Genome-wide association study for response to vaccination in Angus calves¹

Area of Science:

• Animal Genomics
• Veterinary Immunology
• Quantitative Genetics

Background:

• Bovine respiratory disease complex (BRDC) causes significant economic losses in the US beef cattle industry.
• Vaccination is a key strategy to reduce BRDC incidence, but morbidity and mortality persist.
• Identifying genetic factors influencing vaccination response is crucial for improving herd health.

Purpose of the Study:

• To identify genomic regions associated with variations in vaccination response in Angus cattle.
• To estimate heritability and prediction accuracy for vaccination response traits.
• To facilitate genomic selection for enhanced BRDC vaccination efficacy.

Main Methods:

• Genome-wide association studies (GWAS) were conducted on over 2000 Angus cattle.
• Traits analyzed included viral neutralization antibody levels against four key BRDC viruses (BVDV1, BVDV2, BRSV, BHV1).
• Statistical analyses focused on identifying 1-Mb genomic windows associated with genetic variance in response to vaccination.

Main Results:

• Six 1-Mb genomic windows were significantly associated with over 1% of the genetic variance for vaccination response traits.
• Heritability estimates for these traits ranged from 0.08 to 0.21.
• Prediction accuracy for selecting animals based on these markers varied from 0.01 to 0.33.

Conclusions:

• The identified genomic regions require further functional annotation due to a lack of clear candidate genes.
• Vaccination response traits are polygenic, with low to moderate heritability, suggesting potential for slow but achievable genetic selection.
• Genomic selection can be utilized to identify cattle genetically predisposed to respond better to vaccination, potentially reducing BRDC incidence.