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Stallion Services > Freezing of Semen

Freezing of semen is a great insurance policy for your stallion. It can also preserve a stallion's genetics long after he has passed. Currently the only way to know if a stallion's semen will freeze successfully is to do a test freeze. During a test freeze, a collected sample of semen will be evaluated, centrifuged to concentrate cells, and re-suspended in a freezing extender. For a test freeze, several different freezing extenders may be trialled. A calculated number of cells are then placed in .5mL straws and put through the freezing process.

The number of straws frozen per collection varies greatly between stallions depending on volume and concentration of live sperm from collection. An average may be around 40-50 straws per freeze, however during the 2011/2012 season QEC had a range of 20-95 straws per freeze.

After the batch of straws has been frozen, a test thaw of one or more straws will be done to determine motility of the thawed semen. Ideally, the post thaw motility should be around 40-50%, but this will vary by stallion. Depending on the post thaw motility, the number of straws required to meet the 400 million sperm insemination dose can be determined. Usually there are 6-8 straws required per dose.

Please understand that not all stallions will freeze well. Also, not every semen collection may meet requirements for freezing, even from stallions who do freeze well.

The resulting straws of semen will need to be stored in liquid nitrogen tanks, and if handled properly could last indefinitely. When using frozen semen doses, keep in mind that the freezing process takes a toll on the sperm cells, weakening them and perhaps reducing capability of the sperm. While the thawed semen may have a good percentage of progressively motile sperm, this does not always equate to a high percentage of pregnancies. The fertility of the frozen semen cannot be determined until it is tried in a mare. To obtain maximum success with frozen semen, choose mares that are young, fertile, and without previous reproductive problems.

Freezing Semen expected costs:

Stallions that have not serviced mares recently may need several collections prior to freezing to reduce the number of dead sperm in the ejaculate (clean out collections). Or, if he has not been collected at all he may need AV training sessions as described above. Stallions that have not been frozen previously at QEC will need a collection and test freeze. If test freeze proves successful, additional freezes can be done. If test freeze is unsuccessful, the stallion owner will discuss options with a QEC veterinarian, and could have the option to do another test freeze or quit. There is also a straw printing fee and a liquid nitrogen storage fee. Depending on the quality of semen, stallions may be frozen 3-5 times per week (assuming no other breeding is being done by stallion at the time). Stallion agistment fees will apply for his stay (please see Stallion Care Section for details).

When bringing your stallion to QEC, have an idea of how many doses you may like to freeze. Keep in mind that each mare may require more than one dose of frozen semen to conceive. After the first few collections, veterinarians at QEC will have an idea of how many straws are likely to be frozen per collection and will contact the stallion owner to discuss. (Link to email request for costs for semen freezing costs)