A New Approach of Sperm Motility Subpopulation Structure in Donkey and Horse.
Authors: Gacem Sabrina, Valverde Anthony, Catalán Jaime, Yánez Ortiz Iván, Soler Carles, Miró Jordi
Journal: Frontiers in veterinary science
Summary
# Editorial Summary: Sperm Motility Subpopulation Differences in Equines and Donkeys Understanding species and breed differences in semen quality requires sophisticated analysis tools, and this 2021 research applied high-speed videomicroscopy (250 frames per second) to characterise sperm kinematic parameters across 57 ejaculates from Spanish horses, Arabian horses, and donkeys using the ISAS® v1.2 system. Donkey spermatozoa demonstrated superior motility across most parameters—travelling faster and with greater linearity than equine sperm—whilst Spanish horses outperformed Arabian horses in velocity metrics, though Arabian sperm showed greater linearity. Principal component analysis revealed three distinct motile subpopulations in both species, with the dominant subpopulation (38–42% of sperm) characterised by rapid, straight, linear movement with high flagellar beat frequency, whilst the smallest subpopulation comprised slower, non-linear cells. These findings have important implications for practitioners involved in breeding programmes and semen evaluation: breed-specific reference ranges are necessary for accurate assessment, and high-resolution kinematic analysis provides a more nuanced understanding of ejaculate quality than traditional motility scoring alone. For studs and equine reproduction specialists, this work underscores the need to account for inter-breed variation when interpreting semen analysis results, particularly when comparing donor animals or troubleshooting fertility issues across different bloodlines.
Read the full abstract on PubMed
Practical Takeaways
- •Breeding soundness evaluations should account for species and breed differences in sperm motility patterns; donkeys naturally have faster, more linear sperm than horses
- •When comparing semen quality between individual stallions or donkeys, use consistent breed-specific reference ranges rather than pooled data, as breeds show measurable kinematic differences
- •Advanced sperm analysis equipment (250 fps recording) provides better discrimination of sperm subpopulations and may improve fertility prediction compared to conventional methods
Key Findings
- •Donkey sperm demonstrated significantly higher kinematic parameters than horse sperm across most measures, being faster and more linear
- •Three distinct sperm subpopulation structures were identified in both donkeys and horses, with the dominant subpopulation (38.2-41.7%) characterized by rapid, straight, and linear movement with high beat frequency
- •Spanish horse breed showed higher average path velocity and curvilinear velocity compared to Arabian horses, while Arabian horse sperm exhibited greater linearity
- •High-speed recording at 250 frames per second revealed breed-specific and species-specific differences in sperm motility that standard analysis might not detect