In order to maximise the odds of conception in the breeding bitch, it is worthwhile
to pinpoint the optimal moment for mating. Identifying the point of ovulation can improve reproductive success significantly. Additionally, an accurate ovulation date can help plan for whelping, as it usually occurs 61-65 days after ovulation (in 80% of cases).
Determining the Ovulation Period
Most mammals ovulate when the oestrogen level in the blood is increasing. Dogs, however, ovulate when the oestrogen level is declining and the progesterone level is increasing. Oestrogen levels can give us a general idea of when a dog will come into heat, but are not sufficient alone to determine when breeding should actually take place. Vaginal cytology (the microscopic examination of cells from the vagina by your veterinarian) can also provide some general information.
Being receptive to the male is a behavioural change that can occur during ovulation, however it is not a reliable one. Oestrous lasts seven days on average but can last anywhere from one to 10 days, and copulation during this time does not ensure it is the optimal time for mating.
Furthermore, many females allow copulation to occur when they are suffering from urinary infections or ovarian pathologies (such as ovarian cysts). Acceptance of copulation is not enough on its own, due to its unreliability
Many breeders organise systematic copulation 12 days after the first sign of bleeding, then two days later. With this method, 40% of females may be successful, however 10% are ready for mating before this time frame, and 50% ready for mating afterwards. With this method, there is a risk of having a poor success rate.
Lighter blood losses from the vulva after the initial discharge of blood, is generally a sign of the end of pro-oestrous, however it is not a reliable sign of oestrous.
A vaginal smear can be taken by a veterinarian and examined under a microscope. A smear can provide information on determining the time just before and just after ovulation. It can also detect any inflammation in the vagina. Although smears can provide useful information, they are not a precise method of detecting ovulation.
The blood progesterone level is the number one way to accurately determine the optimum timing of copulation. In dogs, the ovaries start releasing progesterone 48 hours prior to ovulation. Ovulation is associated with a rapid increase in blood progesterone. This can be measured by taking serial blood samples from the bitch by the veterinarian. Between two to five measurements are often sufficient to monitor standard oestrous. Once ovulation has been pinpointed based on blood progesterone, the optimal time for copulation is 24-48 hours after ovulation.
- Precisely determining the moment of ovulation and timing copulation, is associated with higher success rates.
- Ovulation occurs when oestrogen levels are declining and progesterone levels rapidly increase.
- Behavioural changes associated with ovulation in the bitch do occur but are not reliable.
- Vaginal cytology is performed by a veterinarian and can provide more information to the timing of ovulation.
- Serial blood progesterone measurements are the most accurate way of pinpointing ovulation in dogs.
Dog Breeding Guide, Royal Canin SAS, 2010