By William E. Schultz, D.V.M.
When a natural breeding does not work or is not possible due to scheduling or death of a stud dog, we have choices in the type of breeding to be done. Natural breeding, when possible, is always a good choice. With artificial insemination and progesterone timing, we have the ability to increase conception rates without the necessity of both the sire and dam being present. Chilled semen and frozen semen have greatly increased the flexibility of today’s breedings. Semen can also be collected and stored as a fresh chilled sample for several weeks before the actual breeding.
Chilled semen breedings have been done for over 30 years. Prior to the development of current semen extenders, boiled skim milk was used. We now have options with several companies making shipping kits and proprietary extenders. These kits are available for shipment overnight to almost anywhere in the North American continent and to some European countries that will accept samples without quarantine.
A chilled semen breeding begins by collecting the semen and isolating the sperm rich fraction. This is then centrifuged and extended with a solution that nourishes the semen for several days. This allows for shipment and delivery of viable semen. If a male has not been used for chilled semen previously, we recommend a semen longevity test. The sample is collected and extended the same as for a shipped sample however it is then placed in a water bath and refrigerated for up to several weeks. The sample is examined daily to determine the viability of the semen. This is the same method used to store a sample if a male is alive but unable to be present for breeding. Note: A gradual loss of sperm motility over 5 to 7 days is expected. If the sample is to be used in the future, the extender should be changed every 5 to 7 days until needed for breeding.
Frozen semen has been used in the canine for over 30 years as well. Originally, vaginal cytology was the only timing method used and conception rates were very low The capability of accurate progesterone and leuteotropic hormone (LH) analysis has dramatically improved the success of frozen semen breeding. Progesterone testing has been discussed in another article that is available on this website. Overwhelmingly, frozen semen is used along with surgical insemination for the best results. It is possible to use frozen semen vaginally but the results are less than desirable.
Transcervical insemination (TCI) is being used with good results. In our experience, TCI has worked well in our practice if two inseminations are done 8 to 12 hours apart. The only drawback is that this requires twice the semen volume needed for a single surgical insemination. We have not found that following a surgical insemination with a vaginal or TCI breeding has increased the conception rate.
Frozen semen has the obvious benefit of being able to use a stud’s semen long after his death. International shipments of semen are frequently done with frozen semen because of long shipping times and quarantines needed for several countries. If you, as a breeder, are considering shipping semen out of the United States it is imperative to check prerequisite blood testing and the need for a physical examination with the frozen semen center before the semen is collected. If these requirements are not met the sample cannot be shipped.
Transcervical insemination is also used frequently for fresh semen breedings. TCI breeding method has shown to have a better conception rate than vaginal breeding and has not been shown to cause any increased incidence of uterine infection. Transcervical insemination gives the chance to evaluate the semen prior to breeding. TCI breeding has the added benefit of successful conceptions with semen of low numbers or a poor quality thaw that would not likely produce a litter from a natural or vaginal artificial insemination.
Multiple choices are available for breedings. With accurate ovulation timing and advances in semen handling and shipping, we have the ability to produce puppies from deceased males or males from a different location.