You have made the decision to breed your mare using frozen semen, now what? The choice of breeding your mare with frozen semen over cooled or fresh semen has a few notable benefits. Aside from the expanded availability of stallions available to you with frozen semen, e.g. those that are located in another country, are limited by their competition schedule or are deceased, another big advantage of frozen semen is that the shipment can be sent out ahead of time so it is ready and waiting on your mare to ovulate; as opposed to your mare waiting on the semen to be collected from the stallion, processed and cooled, and finally shipped out to you. Nonetheless, despite this added convenience, it is important to be prepared and plan ahead for your frozen semen shipment. That way you are fully prepared when the time comes to request and receive your shipment in order to optimize your chance of a successful breeding.
Ordering your Frozen Semen Shipment
Once your breeding contract has been secured with the stallion owner, it is a good idea to call the distribution center where the stallion’s frozen semen is stored, so you can ask them about their policies and protocols with respect to requesting a frozen semen shipment, for example:
- How much notice do you have to give them when you need to order frozen semen?
- What is the protocol for requesting a shipment? Do you have to call in or can you fax/email a request? What are their office hours?
- What days do they ship frozen semen? Can you get Saturday delivery?
- How do they ship frozen semen? What type of shipping container do they use?
- How long is the tank rental period? How long will the tank maintain temperature?
- How do you return the tank to them?
- What kind of instructions and information do they include about the semen quality and how to handle the straws for thawing an insemination?
- What are their fees for a shipment of frozen semen storage?
- If you are a Canadian breeder, what additional steps do you need to take
At both Select Breeders Services distribution locations in Maryland and Texas, a frozen semen request received by 1pm will ship same day via FedEx Priority Overnight. SBS does require an authorization on file from the stallion owner specifying the number of doses (per season and per cycle) that have been approved for release to the mare owner for each mare. A frozen semen shipment will not go out unless we have authorization from the stallion owner on file. Therefore, it is a good idea to call in advance to be sure that the authorization is on file for you, in order to avoid last minute delays on the day of shipment when you would be responsible for tracking down the stallion owner to provide their authorization. At SBS we allow a two week rental period on all shipping containers during the breeding season. This means the frozen semen shipment can be ordered in advance of ovulation, when the mare first starts coming into heat, so it is there ready and waiting when she needs to be bred. Please note that not all distribution centers can be so responsive or have sufficient tanks available to allow for such a long rental period. Some distribution facilities may require over 24hrs of notice prior to shipping out frozen semen and the tank rental period may be only 2-3 days.
Receiving a Frozen Semen Shipment
Your frozen semen tank has arrived! First, inspect your shipper for any evidence of tampering prior to inspecting the contents. As with shipments of any goods or products, there is always the possibility of finding out a tank has been tampered with prior to arrival. At Select Breeders Services, we use tamper evident red zip ties (photo right) on every shipment. Should you notice that the tank is not secured upon arrival, call the distribution center immediately to report this matter. Once it has been determined the tank has arrived in the secured fashion to which it departed the distribution center, it is time to examine the contents. Stallion owners typically require immediate notification of any damage to the straws sustained during shipment. It may be possible to send a replacement shipment before your mare needs to be bred.
First inspect any paperwork sent with the frozen semen shipment, usually this should include information about the semen quality and thawing and handling instructions. Included in all SBS frozen semen shipments is an envelope of important information (photo above left), including LN2 Safety Instructions, a detailed transaction report regarding semen quality, thawing and handling instructions, an insemination certificate (if appropriate), instructions for tank return, a return FedEx airbill and address label. If the tank had been tampered with during shipment this envelope of information may be missing. Call the distribution center to let them know this is the case and a copy of the materials can be faxed or emailed to you. Confirm by referring the transaction report that the correct semen has been sent to you. Familiarize yourself with the thawing instructions so you can prepare the necessary equipment to handle the straws appropriately when required. Share this packet of information with your veterinarian in advance of the breeding as this may influence his decision about how best to manage your mare.
While frozen semen shipments are sent out in a dry vapor shipper, i.e. no liquid nitrogen is contained within the tank, the internal temperature remains at approximately -196° Celsius. Review the liquid nitrogen safety instructions and use appropriate caution before handling the shipping container and straws. As you remove the lid of the shipping container and peer inside you will notice a ring of frost half way down the neck of the shipping container. It is important not to raise the canister of straws contained within the shipping container above this frost line (photo middle left). Above the frost line the temperature of the tank is not maintained. Exposure of frozen semen straws to the elevated temperatures within the upper portion of the neck of the shipping container or the ambient air temperature outside the tank can compromise the semen quality. Just a simple visual assessment of the straws should be sufficient to determine the number of straws included in the shipment and that they are still securely packaged.
