The nurse sow system ‒ A natural process of handling large litters: A review

Reproductive performance in pig production has gained genetic momentum resulting in large litters. Several strategies have been used to raise the number of piglets to address the challenge of a large litter size. This review provides a rationale for employing the nurse sow system as a biological way of handling large litters, exploring its step-by-step processes and its selected impacts. By exposing these steps, pig farmers will use the information to pinpoint their weak points in the chain and customize the procedures to meet their farm-specific goals for improved productivity. The nurse sow system helps to maximize pre-weaning survival by boosting the overall worth of low birth weight piglets. When piglets weaned per sow/year are used as a performance benchmark, nurse sows weaning double litters become economically advantageous. Extended time in lactation for nurse sows gives them an ample time for their uterus to involute before the next pregnancy. However, nurse sows lose their body reserves reflected in backfat thickness from high milk production. Prolonged confinement in lactation deteriorates the physical condition of nurse sows, resulting in leg ulcers and teat damage. Additionally, piglets are more distressed when taken away from their biological sow to a new sow.