Genetic Insurance for Your Soon-To-Be-Gelding

Most stallions three years of age or older are candidates for this program. We do not typically recommend freezing sperm from two-year-old colts as many times these animals have not yet reached maturity and produce only low numbers of less fertile sperm. Yearlings and younger colts are not eligible.

From your perspective, nothing changes. The castration procedure is performed as usual. But now, instead of wondering whether or not you may have lost a great line, you can walk away knowing that you have taken out ‘genetic insurance’ on your horse. If he turns out to be a future superstar, you can still obtain offspring from him.

Just let your surgeon know that you are interested in the Genetic Insurance Program for Geldings. Your surgeon can then put you in touch with one of or our reproduction specialists.

Sperm are frozen in small, 0.5 ml plastic straws labelled with the stallion’s name and breed as well as the date of the freeze. Typically, four-eight straws are used to make one breeding dose. The straws are stored in liquid nitrogen at ( -)180 degrees centigrade and, if properly stored, should be preserved indefinitely.

Mares bred with frozen semen have to managed more carefully than mares bred with cooled or fresh semen because they need to be bred very close to the time of ovulation.

Mare owners should be sure that the veterinarian working with the mare is familiar with the use of frozen semen.

Mares can be managed and bred here at New Bolton or the frozen straws can be shipped anywhere in the United States in special liquid nitrogen shipping tanks to breed mares offsite. The straws are thawed immediately prior to inseminating the mare.

This varies tremendously depending on the innate fertility of your stallion. More mature stallions with larger testicles typically will produce more breeding doses than younger colts with smaller testicles. An average adult stallion (over 3 or 4 years of age) can produce 20 to 40 breeding doses or more.

As for other methods of breeding, pregnancy rates in mares bred with cryopreserved (frozen) epididymal sperm depend very much on the innate fertility of the stallion.  Early work suggested that pregnancy rates in mares bred with frozen/thawed epididymal sperm were lower than those achieved with sperm frozen by more conventional means (e.g., after semen collection from an intact stallion).  However, two more recent studies, including one performed at New Bolton Center, have shown that pregnancy rates with frozen epididymal sperm can be similar to those achieved with conventionally collected frozen sperm.  This type of success has only been reported with careful stallion selection, careful attention to detail during the freezing process, breeding mares with generous numbers of frozen/thawed sperm, and monitoring the mare’s estrous cycle very closely to be sure that breeding occurs close to ovulation.  As one of the first groups to report these high pregnancy rates with epididymal sperm, veterinarians at the Hofmann Center for reproduction are well-prepared to optimize the process for your stallion.  However, because these high success rates appear to be more difficult to achieve with epididymal sperm compared to ejaculated sperm, we recommend choosing to freeze epididymal sperm only when collecting ejaculated semen collection is not an option.  Freezing epididymal sperm is typically used in cases where a stallion dies unexpectedly or, in some instances, following routine castration when an owner prefers that the stallion not have semen collected either due to physical limitations or other concerns.