Heritability of Productive, Reproductive and Carcass Traits in Pure‐Bred and Cross‐Bred Pigs: A Systematic Review and Meta‐Analysis

Abstract

ABSTRACT Heritability ( h 2 ) is a key parameter in animal breeding, but its magnitude and consistency across pure‐bred (PB) and cross‐bred (CB) pig populations remain poorly understood. This study aimed to compare heritability estimates between PB and CB populations for economically relevant traits through a systematic review and meta‐analysis. A total of 28 studies (75 independent h 2 estimates) were identified through searches in PubMed, Mendeley, Springer, ScienceDirect and Google Scholar (2000–2024). Multilevel random‐effects models with logit transformation were applied. Traits were grouped into reproductive, growth, conformation and carcass categories. Reproductive traits showed low heritability (e.g., litter size: 0.06 in PB and 0.20 in CB; number born alive [NBA]: 0.07 in CB), whereas growth and carcass traits exhibited moderate values (e.g., average daily gain: 0.21 in PB and 0.31 in CB; intramuscular fat: 0.31 in PB and 0.29 in CB; pH: 0.23–0.26). Meta‐regression did not detect a significant effect of population type ( β = 0.124, p = 0.630), whereas studies accounting for non‐additive genetic effects showed significantly different heritability estimates (QM = 4.35, p = 0.037), and high heterogeneity was observed across traits ( I 2 > 90%). These results indicate that cross‐breeding does not systematically increase additive heritability. Instead, differences depend on trait type, likely reflecting differences in genetic architecture and the relative contribution of additive and non‐additive genetic effects. Overall, these findings highlight the importance of population‐specific genetic evaluations and context‐dependent breeding strategies in pig production, supporting the complementary interpretation of heritability and pure‐bred–cross‐bred genetic correlation (rPC) within Combined Cross‐bred and Pure‐bred Selection (CCPS) programmes.