Genome-wide association with delayed puberty in swine

Area of Science:

• Animal Genetics
• Reproductive Biology
• Swine Production

Background:

• A significant percentage of gilts fail to farrow, impacting herd profitability.
• Reproductive issues like anestrus and failure to conceive are primary reasons for gilt removal.
• Genomic tools for selecting gilts with reproductive longevity are highly desirable for producers.

Purpose of the Study:

• To identify genetic markers associated with failure to attain puberty in gilts.
• To investigate the potential of genomic selection for improving gilt reproductive performance.
• To understand the genetic basis of pubertal attainment in swine.

Main Methods:

• Genotyping of gilts that failed to display estrus (cases) and their pubertal littermates (controls) using the Illumina Porcine SNP60 Beadchip.
• Association analysis of single nucleotide polymorphisms (SNPs) with pubertal attainment.
• Fine-mapping of significant genetic regions, including the chromosome 4 region surrounding the NHLH2 gene.

Main Results:

• Twelve significant SNP associations were identified in the final analysis.
• A highly significant association (P < 1.5 × 10⁻¹⁴) was found on chromosome 4, near the NHLH2 gene, linked to failure to attain puberty.
• The NHLH2 gene has previously been associated with delayed pubertal development in mice.

Conclusions:

• The NHLH2 gene region on chromosome 4 is strongly associated with delayed pubertal development in gilts.
• Identifying genes influencing pubertal age contributes to understanding reproductive development and fertility in swine.
• Genomic selection based on these findings could enhance gilt reproductive longevity and overall herd productivity.