Breeding

Success With Cooled Semen

What stallion owners and cooled semen users should know.

Stallion owners who ship cooled semen have a certain amount of responsibility to their clients. The most important responsibility is to provide mare owners with quality semen that survives the cooling and transportation process and arrives on time. Most stallions produce semen that remains viable for extended periods of time after being cooled and shipped. However, some stallions' semen does not survive the cooling process, so it is important that, prior to breeding season, the stallion's semen be evaluated for sperm concentration and motility.

The stallion's semen should undergo a 24-hour viability check to ensure that it survives the cooling process and shipment. The 24-hour test determines if the semen is capable of being stored and shipped, and it also determines which semen extender and antibiotic mixture works best for that particular stallion.

This article discusses the importance of proper procedure with cooled semen. If you want to learn more about frozen semen, check out our "Equine Insemination With Frozen Shipped Semen" DVD.

Semen extenders contain protective ingredients that enhance the survival of the sperm outside the reproductive tract. Lipoproteins in the extender, such as those contained in milk or egg yolk, protect the spermatozoa against cold shock, and the glucose in the extender provides energy for the spermatozoa. Antibiotics are added to extenders to retard or eliminate bacterial growth. The 24-hour test involves the collection of the stallion, evaluation of the semen for mobility and concentration, the addition of an extender and cooling in a transportation container. After 24 hours, the container is opened, and the semen is evaluated again to ensure that it is still viable. Stallion managers might want to evaluate the semen again for viability after a 36- and 48-hour cool storage period. The recommended insemination dose for cooled semen prior to shipment is 1 billion progressively motile sperm cells, twice the recommended fresh insemination dose. It is important that the stallion collection facility or the attending veterinarian possess adequate equipment to evaluate the semen.

On the day of the shipment, the stallion is collected, and the semen evaluated. The semen is then mixed with a prewarmed extender within 15 minutes of collection. The extended semen is placed in a plastic bag and placed in a cup inside the isothermalizer of the shipping container. The sealed semen cup is then placed with cooling cans in the shipment container. The cooling cans gradually cool the semen during shipment. Before the container is sealed, a cooled semen transport sheet is placed inside the container. The sheet contains information on the stallion and mare. It also contains the collection date, time, total semen volume, sperm concentration and motility. This information provides the mare's veterinarian with a set of parameters to compare with the received semen.

Fascinated with the science involved in equine reproduction? Or are you a stallion owner considering offering frozen shipped semen from your stallion? If you answered yes to either of these questions, you should definitely check out AQHA's Equine Insemination With Frozen Shipped Semen" DVD.

Once the semen arrives at the mare's location, it should be immediately removed from the container, aspirated into a sterile syringe and inseminated into the mare. Research has shown that there is no value in warming the semen to body temperature prior to insemination. A small retention sample should be withheld and warmed to body temperature for motility evaluation. This procedure ensures that the semen survived the cooling and shipment process. For more information about equine reproduction procedures, you can also download our FREE Artificial Insemination Fact Sheet.