Genetic parameters and genetic gain for the reproduction traits in Latvian Landrace and Yorkshire sows populations

摘要

The aim of this study was to estimate genetic parameters for the reproduction traits of Landrace and Yorkshire sows and to analyze the genetic gain in these Latvian swine populations. Records of 14 577 first-parity and 27 359 later-parities Landrace sows and 6039 first-parity and 12 360 later-parities Yorkshire sows born between 2000 and 2012 were included in the analysis. The number of piglets born alive and 21-day litter weight at first and later parities, and weaning-conception interval between the first and second parity were included in the study. The genetic parameters were estimated using a single-trait animal model for the first parity and a single-trait repeatability animal model for later parities using REML procedure. Compared to heritability estimates for number born alive, heritabilities for litter weight were higher in both populations: in the first parity 0.10±0.015 vs. 0.31±0.021 for Landrace, and 0.05±0.016 vs. 0.23±0.028 for Yorkshire; in later parities 0.10±0.010 vs. 0.23±0.013 for Landrace, and 0.10±0.017 vs. 0.20±0.022 for Yorkshire. The heritability of reproduction traits was low; however, during the last ten years, reproduction traits in nucleus herds were improving. The results show that genetic progress in the last five years has been relatively low.