Dogs accomplish mating in a unique physical way and process. In the dog’s penis, there is a bone. It is thick at the base and tapers toward the point. Through it runs the urethra. The penis is of a spongy tissue which, when an exit valve in a large vein is closed, fills with blood under pressure from a large artery. Right behind the bone, there is an amplexus of nerves that is very sensitive. Pressure on this point causes a violent thrust reflex. At the same time, the valve regulating the exit of the blood from the penis closes and the dog develops an erection, which is a distension of the penis with blood.
Unlike the penis of any other group of dogs, the canid’s penis has a large bulbous enlargement at the base. When the dog’s penis enters the vagina of the bitch, it must go through a muscular ring or constriction of the external opening of the vagina. The bitch must elevate the vulva to make a straight tube of the vagina. As soon as the penis is pressed through this restricted opening, it passes into the vagina, which is much larger and very elastic. The moment the penis is through, the pressure of the tube on the reflex nerve center causes a violent thrust and the dog clings to the bitch with all his strength. And at that moment the penis swells to large proportions, three times its normal diameter in the smaller part and five or six times at the bulb. The swelling of the bulb prevents the dog from withdrawing his penis. At this time he ejaculates semen and the sperm it contains. Pressure is built up and the semen is forced through the cervix and up the horns of the uterus, through the fallopian tubes, and into the capsule which surrounds the ovaries. In twenty minutes after copulation starts, the tensest will have ascended that far.
Dogs remain hung in this manner from one minute to two hours. The average time is slightly less than twenty minutes. The male turns around and faces the opposite direction from the bitch. While the two are hung in this manner, they may get their nails into the dirt and pull with far more than their weights. No one should be alarmed when they pull this way; neither dog is being hurt. As the valve relaxes, the blood leaves the penis, usually from the bulb part first, and allows the enlarged penis to slip out.
There have been many instances where a pair of dogs have been raised together, in the same home, and the owner has wanted puppies from the pair. While the bitch seemed to be willing to mate, the male showed no inclination. Then, toward the very end of the acceptance period, the owner has found them copulating, and good-sized litters of puppies have resulted.
Some dogs are never willing to mate more than every other day if left alone with bitches in the acceptance period.
Some females are very selective about the male they mate with, while others will accept all corners. After repeated unsuccessful attempts to mate to a selected stud, a female may permit the neighbor’s mongrel the privilege.
Before breeding it is wise to have a veterinarian examine a female to be sure she is in good health and has a normal pelvic opening for the breed or type. If she has a small pelvic opening she may require a cesarean section, which might influence your decision to breed.
It is also helpful to phone your veterinarian a few days before the impending delivery date to alert him.
Normal Mating: Watch first for swelling of the female’s vulva and then for the first day of bleeding, which you record as day one for future reference. You observe the vaginal discharge change from bright red blood gradually to a faintly pinkish straw color by about the eighth day. If the stud is readily available, try the first exposure on the ninth day. If mating takes place permit them to breed every other day thereafter until she refuses him.
On palpating the vulva it will be firm until quite suddenly it loses this firmness and undergoes a detumescence and becomes somewhat flabby. This is the time to breed if you plan only one mating. Slightly before and during the acceptance period the bitch is said to flag. The term flagging refers to a bitch in heat twisting her tail to one side when she is receptive and when either the male is smelling and licking her or even when a hand is rubbed over her hips on either side of the tail. And when she does permit the male to try, she flips her tailor flags to remove the tail from her vulva for mating.
When two willing dogs try repeatedly without the male gaining entry, the following is a proven method of success. With the male mounted on the female and you kneeling on the left side of the animal, gently grasp the male’s penis so that the thumb and index finger are on either side behind the bulb of the penis. With the left hand reaching over the male’s back hold the vulva so that the penis in the right hand can be directed into the vulva in the left hand. When you gently squeeze with the thumb and index fingers of the right hand, the male will thrust with a reflex action and gain entry into the vagina, where the bulb distends and the tie is accomplished.
The most common problem is the female who tries to bite the male when he makes advances. Even when muzzled she becomes so violent she must either be raped or artificially inseminated.
When normal mating cannot be accomplished it may be that the bitch is not ready to breed or has passed her acceptance period. In either case, she is unlikely to conceive by rape or artificial breeding. A bitch may have a vaginal opening inadequate to accept the male. Or she may have a structural weakness that causes her to collapse with the weight of the male. She may also have a false heat: she will have normal signs of bleeding and swelling but not as pronounced as with a normal heat. Moreover, she is not as receptive to a male. As she does not ovulate, neither normal nor artificial breeding will produce pops.
All too often a prized show bitch will be shipped a thousand miles to be bred to a famous stud only to come into a normal heat two months later. Although there are many tests to determine the proper time to breed a bitch, the only one worth much is that performed by a veterinarian. Vaginal material is stained and studied under a microscope; at ovulation, cell changes are observed that indicate the proper time for orating. A female usually ovulates at the same time in subsequent heat periods.
Of course, a problem in accomplishing a mating may be due to the male. He may have weak hindquarters or he may have infections that dampen his desire and prevent the act. Or, in the presence of strangers, he may not even try. Some males have a web or tendon-like tissue from the tip of the penis back up the sheath that causes great discomfort with an erection. This web may be snipped to correct the problem. Some breeders have had their bitches artificially inseminated for so many generations some of their offspring seem to lose the sex drive. There are few redeeming features of and few cases in which artificial insemination can be justified. When performed properly on dogs that have been produced from natural mating the success rate is almost as good.
But owners usually request help when help is not in the best interest of future generations. One exception may be the selective bitch that will permit only a male of her liking to mate with her. The neighbor’s mutt passes muster but not the famous international champion you would like to sire her puppies. Another possible acceptance situation for artificial breeding is when dogs are virgins. It is always wise to mate a virgin bitch with a male that has had at least one mating experience before or to use a virgin male only when the female has had a successful orating previously.
After the female’s ova have been fertilized, they nest against the uterine wall. As they grow, each fetus is surrounded by amniotic fluid which is enclosed in an amniotic sac. Each has a placenta attached to the lining of the uterus from which nourishment is carried to the fetus through the navel.
It is difficult to predict the size of a litter from the appearance of a pregnant dog. If she is very large, it may mean that she is carrying a small litter of large young or that she is carrying a large litter of small young. X-rays are the only dependable means of determining the number, and they are easily employed if advisable.
See more: Dog Cough