Now that we have documented the pertinent discussions pertaining to the roles, prerequisites and expectations of the brood bitch and the stud dog, we can proceed with answers to the salient question of when to breed.
This is not a straightforward issue. We must first of all understand the estrus cycle (when and for how long the female dog is in heat). Not understanding this heat cycle is perhaps the most common cause of an unsuccessful mating. Some ‘breeders,’ because of their lack of technical knowledge/experience, just simply put their dogs together at the wrong time. So let’s discuss this estrus cycle in some detail.
Firstly, let us understand that the female dog could show the first signs of heat (estrus) as early as eight months of age. Usually, the first ‘heat‘ appears when she is about 10 months old. There are no fixed times; just as a woman can be pregnant for 8½ months, 8 ¾ months, 9 months, 9½ months, etc, before delivery. We are dealing with biology and not the exact science of mathematics.
Secondly, unlike what the general feeling is, a bitch only comes in heat about twice a year (again, this can vary), but I have known bitches to come into heat every 4 months or so. This, however, is the great exception. I will now rely on a very adequate and simple text put together by Drs Carlson and Giffin on this subject.
As a general rule, estrus, the season of heat, lasts 21 days, as reckoned from the first sign of vaginal bleeding. The onset of heat (called proestrus) lasts six to nine days. A dark bloody discharge and firm swelling of the vulva signal it. It is during this stage that the female begins to attract the male who is able to detect chemical substances, called pheromones, which are discharged from her vulva and excreted in her urine.
During this preovulatory (before the eggs are released from the ovary) phase in the heat cycle, the female will not accept the male. If mating is attempted, she will jump away, sit down, growl or snap at the male to drive him away.
The second phase of the estrus cycle is called true estrus or standing heat. It is the time during which the female is receptive. She begins to flirt with the male, raises her tail and flags it to the side, lifts her pelvis and presents her vulva when touched in the rear. The vulva softens and the discharge becomes watermelon coloured or pinkish.
A microscopic examination of the vaginal secretions at this time will show a marked reduction in the number of red cells. A few white cells will be seen. Also, there are changes in the appearance of the surface cells of the vaginal lining. These changes enable a veterinarian to determine whether the bitch is ready to be bred.
There is another test for ovulation, which utilizes a paper strip to test the mucus from the cervix of the uterus. This is the same sugar test tape used by diabetics to check for sugar in the urine. The test is based on the fact that sugar appears in the mucus of the cervix when the bitch begins to ovulate. Insert the paper strip into the vagina near the cervix and leave it for one minute. Then remove it and read the colour. A negative sugar test suggests that the bitch is not ovulating. However, a positive test may be a false positive if a vaginal infection is present. This test is not as predictable as a vaginal cell test mentioned above.
Estrus, or standing heat, lasts 6 to 12 days. It ends when the female refuses to stand for the male.
The third phase in the productive cycle is called metestrus. It begins when the female refuses to stand for the male and lasts through the period of uterine repair (about 60 to 105 days). After a bitch has gone into heat once, her breasts and vulva will remain slightly larger than before.
The fourth phase of the reproductive cycle, called anestrus, is a period of reproductive rest. It lasts 100 to 105 days. The heat period usually comes every six to eight months. However, as I have said earlier, some bitches go into heat every four months and others only once a year. Several factors, such as the time of year, hereditary tendencies and emotional states, have a bearing. Some of these will be discussed when we write about infertility.