A novel method for equine embryo transfer from contaminated recipient mares into second healthy recipients for surviving embryos.
Authors: Derbala M K, Abu-Seida A M, El-Metwally A E, Asfour H A E
Journal: Journal of equine veterinary science
Summary
# Editorial Summary Endometritis in recipient mares represents a significant but often underrecognised threat to embryo transfer success, yet this Egyptian study demonstrates a practical solution: when bacterial contamination is detected via ultrasound-guided fluid collection 2 days post-transfer, embryos can be recovered and re-transferred to fresh recipients with substantially improved outcomes. The researchers monitored 25 recipient mares (18 treated, 7 controls) and found that all untreated mares with intraluminal fluid and confirmed endometritis experienced complete embryonic loss by day 14, whilst embryos re-transferred from contaminated mares to healthy recipients achieved pregnancy rates of 66.7% when the embryo had developed a thick protective capsule, compared to only 33.3% for those with normal capsules. Microbiological analysis confirmed mixed or single bacterial infections in the contaminated fluid alongside inflammatory cell infiltration, explaining the embryonic mortality in control animals. For equine practitioners involved in ET programmes, this work underscores the clinical value of pre-transfer endometrial screening and early post-transfer monitoring at 48 hours, since salvageable embryos can be recovered before irreversible damage occurs; implementing such protocols could substantially improve commercial ET success rates, particularly when breeding outcomes depend on valuable genetic material.
Read the full abstract on PubMed
Practical Takeaways
- •Ultrasound screening at 2 days post-ET can identify embryos in contaminated recipients; those detected should be re-flushed and transferred to healthy mares rather than left to die
- •Pre-ET uterine swabbing and bacterial screening of recipient mares significantly improves ET success by preventing embryo loss to endometritis
- •Embryo capsule thickness is a viable indicator of embryo viability after contamination exposure; thicker capsules predict higher pregnancy rates in second recipients
Key Findings
- •All 7 control mares showed embryonic death by 14±1.1 days after ET due to endometritis
- •Re-flushing and re-transferring embryos to healthy recipients resulted in 66.7% pregnancy rate in embryos with well-developed capsules versus 33.3% in those with normal capsules
- •Microbiological examination of retrieved fluid from treated mares revealed mixed and single bacterial infections with polymorphonuclear neutrophils indicating endometritis in all first recipient mares
- •The novel re-transfer method protected 12/18 embryos (66.7%) from inflammatory damage, allowing survival in healthy second recipients