Effect of growth and compositional traits on first parity and lifetime reproductive performance in U.S. Landrace sows

The objective of the study was to determine the effects of growth and compositional traits on first parity and lifetime reproductive performance of purebred Landrace females. Females with reproductive performance and growth/compositional records were obtained from the National Swine Registry. Using the raw data, adjusted backfat (BF), loin muscle area (LMA), and days to 113.4 kg (DAYS) were calculated. Females were grouped into six categories based on the standard deviation of each adjusted growth and compositional trait. Information calculated from raw reproductive data included: first farrowing age, sow longevity, maximum number of parities (MPP), adjusted first parity number of pigs born alive, weaned, and 21-day litter weight, adjusted lifetime number of pigs born alive, weaned, and pounds of pigs weaned. Sows within the lowest BF group had fewer (P < 0.05) lifetime number of piglets born alive compared to sows in other BF groups. Sows in the fattest (> 2.49 cm) BF group had more (P < 0.05) LNBA than sows in the BF group IV (1.70-2.11 cm fat) and group V (2.12-2.49 cm fat). The fattest group averaged a greater maximum number of parities (P < 0.05) when compared to the other five backfat groups.