Services

SBS Quality Control Program
Freezing Equine Semen
Frozen Semen/Embryo Storage
Frozen Semen Distribution
Import and Export of Frozen Semen
Embryo Freezing
Breeders Support for Stallion Clients

Freezing Equine Semen

Frequently Asked Questions

After a stallion has been properly "cleaned-out" to delete the old sperm stored in the reproductive tract, SBS labs perform one or more test freezes on each new stallion. This test freeze is critical because it allows us to customize a semen freezing protocol most suitable for each stallion. Customized protocols differ in the centrifugation and freezing extenders used and the cooling rates employed by the controlled rate freezers. Regardless of the protocol used however, the basic elements of the semen freezing process are the same.

Immediately following the collection, a small sample

Computer Assisted Sperm Analysis

of the semen is analyzed to determine sperm concentration and quality. In many SBS labs, sperm motility is analyzed using state-of-the-art computer assisted analyzers, which provide objective and accurate measurements of sperm motion characteristics. The fragile semen is diluted and centrifuged to remove the majority of the seminal plasma, which can be harmful to sperm during the freezing process. Centrifugation also concentrates the sperm so that a sufficient number of motile sperm can be included in a single insemination dose.

After the seminal plasma has been removed, the sperm pellet is resuspended in an extender which contains ingredients to protect the fragile sperm during the ensuing freezing and eventual thawing processes. As a critical quality control measure, all extenders used at SBS affiliate labs are manufactured at the SBS lab in Maryland using the highest quality reagent grade chemicals and ultra pure water. The pH and osmolarity of all extenders is measured and recorded for each lot of extenders produced to ensure the appropriate environment for maintaining sperm viability.

All SBS laboratories utilize controlled rate cell freezers.

Once extended, sperm are then loaded into 0.5 ml plastic straws. Each stallion's straws are preprinted and uniquely marked with the stallion's name and registration number as well as the year frozen, lot number, location of the freezing site and USDA lab number.

Once all of the semen is loaded, the straws are placed in a controlled rate cell freezer. The rate at which the semen is cooled from room temperature to the desired -196°C is variable and dependent upon the specific procedure selected from the test freeze results.

After the semen has completed the freezing process, it is then immersed and maintained in liquid nitrogen in special cryogenic containers. Based on studies it is estimated that frozen semen will last 50,000 years if maintained properly in a nitrogen tank.