It is not recommend that you handle the straws of frozen semen unless you are comfortable and have experience doing so - better to leave this to your veterinarian if you are at all unsure about the process – no need to risk compromising the semen quality. Do not handle straws of frozen semen unless you use pre-cooled forceps or tweezers. You can cool them off by holding the tools below the frost line within the neck of the shipping container for several minutes. It is difficult to safely handle the straws and review the identity and integrity whilst working within the limited dimensions of the shipping container - best to leave this to your veterinarian or just to wait until the time of thawing. If a thorough inspection and inventory of the straws is necessary prior to insemination we would recommend preparing a bath of liquid nitrogen in a polystyrene box. This way the straws can be transferred from the shipping container to the nitrogen bath and can then be safely handled and inspected under liquid nitrogen.
Transferring Frozen Semen to Storage Tanks
Even with the available extended rental periods, it can be beneficial to transfer your doses of frozen semen to a holding tank on site or at your veterinarian’s office for temporary storage. At Select Breeders Services, we offer the option of shipping on canes or in bulk goblets. Check at your final destination as to which method is preferred prior to placing your shipment order with the distribution center. This way the straws will arrive packaged ready for storage in the fashion that is most convenient to you or your veterinarian. Ensure that only someone skilled in the handling of frozen semen is transferring the straws of frozen semen from the shipping container to the storage tank.
Included in the SBS shipment information packet are thawing and handling instructions for frozen semen. As described above, use pre-cooled instruments for handling the straws and always work below the frost line. Ahead of time locate the tank and storage compartment where you intend to transfer the straws. Set the shipping container beside the storage tank and remove the corked lids from both tanks. Confirm that the selected location in the storage tank is empty and available to receive the semen. Holding the handle of the canister containing the straws of frozen semen within the shipping container with one hand, carefully and securely grasp the cane or goblet of straws with the pre-cooled forceps, hemostats or tweezers using the other hand. Providing the goblet or cane of straws is safely secured (photo right), continue to hold them below the frost line of the shipping container. With the other hand release the handle of the shipping container canister and then turn to the storage tank and pick up the handle of the canister within the storage tank where you will be transferring the semen. Visually locate by eye (photo bottom left) where you will be transferring the semen, then quickly and smoothly in one efficient motion transfer the goblet or cane of straws from the shipping container to the appropriate location in the storage container. Secure the canister back into position within the storage container. If the semen you have just transferred is not submerged under liquid nitrogen it is recommended that you fill the storage tank with liquid nitrogen at this time.
One thing to bear in mind when transferring 30mm goblets of straws is that if there are no holes punched into the bottom of the plastic goblet when the goblet of straws is transferred to the storage tank and submerged in liquid nitrogen the nitrogen will flood over the top of the goblet This can often occur with sufficient force to flush the straws up and out of the goblet into the body of the storage container. Straws can easily be lost to the bottom of the tank when this occurs. Therefore, when lowering the goblet of straws carefully and slowly submerge the goblet into the liquid nitrogen so the goblet fills in a controlled manner. Alternatively, you can add liquid nitrogen to the goblet of straws within the shipping container. That way they are less likely to float away when the level of liquid nitrogen equilibrates between goblet and tank. At SBS, we puncture goblets of all sizes used for frozen semen shipments with tiny holes so that when transferring semen to storage the goblet will slowly fill from the bottom of the goblet with liquid nitrogen as it is submerged into the tank.
Thawing instructions vary depending upon the size of the straw and also the laboratory that processed the frozen semen. For 0.5mL straws frozen by SBS, the thawing time is a minimum of 30 seconds at 37degrees Celsius. Our thawing and handling instructions are provided in the shipping container and on our website, here. We also have an FAQ on our website that provides more detailed information on how to thaw straws and the equipment required. FAQ: Is it difficult to thaw and inseminate with frozen semen?
For a variety of reasons, it may arise that there are straws or doses of frozen semen that have not been used on the mare for which they were originally intended. The first thing to determine is who owns the frozen semen. If the frozen semen was purchased by the dose any remaining straws/doses you can save for future use, as it is yours. If you received the frozen semen as part of a breeding contract then the stallion owner still owns the frozen semen. Referring back to your original contract with the stallion owner will help guide you in the right direction with respect to what you should do with unused semen; to destroy the semen, keep it, or send it back to the distribution center. For more information see our blog article, Three Ways Stallion Owners Can Prevent Unapproved use of Frozen Semen, and the FAQ: What do I do with unused frozen semen?
Once your mare has been successfully bred or the semen has been transferred to temporary storage the matter of returning the tank arises. Tank return is the responsibility of the mare owner. Included in the distribution fee paid to SBS is a prepaid return FedEx air bill. Simply close the dry shipper with two zip ties to ensure the lid is secure, affix the prepaid air bill and pre-printed address label, then drop it off it to your local FedEx location. Should you find that no return air bill was included with the original shipment, be sure to call the distribution center for further instructions. If you find that even with the extended rental period, retaining the tank for a longer period of time is necessary, alert the distribution center as additional fees may apply if the tank is not received by the predetermined return date. Furthermore, the tank may not be rated to hold temperature for a longer period.
The beauty of placing an order for frozen semen is that not only can it be ordered and immediately used but it allows for planning on the mare owners end. An order placed in advance can be on site waiting for the perfect window of opportunity to inseminate the mare. No more panicking because a stallion couldn’t be collected or the snow storm of the century has delayed delivery - the semen is ready and waiting for you.