Litters with a low birth weight phenotype present have decreased growth, increased mortality, and more variation in market weight pigs. A statistical analysis of 8,000 parity records at a facility found that if sows have low birth weight litters up to parity 3, then they will likely continue to do so. As well, sows with high birth weight litters up to parity 3 will likely continue to do so in later parities. This information is useful when deciding when to cull sows, and when managing sows (ie expected low birth weight sows could be put into the same farrowing room).