"Three days! I have to stay here three more days?!" exclaimed the unbelieving Great Dane breeder who had driven non-stop from Washington state to San Diego, California with her in-season bitch. Based on a "reproduction veterinary expert’s" interpretation of a progesterone test, the breeder made a frantic 12 hour trip to the stud dog, only to have the bitch ferociously try to take the stud’s face off.
Breeding dogs is a serious commitment by conscientious dog owners. Normal life is suspended when a bitch comes into season. Vacation plans are put on hold, excuses are made to bosses, weddings and anniversary parties are changed, and even elective surgery is rescheduled. Such is the importance placed on breeding the bitch. So it is never a surprise when I get emergency calls from breeders.
The Great Dane stud owner had changed weekend show travel plans to accommodate this bitch when the Washington veterinarian said the bitch was ready NOW. Yet, the progesterone test I performed showed the bitch would not be ready for 60 hours or more. The same bitch, 58 hours later, standing steady, bred without any fuss. A fine litter resulted.
Unfortunately this scenario is not infrequent at our Canine Cryobank laboratory. This has held true now and in years past, when vaginal smears were the only veterinary hint at timing the breeding.
Years ago, in our West Los Angeles office, we were called in at 12 midnight because a veterinarian in Davis, California has done one vaginal smear that morning and insisted the bitch be bred immediately. The bitch was flown down by private jet and the stud greeted her happily, but did not show any interest in breeding. Another vaginal smear showed the bitch had 100% intermediate cells, but no superficial (cornified) cells. One week later, she too bred naturally.
Interpretation of vaginal smears relies on the technical staff’s experience in properly preparing the specimens and most importantly, reading hundreds of vaginal smear series of bitches’ seasons. Over and over in lectures to veterinarians and breeders, we emphasize that reading ONE smear is useless to time the breeding. When progesterone testing became available it was hoped that by removing the need for extensive experiential interpretive skill, the breeders would be better served. However, progesterone testing requires careful attention to laboratory techniques and awareness of current test kits’ reliability.
Progesterone is a hormone measurable in the blood of the estrus bitch. Progesterone rises after the luteinizing hormone peaks and continues to rise whether the bitch is bred or not, pregnant or not for the next 60 days or so. Therefore, it is a wonderful tool for the breeder to determine breeding dates. Bitches are best bred when the progesterone is 9.5 through 10ng/ml by our test. No more than three tests are usually needed for a normally cycling bitch.
Occasionally veterinary laboratories will offer progesterone testing by radioimmune assay and the results will have a quantitative value, i.e. a numerical value. Several marketing companies have put progesterone kits on the market for in-house use; some are no longer made, some are marketed under different names. The kits use monoclonal antibody techniques to give a range as a result, i.e. below baseline; between 2ng/ml to 5ng/ml; over 7ng/ml, for example. It was one of these $100.00 in-house kits that was responsible for the Great Dane’s Washington to California trek. Only one in-house kit tested in our laboratory was reliable. This imported kit is used by Greyhound stud farms with incredibly reliable results for natural, cooled, and frozen litters. (Camelot Farms, College Station, Texas).
Our laboratory uses an Enzyme Immune Assay kit of analytical laboratory quality, imported from France. The kit requires a spectrophotometer, laboratory quality pipettes, and printer for an investment of $10,000.
Reliability of test results relies on proper sampling techniques and proper attention to test kit preparation. The kits must be at room temperature. The kits have a definite shelf life which must be careful monitored. The timed reading of results is very, very important. If the kit instructions say the results should be read in five minutes, any results later than that are suspicious.
In our laboratory every effort is made to assure reliable results.The kits are taken out of refrigeration at the same time every morning. The pipettes are quantified every morning. A timer is used on every phase. The same amount of blood is always drawn in the same size syringe with the same amount of heparin used to rinse the syringe and needle. The blood is centrifuged immediately and clear plasma used for the test. Over the eight years and thousands of progesterone tests performed, the EIA is remarkably reliable. The recommendations we make to breeders are based on the experience with the testing method we use. Years ago, a researcher from Cornell announced that bitches ovulate at 4.77 ng/ml progesterone. Using that published data we had terrible conception rates. Later, it was noted that the ovulation value was only a statistical determination. For our clients, pups are the only "statistical data’ they desire. The kit we use was developed and tested on breeding canines, an important background fact when it is noted that several in-house progesterone kits were actually produced for the equine market.
WHAT BREEDERS NEED TO KNOW ABOUT PROGESTERONE TESTING
Ch. Kismet's a Walk in the Clouds
