Longevity of the breeding female has both economic and animal welfare implications for the swine industry. High culling levels lead to increased replacement rates and reduce lifetime productivity for individual breeding females and the breeding herd. Greater replacement rates increase production costs related to purchase (or development), isolation, and acclimation of replacement females. PigCHAMP [1-5] summaries (Table 1) from 1998 through 2003, report annualized replacement rates of \u3e 50% and average herd parity of only 2.5 litters. Breeding herd productivity and economic sustainability are compromised when females are culled early in life and prior to achieving a positive return on investment. Breeding program design and genetic selection decisions clearly influence sow longevity and establish the base for a profitable, sustainable breeding herd
