Beef cattle

Genomic analysis of weight gain in crossbred dairy calves

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Abstract

Crossbreeding dairy calves has become a practical approach to enhance growth and feed efficiency for non-replacement dairy calves. Despite its rapid adoption, limited information is available regarding the genetic basis of growth of crossbred dairy calves raised under commercial management conditions. Therefore, the objective of this study was to assess the genetic architecture of average daily gain (ADG) in crossbred Angus-Holstein calves during the pre (ADGpre) and post (ADGpost) weaning periods, and full (ADGfull) period, using genome-wide association analyses and functional annotation of the significant genomic regions. A total of 5,934 genotyped crossbred calves that arrived at a calf raiser between July 2023 and January 2025 were weighed at arrival, seven, and thirteen weeks of age to calculate ADGpre, ADGpost and ADGfull. Genotyping was performed using the Illumina Bovine 100K SNP panel and quality control removed SNPs and calves with call rates under 95%, and SNPs with minor allele frequency under 5%. After quality control, 82,213 markers were available for the genome wide association study (GWAS) carried in the GCTA software. The ADG phenotypes were adjusted for fixed effects that included presence of treatment for diseases over the interval of the thirteen weeks, sex of the calf, and season of measurement. Random effects of farm of origin and purchase lot were included to account for environmental and origin-related variability. The phenotypes adjusted for fixed and random environmental effects were used as the phenotypes for the GWAS analyses. Estimated heritabilities were 0.12±0.02 for ADGpre, 0.10±0.02 for ADGpost, and 0.21±0.04 for ADGfull, highlighting the high impact of environmental factors on early ADG. Genome-wide association analyses identified significant SNPs after 5% Bonferroni correction based on chromosome-wide thresholds, determined using the number of independent genomic segments. A total of 143, 62, and 71 significant SNPs were identified for ADGpre, ADGpost, and ADGfull. Notably, candidate regions on BTA29, and BTA23 contained genes previously linked to growth, and immune response, including IGF2, INS, TNF, and LTA, which have been associated with average daily gain, growth rate, metabolism of lipids in both beef and dairy cattle populations, and to the Bovine Luekocyte Antigen region. Functional enrichment analysis performed with GALLO revealed pathways related to cell energy metabolism and protein synthesis and destabilization, highlighting coordinated and complex biological processes related to growth during the pre and post weaning phases of crossbred calves. These results provide insights into the genetic architecture of growth in crossbred dairy calves. The discovery of loci and pathways offers opportunities to enhance genomic selection strategies, supporting improvements in calf performance, production efficiency, and overall profitability within dairy and beef systems.

Keywords: 2026

How to Cite:

Lopes, L., Schenkel, F., Hermisdorff, I., Steele, M., Baes, C. & Renaud, D., (2026) “Genomic analysis of weight gain in crossbred dairy calves”, World Congress on Genetics Applied to Livestock Production Digital Archive 2026(1): 2285876. doi: https://doi.org/10.31274/wcgalp.23814

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