When does a sow's litter size peak?

A sow's litter size typically peaks during the later part of her reproductive life, specifically around the fourth and fifth litters. This peak occurs because as sows age and experience more pregnancies, their reproductive efficiency improves, leading to larger litters. Factors contributing to this increased litter size include the sow's physical maturity, experience in breeding, and overall health and nutrition status, which tend to improve after the first few litters.

During the early litters, particularly the first one, sows may be less experienced and not produce as many piglets. Similarly, as sows reach their later years (after the fifth litter), there is a gradual decline in reproductive performance due to aging and possible health issues. Therefore, identifying litter 4-5 as the peak period aligns with the biological and reproductive patterns observed in swine production.