Genome-wide association study for methane emission traits in Danish Holstein cattle

Area of Science:

• Animal Genetics
• Agricultural Science
• Environmental Science

Background:

• Reducing methane emissions in cattle is crucial for environmental sustainability.
• Understanding the genetic basis of different methane emission phenotypes is essential for effective breeding programs.
• Previous studies have suggested various methane phenotypes, but their genetic correlations remain poorly understood.

Purpose of the Study:

• To investigate the genetic architecture and correlations of eight different methane emission traits in Danish Holstein cattle.
• To identify single nucleotide polymorphism (SNP) and genomic regions associated with methane emission traits using Genome-Wide Association Studies (GWAS).

Main Methods:

• Genome-Wide Association Studies (GWAS) were conducted on 1,962 Danish Holstein cows with genotypic data and repeated records for eight methane traits.
• Traits analyzed included methane concentration (MeC), methane production (MeP), residual methane (RMETc, RMETp), methane intensity (MeIc, MeIp), and methane yield (MeYc, MeYp).
• Genomic segments of 1 Mbp were tested for association, identifying significantly associated regions and SNPs.

Main Results:

• Strong associations were identified on chromosome 13 for MeC, MeP, and MeYc, and on chromosome 26 for MeC, MeP, MeIp, MeYp, and MeYc.
• Suggestive association signals were found on chromosome 1 for MeIc, MeIp, RMETc, MeYc, and MeYp.
• Methane concentration (MeC) and methane production (MeP) shared the highest number of significantly associated genomic segments (17) and SNPs (23-25), primarily on chromosomes 11, 13, and 26.

Conclusions:

• Methane concentration (MeC) and methane production (MeP) exhibit the strongest genetic correlation among the analyzed methane emission traits.
• These findings suggest that MeC and MeP are the most biologically relevant phenotypes for genetic selection aimed at reducing methane emissions in cattle.
• The identified genomic regions provide targets for future genetic improvement strategies in dairy cattle for lower methane output.