A mating stall is a crate used to hold a female pig for artificial insemination. A mating stall allows the female breeding pig to stand up or lie down but prevents her from turning around. In conventional indoor systems where pregnant pigs are group housed, sows (female breeding pigs that have had a litter of piglets) may be placed in a mating stall immediately after her piglets are weaned. The sow will come into heat within days of her piglets being weaned, then be artificially inseminated, and remain in the mating stall for up to five days. The sow is then released into a group housing environment with other pregnant sows.
Mating stalls provide sows with protection from aggressive encounters with other sows – which may occur when sows are mixed into groups after weaning or immediately after insemination. In recently inseminated sows, such aggression may lead to pregnancy loss. This is because aggression induces stress which can affect the hormones secreted at the time that the embryo is attaching to the uterine wall (called ‘implantation’) potentially resulting in pregnancy failure.
A mating stall effectively replaces the sow stall in which the sow was traditionally impregnated and then housed during her pregnancy.
A sow stall is a metal-barred crate that houses a single sow for all or part of her 16 week pregnancy. The floor of the stall is usually concrete, with a slat-covered trench for manure at the rear. A standard sow stall is just 2 metres long and 60 cm wide. This is just enough space for the sow to stand up in — she cannot turn around and can only take a short step forward or back. The Australian pig industry has committed to voluntarily phasing out sow stalls after the first five days of pregnancy in favour of group housing for gestating sows. Where sow stalls are still in place, regulation currently requires that they not be used for more than six weeks in any gestation (pregnancy) period.
The RSPCA Approved Farming Scheme standards allow the use of mating stalls only for the minimum time period required to carry out the artificial insemination procedure. Sow stalls are not permitted under the RSPCA Approved Farming Scheme.