A mating stall is an enclosure in which a sow is kept for the purposes of mating.
After weaning, sows will typically come back “on heat” within a few days. Only a sow “on-heat” can be successfully mated.
There are lots of behavioural signs that indicate that a sow is ready to be mated or “on heat”. The best sign is the “standing response”. Aptly named, the sow will just stand there firmly when a small amount of pressure is applied to her back and will not move. This is the most reliable indicator of heat onset and duration. The standing response is best induced by boar pheromones (found in boar saliva and urine).
Mating stalls allows access for the boar while protecting to the sow. Sows can see and smell the boar, but are safe from potential injury caused by the strong, aggressive male pig. Artificial insemination is also a common practice.
It is important that sows are able to be kept in the mating stall for up to five days after they are mated for two reasons:
- Aggressive sows. Keeping the sow away from other potentially aggressive sows protects her during the early stages of fertilisation and embryo development, increasing the chance of a successful pregnancy.
- Mixing into groups. It allows the sows to be mixed back into their groups all at the same time, when the entire group has come off heat. This “early mixing” strategy is vital for group housing. If sows are still on heat when they are mixed, they can get quite aggressive to sows that are no longer on heat. This becomes a welfare issue. Therefore, Australian farms that have stopped using sow stalls for the bulk of gestation may use mating stalls for a short period of time in order to protect the welfare of their sows in the very early stages of pregnancy.