The Mare: A Pertinent Model for Human Assisted Reproductive Technologies?
Authors: Benammar Achraf, Derisoud Emilie, Vialard François, Palmer Eric, Ayoubi Jean Marc, Poulain Marine, Chavatte-Palmer Pascale
Journal: Animals : an open access journal from MDPI
Summary
# Editorial Summary: Equine Models in Assisted Reproductive Technology Research Reproductive biologists have long recognised that whilst equine and human anatomy differs markedly, fundamental processes including follicular development, single ovulation, and early embryonic progression to the blastocyst stage follow similar trajectories—making mares a potentially valuable comparative model for understanding human assisted reproductive technologies. Benammar and colleagues conducted a detailed literature comparison examining how ART protocols diverge between species: horses typically undergo in vitro oocyte maturation without hormonal stimulation (circumventing the inefficiency of ovarian stimulation in mares), whereas humans depend on pharmacologically-induced follicular recruitment; equine embryo production relies exclusively on intracytoplasmic sperm injection, contrasting with the dual approach of conventional IVF and ICSI in human medicine; and blastocyst-stage transfer is standard in equine practice whilst humans routinely transfer earlier-stage embryos. Despite these methodological differences, both species contend with age-related and obesity-associated fertility decline, offering scope for reciprocal investigation of infertility mechanisms. The authors conclude that whilst the mare cannot serve as a comprehensive single model for human ART, bidirectional knowledge exchange between equine and human reproductive research could enhance understanding of fundamental reproductive physiology and refine treatment strategies for both populations—particularly regarding cryopreservation optimisation and the physiological impacts of advancing maternal age.
Read the full abstract on PubMed
Practical Takeaways
- •Equine practitioners should recognize that mare reproductive physiology offers comparative insights into infertility mechanisms in both species, particularly regarding age and metabolic factors affecting fertility
- •Understanding species-specific differences in oocyte maturation and embryo transfer protocols is essential when counseling clients about assisted reproductive technology options and outcomes in mares
- •Obesity and advanced age represent modifiable risk factors for reduced fertility in both mares and women, warranting attention to body condition and metabolic management in breeding programs
Key Findings
- •Horses and humans share similar follicular dynamics, mono-ovulation patterns, and embryo development kinetics to blastocyst stage despite anatomical differences
- •Horse oocytes require in vitro maturation without hormonal stimulation, whereas human oocytes are matured in vivo following ovarian stimulation
- •Only ICSI is used for equine embryo production compared to both IVF and ICSI in humans, and equine embryo transfer is restricted to blastocyst stage whereas human transfers occur from four-cell stage onward
- •Equine and human reproduction share common infertility concerns related to aging and obesity, suggesting potential for reciprocal knowledge exchange despite horses being unsuitable as a single model for human ART