Sow farm revenue and production costs are typically calculated on a per weaned pig basis. This encourages a reduced lactation length and weaning age in order to increase the number of pigs weaned per week. Pig weaning age is declining due to the fact that lactating sows have a fixed amount of space and the fact that the number of litters farrowed per week is increasing. In this paper, researchers investigate the economic impact of lactation length on post-weaning performance. One of the main results obtained was that reducing sow inventory in order to increase lactation length led to little improvement in the systems profitability. This is due to the fact that the reduction in sow inventory ultimately results in a lower amount of pigs weaned, and although they are heavier and they do grow faster, it is not enough to make up for the lower amount of pigs marketed. Alternatively, increasing physical lactation spaces to increase lactation length will have a payback of less than two years in many production systems.