Genome-wide association study for selected cheese-making properties in Dual-Purpose Belgian Blue cows

Area of Science:

• Animal Genetics
• Dairy Science
• Quantitative Genetics

Background:

• Cheese-making properties (CMP) are crucial for dairy cattle breeding.
• Understanding the genetic basis of CMP in Dual-Purpose Belgian Blue (DPBB) cows is essential for improving milk quality and cheese yield.
• Previous research has not fully elucidated the genomic regions associated with CMP in this specific breed.

Purpose of the Study:

• To estimate genetic parameters for CMP in DPBB cows.
• To identify specific genomic regions associated with CMP using SNP data.
• To provide a basis for genomic selection to enhance cheese-making traits in DPBB cattle.

Main Methods:

• Utilized a large dataset of test-day records (milk yield, fat, protein, casein, calcium content, coagulation time, curd firmness, titratable acidity) from DPBB cows.
• Employed random regression test-day models and Bayesian Gibbs sampling for genetic parameter estimation.
• Applied a single-step genomic BLUP approach and genome-wide association analyses with 28,266 SNPs across 29 bovine autosomes.

Main Results:

• Heritability estimates for CMP ranged from 0.19 to 0.50.
• Significant genetic correlations were observed between coagulation time, curd firmness, and milk composition traits.
• Genome-wide association studies identified four significant genomic regions on BTA1, BTA3, BTA7, and BTA11 associated with CMP, with variations between parities and lactation stages.

Conclusions:

• The identified genomic regions provide valuable targets for marker-assisted selection to improve CMP in DPBB cows.
• Distinct genetic architectures for CMP exist between parities and lactation stages, suggesting complex inheritance patterns.
• This research lays the foundation for implementing genomic evaluations to enhance cheese production efficiency in the DPBB breed.