Improvement in Semen Conservation of the Indigenous Czech Endangered Old Kladruber Horse: Special Focus on the Type of Extender and Packaging System.
Authors: Šichtař Jiří, Šimoník Ondřej, Bubeníčková Filipa, Svobodová Jitka, Nehasilová Anežka
Journal: Journal of equine veterinary science
Summary
# Editorial Summary Preserving the genetic diversity of endangered horse breeds through semen cryopreservation requires optimisation of freezing protocols, which is precisely what this 2019 research addressed in Old Kladruber stallions—a critically endangered Czech breed. The researchers compared two extender formulations (Gent and Lactose-EDTA) combined with two packaging systems (5-mL aluminum tubes and 0.5-mL plastic straws), evaluating post-thaw spermatozoan motility via computer-assisted analysis, plasma membrane integrity using fluorescent staining, and apoptotic status across a one-hour post-thaw period on samples from six stallions. The Gent extender substantially outperformed Lactose-EDTA across all measured parameters, yielding superior progressive motility, kinematic characteristics, membrane integrity, and reduced apoptotic changes (all P < 0.05), with the Gent-plus-0.5-mL-straw combination proving optimal for maintaining kinematic parameters and minimising cell death. For breeding programmes utilising frozen semen from this or similarly endangered breeds, these findings suggest that extender choice and packaging dimensions significantly influence post-thaw sperm viability and fertilising potential—factors that breeding coordinators and veterinarians should carefully consider when establishing cryopreservation protocols to maximise genetic retention in conservation efforts.
Read the full abstract on PubMed
Practical Takeaways
- •For breeding programs using Old Kladruber horses or similar endangered breeds, use Gent extender with 0.5-mL plastic straws to achieve optimal post-thaw spermatozoa quality and viability
- •Extender and packaging system selection significantly impacts frozen semen outcomes—practitioners should validate their specific combination choices rather than assuming interchangeability
- •This protocol supports the genetic preservation of endangered Old Kladruber horses through improved artificial breeding efficiency
Key Findings
- •Gent extender produced superior motility, kinematic parameters, and plasma membrane integrity compared to Lactose-EDTA extender (P < 0.05)
- •Gent combined with 5-mL aluminum tubes achieved highest progressive motility and PM integrity; Gent with 0.5-mL straws optimized kinematic parameters and reduced apoptotic changes
- •Frozen-thawed semen showed markedly different outcomes depending on extender-packaging system combination, with Gent and 0.5-mL straws representing the optimal freezing protocol for Old Kladruber stallions