Pigs are smart, sociable and inquisitive animals. Today’s pigs descend from wild boars that were domesticated approximately 10,000 years ago in various locations in Asia and then crossed with wild boars in Europe. A pig’s natural lifespan may be up to 20 years In commercial pork production, pigs can be slaughtered as young as 6 months.
The breeding animals in a pig herd include the boars (entire male pigs), gilts (female pigs that have not had a litter of piglets before) and sows (female pigs that have had a litter of piglets before).
Breeding herds may be housed in completely indoor, semi-outdoor (outdoor bred), or entirely outdoor systems (free-range). Most pigs in Australia are housed in conventional indoor systems. In indoor systems, boars are housed individually in pens, and gilts and sows are mostly housed in group pens. In semi-outdoor and outdoor systems, gilts and sows are kept in group paddocks, and boars may be kept separate in a paddock or with other gilt/sows.
The Australian pig industry has committed to voluntarily phasing out sow stalls in favour of group housing for pregnant sows. Around 80% of sows in Australia are now group housed during their pregnancy. Unlike in other countries, where sows can be confined to sow stalls for 4 weeks or more of their pregnancy which lasts around 116 days. Group sizes may vary from small groups (up to 10 sows) to large groups (100 or more sows).
Mating of pigs may occur via natural or artificial insemination. Boars are used for the collection of semen as well as to bring the female pig onto heat, to determine if the female pig is on heat, or to mate naturally when artificial insemination hasn’t been successful or isn’t used.
In conventional systems, artificial insemination usually occurs in a mating stall in which the gilt or sow may remain confined for the first 5 days after mating before being returned to group housing. In outdoor systems, gilts/sows are brought into larger mating pens for natural mating or artificially inseminated after which they are then released back into a pen or paddock.
Towards the end of pregnancy, sows in conventional farming systems are moved into farrowing crates to give birth.
The farrowing section of a piggery houses sows due to farrow (give birth) as well as sows with piglets up to the point of weaning (when they are removed from their mother). The farrowing crate separates the sow from her piglets but allows piglets access to the sow’s teats so that they can drink. A sow may be confined in a farrowing crate for up to 4 weeks. Whereas, in extensive outdoor systems, pregnant sows are moved to farrowing huts that are located in a smaller outdoor area or paddock. In a farrowing hut, the sow is not separated from her piglets and is able to build a nest prior to giving birth as bedding is often provided.
Both sow stalls and farrowing crates confine pigs so that they cannot turn around and can only take a short step forwards or backwards. When confined like this, pigs are unable to perform highly motivated behaviours such as nesting at farrowing or foraging. To read more about the animal welfare issues associated with sow stalls and farrowing crates click here.
In the first few days of life, piglets undergo several husbandry procedures such as teeth clipping, tail docking and ear notching. To read more about the animal welfare issues associated with these husbandry procedures click here.
Some piggeries that operate exclusively as breeder farms, only house breeding animals. Any progeny (piglets) born are removed from the piggery at, or just after, weaning and sent to farms where they grow out.
Pigs raised in Australia to produce meat may be reared under different housing systems, these include indoor, semi-outdoor (deep litter) or outdoor (free range) systems.
In conventional indoor systems, piglets after weaning are moved into group pens and moved between different sheds depending on the stage of production. Piglets in semi-outdoor systems are moved into large sheds/barns with bedding such as straw or rice hulls, that may also have access to an outdoor pen area. In outdoor free-range systems, piglets are kept outdoors in paddocks with access to shelter with bedding. To read more about some of the animal welfare issues associated with pig farming click here.
Weaned piglets are raised for 5-6 months after which they are transported to an abattoir for slaughter.
Upon arrival at the abattoir pigs are unloaded from trucks and placed in group pens where they are provided water. Just prior to slaughter, pigs are walked up a raceway individually or in small groups to be stunned (rendered unconscious). Pigs may be stunned using electrical stunning or carbon dioxide controlled atmosphere stunning systems. Once unconscious, pigs are bled out to ensure death before further processing.
The meat from these pigs is used in the production of fresh pork products as well as bacon and ham (although the vast majority of bacon, ham and other cured pork products in Australia are imported). When sows and boars reach the end of their productive breeding life, their meat may be used for cured pork products such as salami. Other pork products include offal, blood products for human use, and ears, snouts and trotters for pet food, and pig hair for brushes.