AI techniques used at our practice include vaginal insemination via pipette, transcervical insemination (TCI) using an endoscope, and surgical insemination. We like to choose a technique which maximizes the probability of pregnancy, while minimizing risk to the bitch and cost to the client. All three techniques are ideally used with proper ovulation timing.
Good quality fresh semen is generally inseminated vaginally via a pipette. Sub-fertile semen or fresh-chilled semen are best deposited directly in the uterus via TCI or surgical insemination. They may be deposited vaginally, but the pregnancy rate will be <65% due to the decreased quality of the semen. Uterine insemination increases the pregnancy rate to about 85%.
Frozen semen must be deposited in the uterus via TCI or surgical insemination. Vaginal insemination will lead to a pregnancy rate <25% due to the compromised function of frozen sperm. Uterine insemination of frozen semen also has a general success rate of about 85%.
The best time to breed depends on the day of the initial rise (when the progesterone level starts to steadily climb), the day of ovulation (when the progesterone passes 5.0), and the shape of the individual’s progesterone graph over time.
Simply put, a single breeding with fresh or fresh-chilled semen is ideally performed 48 hours after ovulation, and two breedings are ideally performed 24 & 72 hours post-ovulation. Frozen semen is deposited as late as possible before the end of the fertile period, ideally about 72 hours after ovulation.
The “art” of ovulation timing comes in dealing with deviations from the textbook case. For example, we have followed cycles with 10 days between an apparent initial rise and ovulation (the actual initial rise may be 1.5 or it may be as high as 3.5 or 4.0). We have also followed cycles with only 72 hours between the initial rise and the end of the fertile period (progesterone can go from 2.5 to 25 in 3 days, for instance). Knowing the date of the initial rise, watching for a particular range of progesterone values (based on type of semen and number of inseminations), and vaginoscopy are all factors we look at in deciding the best day(s) on which to inseminate your bitch.