What is Artificial Insemination
The artificial insemination of dogs is nowadays an international hobby. There is an open transfer of information between countries due to kennel associations, magazines, the internet, and international judge exchange in dog shows. All this has increased the interest in international exchange of dog sperm, and in addition, posed new challenges for veterinarians in artificial insemination and the storing of sperm. Artificial insemination allows using the best possible male dog irrespective of distance, and time, since frozen sperm can be utilised decades after the death of the male dog.
One method of insemination is to infuse the specially prepared semen directly into the deep vaginal area of the bitch. The bitch then will be raised for a few minutes in an attempt to have gravity assist with the flow of the semen as deep into the vaginal area and as close to the cervix as possible. Then the bitch needs to be restricted with her movements for 6 to 8 hours after the insemination. The individual sperm cells need to pass through the cervix from the vagina and into the body of the uterus. From there, they get further up the two "Horns" of the uterus. At the end of the tubes the two ovaries are situated which produce eggs, the eggs travel through a tiny opening into the far end of each uterine horn. When the eggs go down the uterine horns they meet the sperm cells going up. There is a chance that the egg will be fertilized by some lucky sperm cell during that process.
The surgical implant is another method involving implanting the sperm directly into the body of the uterus. From start to finish, the surgical Artificial Insemination procedure takes only a few minutes. Light general anaesthesia is required. Absolute sterile procedure is an important factor. The frozen semen is thawed under the special requirements and then implanted into the female, as soon as she is ready. Although the bitch is awake and ready to go home in 30 minutes or so, some veternary practices prefer to keep them over night just to minitor the primary healing of the stiches and post-anaestatic reaction if any.
Prior to that a bitch comes into season... Vaginal cytology counts is performed beginning in most cases around the sixth to eighth day. (There is no need to panic before that time: if there is no blood on the 6th or 8th day, the bitch might just have a false heat, which is no good for breeding.) When the superficial vaginal cells become 80-90% cornified, then the blood progesterone hormone levels are tested. The most accurate result is given by Immulite 1000 and its modifications, the only blood testing system suitable for canine semen. These blood tests are performed every other day, or daily as needed to monitor the cycle, to detect the starting point of ovulation and to detect the optimal breeding time. Only when we reach this level of progesterone do we begin breeding the bitch. So it is all down to estimating the time for breeding or the suitable progesterone level. 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. No more than three tests are usually needed for a normally cycling bitch
At the moment numerous recent studies of progesterone have not agreed yet on one single range as a fool proof guide for inseminators. The ranges vary from centre to centre starting from 11ng/ml to 25 ng/ml. For breeders, pups are the only "statistical data’ they desire. Although we have worked out certain guidelines for reading the progesterone levels, we treat every patient individually, performing multiple blood tests and if possible multiple matings to achieve proper results.
Naturally, the level of progesterone for fresh AI and surgical implant are different because frozen sperm cells have had their natural abilities diminished, in a pelleted product. These sperm will only survive for 12 hours at best once inside the bitch. This is a remarkablly shorter period of time when compared to fresh semen which has been thought to survive for four to six days inside the bitch. The bottom line is that when frozen canine semen in pellets has higher percentages of live, progressively motile sperm cells. These sperm cells are healthier and are much more capable of crossing through the cervix, moving into the uterus and into the oviducts where fertilization occurs.