Analysis of Genetic Parameters of Carcass Traits and Daily Gain of Native Breed Pigs Raised in Poland

The aim of the study was to determine genetic parameters of live performance traits in pigs of three native breeds maintained in Poland. As part of the conservation programmes, the Puławska (Puł), Złotnicka White (ZW) and Złotnicka Spotted (ZS) breeds are monitored for productivity based on performance test results of these breeds. The study included 6042 gilts and 2406 boars of the Puławska breed, 866 Złotnicka White gilts, and 903 Złotnicka Spotted gilts. The genetic parameters were estimated separately for each breed, and also separately for sexes in the case of the Puławska breed. The components (co)variance and genetic parameters were estimated using the REML method for the animal model taking into account different combination of fixed and random effects. Convergence of the iterative process was achieved by the selection of AIREML algorithm. The coefficients of genetic and phenotypic correlations between measurements of slaughter traits and daily gain were low for all breed groups. In turn, the relationships between backfat thickness measurements and carcass meat percentage were estimated as high. Only the correlations of slaughter traits with loin eye height were not uniform for the analysed breed groups. The coefficients of heritability (h²) were high and intermediate for all breeds and sexes. The highest heritability coefficients were obtained for daily gain (0.58 in ZW to 0.80 in Puł gilts), followed by backfat thickness (0.37 in Puł gilts to 0.64 in ZW) and carcass meat percentage (0.40 in ZS to 0.56 in ZW). The lowest coefficients were obtained for loin eye height (0.24 in Puł boars to 0.40 in ZW). The estimated genetic parameters could be used to verify selection indices of the breeds included in the genetic resources conservation programmes.