Genetic Parameters for Feed Efficiency Indicator Traits in a Rotational Crossbreed Sow Population During Lactation Period

Vollständiger Abstract

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ABSTRACT The selection of feed efficient sows effectively converting feed into milk production and body weight gain will contribute to the overall profitability of pig farming systems. Consequently, the aim of the present study was to estimate genetic parameters for feed efficiency indicator traits during the sow lactation period, and to infer respective genetic and phenotypic relationships. Daily feed intake (FI), milk yield (MY), sow weight at farrowing (SWF), litter birth weight (LBW), sow weight at weaning (SWW) and litter weaning weight (LWW) were recorded between 2015 and 2024 on a total of 2418 lactating sows consisting of rotational crosses between German Landrace and German Edelschwein, kept in the University Giessen research herd. The dataset was used to predict different feed efficiency indicator traits including average daily feed intake (ADFI), residual feed intake (RFI), residual gain (RG), residual feed intake and weight gain (RIG), lactation efficiency (LE), feed conversion ratio (FCR) and metabolizable energy for maintenance (MEm). Growth indicator traits were average daily sow weight gain (ADG) and growth rate per litter (GR_L). (Co)variance components for feed efficiency indicator traits, growth indicators and MY were estimated by applying multiple‐trait repeatability animal models via Gibbs sampling. Posterior means for heritability estimates (± posterior SD) for feed efficiency indicators were mostly moderate, that is, 0.14 ± 0.02 for ADFI, 0.28 ± 0.04 for RG, 0.19 ± 0.03 for RIG, 0.14 ± 0.02 for RFI, 0.21 ± 0.04 for FCR, 0.11 ± 0.04 for LE and 0.27 ± 0.03 for MEm, accompanied with moderate additive‐genetic variation. Milk production and growth indicators displayed moderate posterior heritability estimates with 0.22 ± 0.03 for MY, 0.27 ± 0.02 for ADG and 0.13 ± 0.02 for GR_L. The posterior means of genetic correlations among feed efficiency indicator traits were consistent with their corresponding phenotypic correlations, displaying similar magnitudes and same signs. Largest genetic correlations were estimated between RG and RIG (0.85 ± 0.02) and between FCR and LE (0.96 ± 0.01). The strong genetic correlation between LE and ADG (0.70 ± 0.13) reflects the increased energy demand for milk production during lactation, also expressed in the genetically negative correlation between LE and GR_L (−0.57 ± 0.12). Correlations between MY and ADG were genetically (−0.71 ± 0.08) and phenotypically (−0.40 ± 0.11) negative. Genetic and phenotypic correlations between RFI and ADG close to zero suggest the integration of RFI into breeding indices without compromising growth traits.