[Successful use in horses of deep-frozen semen specimens stored for 18 years].

The research article discusses a successful experiment where semen from a Haflinger-stallion, frozen for 18 years, was used to inseminate mares with favorable results, demonstrating that long-term storage of frozen semen does not diminish its viability for successful conception.

Methodology and Process

• In 1970, semen was collected from a Haflinger-stallion and frozen using the pellet method, a technique used in cryopreservation that involves freezing the semen in a special machine that ensures uniform freezing rates. This method reduces the chances of damaging the sperm cells.
• After 18 years of storage in liquid nitrogen, the semen was thawed and used to inseminate four mares. The insemination of each mare was performed shortly after ovulation, with each receiving varying amounts of motile sperm ranging from 150 million to 636 million. The motility of the sperm ranged between 20% and 40%, meaning that this percentage of the sperm in the semen sample showed movement and therefore, potential for fertilization.

Results and Conclusions

• Remarkably, three of the four mares conceived after a single insemination procedure. The remaining mare needed four insemination attempts over the course of three ovulation periods but eventually also conceived.
• All of the pregnancies resulted in live births, with three foals being born already and the fourth mare still being pregnant at the time of the research report.
• The success of the insemination using the long-stored semen demonstrates that such semen, if stored properly in liquid nitrogen, retains its fertilizing capacity for an extensive period of time.
• The practical implication of this finding is that it opens up possibilities for assisted reproductive techniques in horses, and potentially other animals, allowing semen to be stored and used with success many years later. This could aid in breeding programs and the preservation of valuable genetic traits.