Disease & heat resistance

Genetic relationship between disease resilience and selection index traits

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Abstract

Diseases have a major impact on welfare, productivity, and profitability in pig production. Previous research conducted by our group showed that selection for enhanced disease resilience (via marker-based selection or genetic selection) can be used to mitigate morbidity and mortality under challenge. For global distribution of breeding stock, breeding companies nowadays have high health nucleus environments, which reduces incidence of challenge and omits the environment to assess the relation between disease resilience and productive performance of animals. As such, in the absence of diseases, the possible impact of selection for enhanced disease resilience on production traits is not well understood. Therefore, objectives of this study were to: 1) validate the effect of a known genetic marker for Porcine Reproductive and Respiratory Syndrome (PRRS) resilience under disease challenged conditions; and 2) estimate genetic correlations between disease resilience traits and production traits. Phenotypes collected within the first 28 days post-challenge on 10,576 crossbred and finishing animals were used to estimate breeding values for two disease resilience traits: health challenge mortality (HCM) and health challenge gain (HCG). Phenotypes were collected in six independent experimental PRRS virus infection trials where three strains were used in full confounding with individual trials, which was accounted for in the statistical model. Breeding values were estimated using univariate models, applying a crossbred genomic relationship matrix, including purebred ancestors. Breeding values for HCM and HCG were then correlated to breeding values for 106 other traits available from routine genomic evaluation. Assessment of the correlations included 14,906 relatives covering three generations. Results showed that genotype probabilities for a mutation within the GBP5 gene (previously associated with resilience to PRRS challenge) were favorably correlated with HCM (-0.14) and HCG (0.27). The average mortality rates were 10.1% for the homozygous and 10.7% for the heterozygous animals carrying the favorable A allele vs. 18.3% for animals with the unfavorable (CC) genotype. Further, slightly favorable correlations were found between breeding values for HCM and piglet vitality (-0.10), and HCG (-0.30). A slightly unfavorable correlation was found between HCM and total feed conversion (-0.12). For HCG a slightly unfavorable correlation with gestation length (0.12), and a slightly favorable correlation with sow longevity (0.12) was found. Standard errors on the estimates were all below 0.005. In conclusion, these results validate the effect of a genetic marker for disease resilience, where the favorable genotype was associated with lower mortality and greater growth under challenge. Therefore, a combination of marker-based selection (based on GBP5 SNP genotype), selection based on phenotypes defined as mortality and growth under challenge, and on related traits (piglet vitality, sow longevity) presents a promising opportunity to select pigs for enhanced resilience to disease challenge.

Keywords: 2026

How to Cite:

Dunkelberger, J., Sevillano, C., Vargovic, L. & Wijga, S., (2026) “Genetic relationship between disease resilience and selection index traits”, World Congress on Genetics Applied to Livestock Production Digital Archive 2026(1): 2286750. doi: https://doi.org/10.31274/wcgalp.24109

Rights: 1