Abstract
The aim of the study was to estimate the genetic parameters for reproductive performance in native breed sows covered by genetic resource conservation programmes in Poland. The study used data on reproductive performance of 1,182 Złotnicka White sows, 1,648 Złotnicka Spotted sows and 1,180 Puławska sows. The following traits were analysed: age at first farrowing, number of piglets born alive, number of piglets at 21 days of age and farrowing interval. Covariance components and genetic parameters were estimated using an REML animal model with different combinations of fixed and random effects. Convergence of the iterative process was achieved by the selection of the AIREML algorithm. The estimated values of the coefficients of heritability for the number of piglets born ranged from h2 = 0.09 in the Puławska breed to h2 = 0.30 in the Złotnicka White breed. For the number of piglets reared, they varied between h2 = 0.09 in the Złotnicka Spotted breed to h2 = 0.27 in the Puławska breed. The heritability values for age at first farrowing and farrowing interval were higher, and ranged from 0.4 to 0.5. The significant positive and negative coefficients of phenotypic correlation, estimated between age at first farrowing and farrowing interval with the number of piglets born alive and reared per litter, suggest that the native pig breeds should be bred in keeping with their breed predispositions.