Genetic parameters for litter and carcass traits in Landrace and Yorkshire pigs

Abstract

Swine production has focused on improving litter size and carcass traits to enhance productivity. Genetic progress in traits such as the number of piglets born alive (NBA), birth weight (BW), number of piglets weaned (NPW), total teat number (TN), number of days to reach 100 kg (AGE100), backfat thickness (BF), and loin depth (LD) is of great importance for breeding efficiency. The present study aimed to estimate genetic parameters, including heritability and genetic correlations, for the mentioned traits in Landrace and Yorkshire pigs. Genetic parameters were estimated using the restricted maximum likelihood method, considering an animal model. Heritability estimates ranged from 0.06 (NPW) to 0.41 (BW) in Landrace and 0.04 (NPW) to 0.40 (BW) in Yorkshire. Maternal heritability and permanent environmental effects were low, with values between 0.02 and 0.05. The maternal permanent environmental variance ranged between 0.03 and 0.09. Repeatability estimates for all traits ranged from 0.10 (NPW) to 0.49 (BW). All the traits studied showed sufficient additive genetic variability, enabling effective selection in Landrace and Yorkshire pigs. Greater relative responses are expected for BF, BW, NBA, LD, and TN. Selection for BW may yield favorable correlated responses with NPW, TN, and AGE100, while direct selection for TN may enhance sow reproductive performance. Genetic correlations between BF and LD indicated that both traits can be improved simultaneously without unfavorable effects. Although the correlation between NBA and BW was not high, caution is warranted regarding the increase in litter size due to potential negative consequences, such as reduced birth weight and higher piglet mortality. Despite previous investigations on these traits, this study provides updated and robust estimates from a large, consistent, and environmentally controlled population, representing a valuable case study for commercial swine breeding programs.