Saturday, November 29, 2008


This article was written by Dr. Kitty Kenyon of Sanger CA. If you have any question you may call her at her clinic 559-875-2922 or email her at She has done a great job on Lucy with Frozen semen.


You’re a breeder and you want puppies from a stud far away or one who is dead but you’ve heard about all the failures. There are some things as a breeder that you can do to increase your chances of getting those puppies.

The first thing is to pick a veterinarian who has a special interest in reproduction. These vets should be up on the latest techniques.
Breedings done naturally or side by side AI with fresh semen are very forgiving. Fresh semen lives about 7 days in the uterus .So as long as you are not too late you will get puppies with a normal bitch. When we use fresh chilled or frozen semen there lies the problem. Fresh semen lives 48 to 72 hours and frozen for only 12 hours. Obviously you want the eggs there and ready when the sperm arrives. So timing is critical.
The bitch is unique in her reproductive physiology. Most of the other species ovulate in an estrogen environment whereas the bitch ovulates when progesterone levels are high. Another unique feature of the bitch is that the egg is not mature when it is ovulated. So in other species breeding and insemination coincide with ovulation, insemination of the bitch is performed 2 to 4 days after ovulation. In the bitch the critical timing events occur 4 to 6 days before optimal breeding times.
Ovulation timing is an art as well as a science. It is not a cookbook thing and you need a professional helping you who is well versed and willing to spend the time necessary to do it right. A number of tools are available to us. Estrogen is already low at the optimal time to breed so it is of no value. Vaginal cytology mimics estrogen levels so is a very marginal parameter in predicting breeding dates. Cytology can alert us to a vaginal infection and other things but not predicting breeding dates. Evaluation of external genetalia and behavior are also not reliable indicators for timing breedings.
The hormone LH (lutenizing hormone) is the biological trigger for the cascade of events that culminate in ovulation. This surge signals the transition from proestrus to estrus. Ovulation usually begins 2 days post LH surge. Ova mature 2 days later and remain fertile for 2 more days. Optimal breeding times are 4,5 and 6 days post LH surge. There is an in house test for the LH surge but LH is very short lived and the test needs to be run everyday. If feasible daily blood draws should be done the serum and be frozen so that a retrograde LH test can be run after the progesterone’s pin point the LH surge.
Progesterone’s initial rise occurs con comittently with the LH surge. Baseline levels will rise to 1.5 to 2.0 ng/ml. Ovulation occurs when progesterone levels rise to 4-10ng/ml. Most bitches ovulation occurs at 5 or 6ng/ml. It is important to start testing early enough to define a baseline usually at 5 days into the bitch’s cycle. Progesterone levels need to be measured by the RIA method. In house progesterone testing is not accurate enough for chilled or frozen breedings. Please remember this, I haave done comparisons of the in house test and the lab tests which give you an actual number and they just do not coincide. So do not waist you time or money.
In the normal bitch, it is recommended to start progesterone testing at day 5 in their cycle and to test every other day or 3rd day until ovaulation is confirmed. In a frozen breeding blood can be drawn and saved and a LH test run to confirm the LH surge. Breeders that are not willing to make this commitment probably should not bother with a chilled or frozen breeding. You spend all this money for semen and if the timing is off, you have just wasted your money.
Insemination of chilled semen can be vaginally, transcervical, or surgically implanted. Transcervical is not recommened for toy or giant breeds. Frozen semen should always be inseminated into the uterus via surgical or transcervical. Any older bitch or with semen of marginal quality needs to be inseminated surgically. One advantage of surgicval insemination is that the sinseminator can handle the uterus and pop any6 cysts that have formed which is common in older bitches. The cysts can cause the ova not to implant.
I hope this overview helps you to see the importance of timing. Veterinarians are not wizards, we need some hard parameters to time your breedings.

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