FRESH EXTENDED SEMEN BREEDING
Mary C. Wakeman, D.V.M.
Fresh extended semen (FES) is semen which is collected at the time it
is needed, for the purpose of being shipped. Frozen semen is semen which is collected
for the purpose of being stored over a period of time, or for being shipped
to distant places (for example Australia) where fresh semen would not arrive
soon enough to be in good condition. Actually it used to
be the case that even semen was quarantined upon arrival in Australia for
3 weeks. With the new canine quarantine laws at the present time, there
may be a less restrictive policy on semen as well.
Fresh extended semen is processed in a similar way to frozen in that
a ‘medium’ is used which protects and nourishes the sperm cells in transit.
However, the freezing is avoided, thus assuring in most cases an over 40%
better number of live and motile sperm cells. All extenders are not equal,
and those who wish to freeze or ship semen should carefully research the
subject, and not be swayed by advertising and other marketing techniques
in making their choice. With the best of extenders, we expect fresh extended
semen to be much more effective in fertilizing the bitch’s eggs than frozen
semen from the same dog would be.
There are various reasons for shipping semen instead of dogs. The possibility of death of the bitch due to shipping, for instance, as well as the stress which can precipitate herpes or bacterial infections and result in resorbtion of the fetuses. Sometimes the weather - hot or cold and snowy - is the reason to keep the bitch home. Sometimes holiday traffic. There stresses involved in shipping can be sufficient to prevent a litter being whelped, whether from Herpes or other factors.
As veterinarians in general become better at assisting breeders in the detection of the appropriate time to breed, the statistics for litters whelped from fresh extended semen will continuously improve. There are several ways of gaining information on timing breedings. The most important technique in timing estrous is a blood test called an "RIA progesterone". The RIA or radio-immunoassay gives us a real number, not a range such as the in-the-office ELIZA technique tests produce. Once we obtain a number from the RIA test it is frequently possible to extrapolate that number to determine the best day. Sometimes 2 or 3 RIAs are required. It is not possible to handle the information from the ELIZA tests in the same way.
The next best timing technique, of course, is the response of the dog and the bitch to each other; obviously, this important indicator won't be available to us in FES breedings. Vaginal cytology ("smears") performed routinely every other day from day 8 on will be useful in the hands of a veterinarian experienced in reproduction. An instrument ('Estron') is available which measures the electrical conductivity of the cervical mucous, which works quite well if done daily throughout the estrous cycle. LH and Progesterone ELIZA kits are available to help those veterinarians without skill in reading smears, or other diagnostic instruments, but are much less useful than the RIA progesterone performed at a lab. Since progesterone is not a species specific hormone, these RIA tests can even be performed at your local human lab in a pinch. I believe the most widely used progesterone ELIZA in-the-office kit is one which started out as a sheep test.
The method I generally find most useful and reliable for most routine matings is the endoscopic examination of the cervix, which changes in appearance according to a very reliable schedule. The reference for this technique is : NORMAL CANINE VAGINOSCOPY by F. Lindsay and P. Concannon, published on page 112 in SMALL ANIMAL REPRODUCTION AND INFERTILITY, Edited by Thomas J. Burke, 1986, Lea and Febiger. However, when we're shipping and timing of appointments, freight services, airline schedules and the availability of veterinarians and owners must all be taken into account, then we do the RIA test on day 8, scoping the bitch first to be sure we're in the right vicinity time-wise. We are available to the vets on the other end to help them understand the reasons for using this test, and for help in interpreting the result from the lab and making the extrapolation.
Whatever method used, skill in estimating the progress of the estrous cycle is the greatest asset in producing puppies from chilled semen. Without this skill, the fresh extended semen breedings, as well as any other kind of artificial insemination, is likely to fail. This being the case, the bitch owner may need to research the availability of veterinarians with these skills in their general area. They may find themselves traveling a good way to obtain this service.
For best results
I hope I have persuaded you to plan ahead, and begin working on your planned FES breeding a month ahead of the expected insemination date. Failure of a FES breeding, or live breeding for that matter, can occur for any number of reasons having their base in lack of preparation. The expense of the kits and shipping, the collection, processing and insemination may be in the same ballpark as shipping the bitch, depending on the size dog being shipped. But the cost of the procedure is not the main expense. The expenditure of good will and availability of both veterinarians and both dog breeders is the main cost. The main difficulty, after timing the bitch’s season, is obtaining this willing participation. Don’t let the breeding fail through lack of preparation!