Sorry Trin, 'parity' is the term used in the pig industry for the number of litters a sow has produced (short version of parturition). Typically, a sow has her first litter at a year old, depending on your weaning age, she produces 2.2 or 2.4 litters per year. On average commercial sows are culled after 6 parities (litters) so would be about 3.5 to 4 years old.
She must raise at least ten to weaning age with feed costs as high as they are, once her number born alive drops below 12, or if she loses too many, and weans less than 10, she becomes uneconomical, and must be culled. Oversized sows will usually crush too many piglets and need to be culled,and sows that begin to drop off milk production are also culled. Some sows,if kept at a good weight, can produce up to ten litters about 5.5 years, these exeptional sows represent less than 10% of an average commercial herd. Any drop in production,survival or weaning weight in a mature sow (after 3 litters) should be reason to cull, they are just too expensive to feed if they are not performing!
Feel free to P.M. me if I can help futher.
Regards,Andy.
