Hysteroscopic insemination of mares with low numbers of nonsorted or flow sorted spermatozoa.
Authors: Lindsey A C, Morris L H A, Allen W R, Schenk J L, Squires E L, Bruemmer J E
Journal: Equine veterinary journal
Summary
# Editorial Summary: Hysteroscopic Insemination with Low Sperm Numbers in Mares When working with subfertile stallions or preserved semen, practitioners often face the challenge of maximising fertility with minimal sperm availability. This 2002 study compared two insemination methods—ultrasound-guided deep uterine placement versus hysteroscopic deposition at the uterotubal junction—using only 5 million spermatozoa per insemination, alongside an assessment of sex-sorted semen viability. Forty oestrus-synchronised mares received either nonsorted sperm via ultrasound guidance (0% pregnancy rate), nonsorted sperm via hysteroscopy (50% pregnancy rate), or flow-sorted sperm via hysteroscopy (25% pregnancy rate), demonstrating that hysteroscopic placement was substantially more effective than ultrasound-guided deposition for low-dose insemination. Critically, pregnancy rates with sex-sorted spermatozoa remained reasonable at 25%, suggesting that the additional processing involved in flow cytometric sorting does not markedly compromise fertility outcomes when combined with precise placement techniques. For practitioners managing valuable or limited genetic material, these findings indicate that hysteroscopic insemination offers a viable strategy to maintain acceptable conception rates even with severely restricted sperm numbers, though the trade-off in pregnancy rate with sorted semen warrants careful consideration against any breeding objectives that depend on sex selection.
Read the full abstract on PubMed
Practical Takeaways
- •Hysteroscopic insemination technique should be preferred over ultrasound-guided uterine deposition when working with subfertile stallions or very low sperm numbers in mares
- •Flow-sorted spermatozoa can be used for sex-selection breeding without significantly compromising pregnancy rates when combined with hysteroscopic insemination
- •Placement of spermatozoa at the uterotubal junction papilla via hysteroscopy improves fertilization efficiency compared to proximal uterine horn deposition
Key Findings
- •Hysteroscopic insemination achieved 50% pregnancy rate (5/10) with 5×10⁶ nonsorted spermatozoa compared to 0% (0/10) with ultrasound-guided deposition (P<0.05)
- •Flow-sorted spermatozoa via hysteroscopic insemination resulted in 25% pregnancy rate (5/20), not significantly different from nonsorted spermatozoa (P>0.05)
- •Hysteroscopic placement of spermatozoa onto the uterotubal junction papilla was more effective than deep uterine horn deposition when using low sperm numbers