Impaired Reproductive Function in Equines: From Genetics to Genomics.
Authors: Laseca Nora, Anaya Gabriel, Peña Zahira, Pirosanto Yamila, Molina Antonio, Demyda Peyrás Sebastián
Journal: Animals : an open access journal from MDPI
Summary
# Editorial Summary Reproductive performance directly impacts economic viability across the equine industry, yet genetic contributions to fertility—particularly in mares—remain poorly understood despite their substantial complexity. This 2021 review synthesises current genomic methodologies now available for identifying heritable reproductive disorders in horses, ranging from established chromosomal abnormalities and point mutations to emerging techniques for detecting copy number variants and molecular homozygosity through genome-wide association studies. The authors highlight that inbreeding and increased homozygosity have been strongly implicated in subfertility and infertility cases, whilst candidate genes influencing fertility traits continue to be identified as sequencing technologies improve. A critical barrier to advancing this field is the scarcity of large, rigorously documented phenotypic datasets linking reproductive outcomes to genetic markers, though accumulating genomic tools now make such investigations feasible. For practitioners, this work underscores the value of genetic screening in breeding programmes—particularly when selecting against lines with known chromosomal anomalies or elevated homozygosity—and suggests that collaborative data collection on fertility outcomes could unlock substantial improvements in reproductive efficiency within studs and breeding operations.
Read the full abstract on PubMed
Practical Takeaways
- •When dealing with subfertile or infertile mares, consider requesting genetic screening for chromosomal abnormalities and inbreeding coefficients, as these are now detectable through modern genomic techniques
- •Breeders should be aware that molecular homozygosity is an evidence-based risk factor for reproductive failure and should assess breeding decisions accordingly
- •The field of equine reproductive genetics is rapidly evolving; stay informed about emerging genomic testing options that could help identify genetic causes of fertility problems in your client base
Key Findings
- •Genetic causes of reproductive disorders in equines remain poorly understood, particularly in mares, despite fertility being critical to economic success of the equine industry
- •Chromosomal abnormalities have been associated with infertility in horses for over 50 years, and new genomic methodologies now enable improved detection of these abnormalities
- •Inbreeding and molecular homozygosity have been identified as major contributors to low reproductive performance in horses
- •Copy number variants and candidate genes identified through genome-wide association studies show promise for understanding reproductive performance, but research is limited by scarcity of large, accurate phenotypic datasets