The use of sex-sorted semen in horses.

This research article investigates the viability of using sex-sorted semen in horses, particularly the challenges and efficiency associated with transportation and preservation. The study found that despite a slight increase in lipid peroxidation, the quality of sorted sperm was tantamount to conventional semen, with evidence of success in embryo production when used in intracytoplasmic sperm injection procedures.

Research Purpose and Methodology

• The main aim of this study was to explore the feasibility and practicality of using sex-sorted semen in horses. This process was previously hindered due to differences in reproductive physiology and variations in equine semen quality.
• The study sought to overcome challenges associated with transport of the cooled semen to a central sorting facility, minimizing oxidative stress and DNA fragmentation, and effective methods for short or long-term preservation of the sorted sperm.
• For evaluation, equine semen was shipped to a central facility at a cooled temperature (8°C) and examined for sperm quality post-sorting and preservation.

Research Findings

• The study reported significant improvements in the efficiency of the sex-sorting process, leading to enhancements in sperm motility, morphology, viability, and DNA fragmentation.
• Despite a slight, consistent increase in lipid peroxidation in the sex-sorted sperm, its quality over the first 24 hours was found to be comparable to that of conventional cool-shipped semen.
• Fertility rates with fresh semen did not differ between conventional and sex-sorted sperm, indicating the potential usability of sorted semen in live breeding scenarios.

Implications and Limitations

• The use of frozen-thawed sex-sorted sperm for a procedure known as intracytoplasmic sperm injection (ICSI) consistently produced embryos, although at slightly lower rates than conventional semen for the same stallions.
• A higher number of embryos of the desired sex were obtained when using sex-sorted semen for ICSI, indicating the effectiveness of this method in sex-selection procedures.
• However, there was a observed variability in results that may be attributed to stallion-specific differences. This suggests that the efficacy of sex-sorting could be dependent on individual stallion factors and should be considered in future applications of this process.