Genome‐Wide Association Studies for 24 Hematological Traits in Production Pigs Before and After Weaning

Hematological traits are essential indicators of an animal's immune status and overall health, reflecting both physiological and pathological conditions. The complete blood count (CBC), a commonly used clinical test, evaluates the concentrations, proportions, and characteristics of various blood cell parameters, providing insights into an animal's current health status. CBC phenotypes are dynamic, influenced not only by health status but also by factors such as physiology, nutrition, environmental conditions, age, and genetic makeup. Previous studies have estimated heritability for specific blood parameters and genome-wide association studies have identified loci associated with CBC phenotypes. While some loci seem to have similar effects across age and breeds and even across species, other loci seem to have a more breed and/or age-specific effect. This study extends previous research by conducting genome-wide association studies (GWAS) of 24 hematological traits measured in the same pig cohort at two ages (25 and 46 days). The GWAS included 1884 pigs at 25 days and 1615 pigs at 46 days, with 1499 pigs sampled at both time points. This analysis identified 57 QTLs for complete blood count (CBC) traits, including 11 lead SNPs associated with more than one trait. All animals were (Landrace × Yorkshire) × Duroc crossbred pigs. Thirty QTLs overlapped with previously reported CBC QTLs in different pig breeds, providing further evidence for shared regulatory regions for CBC traits across pig breeds. Genes in 29 QTLs were associated with comparable CBC phenotypes in humans.