Genome-wide association study for longevity in the Holstein cattle population

Area of Science:

• Animal Genetics
• Dairy Science
• Quantitative Genetics

Background:

• Dairy cow longevity is crucial for profitability.
• A decline in average culling age has been observed in recent decades.
• Identifying genetic factors influencing longevity is essential for improving dairy herd management.

Purpose of the Study:

• To identify genes associated with dairy cow longevity.
• To analyze the genetic basis of traits such as days in production, days in herd, and number of calvings.
• To detect quantitative trait loci (QTL) influencing longevity.

Main Methods:

• Genome-wide association analysis (GWAS) was conducted on 946 genotyped dairy cows.
• Data included dates of birth, calving, culling, and production yields.
• The GenABEL package in R was utilized for the analysis.

Main Results:

• Five genome-wide significant single nucleotide polymorphisms (SNPs) associated with all three longevity traits were identified.
• Two suggestive QTL regions on chromosomes 16 and 30 were detected.
• Genes within these QTL regions are involved in fertility, reproductive health, heat stress, and welfare.

Conclusions:

• The study identified significant genetic markers associated with dairy cow longevity.
• These findings provide a basis for developing improved breeding strategies.
• Enhancing longevity through genetic selection can improve dairy cow welfare and farm economic viability.