Reducing litter size for replacement gilts and boars could possible increase reproductive performance, but the goal is different for gilts than for boars. Gilts are mainly culled for failure to reproduce, and is called involuntary culling. Sows have peak reproductive performance between parities 3 and 6, so reproductive improvement would involve improving reproductive success over a longer time span. Boars are culled after 12-18 months because a new generation is starting, and it is voluntary culling. So for boars, increasing reproductive performance over a short time span is the goal. Smaller litters may allow replacement piglets reduced competition and more nutrients, and as the sexual organs are still developing at this point it could positively influence later performance. The size of litter and day of boar exposure was tested for the effect on sow longevity, with the measure being which sows were still in the herd after their third parity. Smaller litters and earlier boar exposure (day 140) resulted in 26% more sows reaching their third parity, and a 10% increase in farrowing rate. Being raised in smaller litters also increased the number of pigs per litter by 0.5. The results show early management has a long-term reproductive effect on gilts and, although consistent boar exposure may not be possible, reducing litter size for replacement gilts is commercially feasible. Boars raised in small litters had a significantly reduced training period for semen collection than those raised in large litters, indicating increased libido. Small litter boars also had increased testicular size, numbers of spermatozoa, and appear to be more fertile from siring results from heterospermic insemination data. So, similar to gilts, litter size has an impact on a boar’s reproductive performance, and reducing the litter size through cross-fostering is a commercially feasible strategy.