Ovulation Timing and Breeding Management in Dogs
Ovulation timing is important when artificial insemination (AI) techniques are used because shipped, frozen, or chilled semen have decreased survival times. Survival time is only a few days for chilled/shipped semen and as low as 12 hours for frozen semen, in contrast to fresh semen that can live for 5-9 days. Several techniques are employed to maximize conception rates and litter size when insemination techniques are used.
Day 1 of proestrus is considered the first day that any signs of heat (estrus) are noted, such as vulvar swelling or vulvar discharge. Record this day on your calendar. It is recommended to schedule your first appointment for ovulation timing three to five days after the onset of proestrus. At this visit, vaginal cytology is utilized to guide when progesterone testing should be started along with previous history and clinical signs.
Vaginal cytology is used to determine the stage of the estrous cycle in order to pinpoint estrus, and is often combined with progesterone testing to determine ideal time for progesterone sampling. It may also be continued to determine when the first days of diestrus has occurred.
Vaginoscopy (examination with a viewing scope) can be used to evaluate changes within the vaginal vault that occur with proestrus and estrus. It is also performed with transcervical AI or when abnormal discharges are noted.
A digital vaginal exam is also important to evaluate for any abnormalities that may interfere with natural mating or whelping of the puppies.
Progesterone testing requires sending a blood sample to a referral laboratory or utilizing a quantitative in-house machine. The at home tests are generally not accurate enough to use reliably for artificial insemination when limited breedings are available or timing needs to be precise for ship chilled or frozen semen breedings or scheduled C-sections. Progesterone samples are generally submitted every other day until ovulation occurs, which is usually at a progesterone level of above 4-5 ng/ml that has increased >3ng/mL over 24hrs. Depending upon the time of sampling, results are available within 12-24 hours.
Once ovulation has occurred, insemination is planned for 2, 3, and/or 4 days later as it takes 2 days for the eggs to mature and be ready to be fertilized. If a second breeding is planned, it is generally done 24-48 hours after the first breeding. A progesterone sample is taken at the time of breeding to ensure levels are above 5 ng/ml (often between 15-25ng/mL).
In some circumstances, LH testing may be recommended. This is an important hormone that is released from the pituitary gland (in the brain) and stimulates the ovaries to ovulate. It is highly recommended to utilize LH testing when planning a frozen semen breeding. In some dogs, LH release is very quick (12-24hrs), and as a result, daily blood sampling may be required in order to identify the day of the LH peak.
For more information about the best options for your exciting breeding plans, please schedule a pre-breeding appointment with our reproductive team. We look forward to assisting you with your exciting breeding plans!