. Sows are fed individually and offered water regularly. They can lie down comfortably, stand up or sit and walk a few steps forward and back. The stalls are cleaned daily.

Sows in stalls may stay in them for a number of weeks, or the whole pregnancy. Farmers take care to minimise sow stress and to protect their sows from being jostled or injured by their herd mates during the first 30 days of pregnancy because of high risk of miscarriage. The length of the sow's pregnancy is 3 months, 3 weeks and 3 days, or 115 days. Sows will usually have two litters of piglets each year.

Farrowing
Sows are moved in groups to farrowing sheds approximately one week prior to giving birth. A farrowing stall allows the sow about the same movements as a gestation stall, but provides 'creep' areas along either side for the piglets. Adjustable rails alongside the sow slow her movement when she lays down, thus protecting piglets from being crushed.

Once the sow begins to farrow, the whole litter is born within 2 to 3 hours. The farmer keeps a close record of when piglets are born. Very shortly after birth, piglets will nurse. A heat lamp or pad and a warm farrowing room temperature ensures piglet comfort.

Piglets
Piglets are moved from the farrowing rooms at a weaning age which can be anywhere from 21 to 28 days depending on the producer's system. The weaned piglets or weaners are housed in nursery pens. Farmers continue to provide very warm temperatures for the pigs. Weanlings are sorted by size or by sex and size and provided with fresh water and feed at all times. They will remain in nursery pens until they are between 5 to 10 weeks old. They will then be moved to a grower area.

Growers / finishers
Weaned and growing pigs are group-housed in well ventilated sheds. Pigs instinctively select clean and dry areas for sleeping, resting and feeding. Pigs are very clean animals and choose to defecate in an area separate to their feeding area.

Transport
When pigs are market weight from 60kg to 110kg - they are loaded onto well-ventilated trucks for transport to market. The number of pigs in the load is carefully calculated taking into consideration truck size, travel distance, temperature and pig comfort factors. Transportation of pigs follows the Model Code of Practice for the Welfare of Animals - Land Transport of Pigs.