Genetic relationship between litter size traits at birth and body measurement and production traits in purebred Duroc pigs

Heritabilities of litter size traits at birth (total number born (TNB), number born alive (NBA), and number still born (NSB)) and their genetic correlations with body measurement (body height, body length, front width (FW), chest width (CW), hind width, chest depth, chest girth, front cannon circumference, and rear cannon circumference) and production traits (ages at the start and end of performance testing (D30 and D105), average daily gain (ADG), backfat thickness, and loin muscle area) in purebred Duroc pigs were estimated. Records of performance testing for 2,835 animals and farrowing records of 1,168 litters from 437 dams were used. Genetic parameters were estimated using single-trait and two-trait animal models. Permanent environment effect was considered for litter size traits and common litter environmental effect was considered for body measurement and production traits. The estimated heritability was 0.10 ± 0.06 for TNB, 0.16 ± 0.06 for NBA, and 0.08 ± 0.05 for NSB. Positive genetic correlation of NBA was estimated with D30, D105, and ADG (0.51, 0.11, and 0.39). The estimated genetic correlation of NBA was 0.47 ± 0.17 with FW and 0.55 ± 0.18 with CW, implying that FW and CW could be promising indicator traits for efficiently improving NBA.