Disease & heat resistance

Genetic parameters and genome-wide association studies of disease in growing pigs under a polymicrobial natural disease challenge

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Abstract

This study aimed to estimate genetic parameters and identify genomic regions and pathways associated with disease of growing pigs exposed to a natural polymicrobial disease challenge. The challenge was established by introducing sick pigs into a wean-finish facility and maintained by introducing a new batch of 60 or 75, ~40 day-old clinically healthy Yorkshire x Landrace barrows into the challenge nursery (cNur) every 3 weeks, with a 1-week overlap with the previous batch, before the latter was moved to the finisher (FIN). Data included individual health treatment(s) and mortality records on 4095 barrows from 7 breeding companies. Using generalized and linear mixed models with genomics, traits analyzed included treatment rates (TRR) and mortalities (MOR), categorized as meningitis (ME), respiratory distress (RD), scours (SC), unthriftiness (UNTH), and other (OT). Heritability estimates for TRR and MOR were generally higher in cNur versus FIN. RD tended to have higher heritability estimates than other diseases in both cNur (TRR-RD: 0.14±0.03, MOR-RD: 0.09±0.08) and FIN (TRR-RD: 0.07±0.03, MOR-RD: 0.18±0.09). Litter effects were generally low ( < 5%) but stronger in cNur. Genetic correlation estimates among RD TRR and MOR were generally positive, ranging from 0.23 ± 0.23 for FIN TRR with FIN MOR to 0.95±0.30 for cNur MOR with FIN TRR. Corresponding genetic correlation estimates for other diseases were either moderately negative (-0.19±0.32 for OT TRR in cNur versus FIN) or did not converge. Genome-wide association studies identified several genomic regions and candidate genes on chromosomes 7, 8, 13, and 18 for OT and RD TRR in cNur and FIN. Gene set enrichment and pathway analyses identified several enriched biological processes, including disease susceptibility and immune capacity. This study provides valuable information to breed for disease resilience. Funding from Genome Canada, Genome Alberta, Genome Prairie, PigGen Canada, USDA NIFA (2017-67007-26144), and the National Pork Board Survivability Project.

Keywords: 2026

How to Cite:

Kabuye, U., Harding, J., Dyck, M., Fortin, F., Plastow, G., PigGen Canada & Dekkers, J., (2026) “Genetic parameters and genome-wide association studies of disease in growing pigs under a polymicrobial natural disease challenge”, World Congress on Genetics Applied to Livestock Production Digital Archive 2026(1): 2283742. doi: https://doi.org/10.31274/wcgalp.23509

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