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Dog Breeding: Medical Needs Your Dogs May Have When Breeding
Radiographs of your pregnant dog's hips and elbows should be made several months prior to her breeding. The veterinarian should give her at this time a complete physical in reference to her future breeding. An unvaccinated female dog, or one with an extremely low immunity, may respond well to inoculations she may need at this time; a substantial increase in colostral immunity is also provided to her puppies. The dam should be in a peak physical condition, neither under nor overweight at the time of a breeding.
Don't Forget The Stud Dog
A wide variety of factors can impact sperm. As a result, the stud dog should also be radiographed at least six weeks prior to the time of breeding. Normal, healthy sperm, resembling a pollywog in its early stages, is composed of a head and a tail. A sperm's structure is delicate, easily altered by chemicals, heat and recent illnesses. Factors affecting the viability of sperm may result in spermatozoa appearing with two heads, two tails, missing heads or tails or deformed heads and tails.
Deformed sperm are incapable of penetrating an egg's wall to form a zygote. Immature males and those recently physically ill may not have healthy sperm production, or may have a low sperm count. Ideally, therefore, only males in peak physical condition should be bred. They may be bred on alternate days over an extended time period to successfully produce viable sperm on each occasion.
The sex of each puppy is determined by the sire's sperm. The dam determines the number of puppies that can be conceived by the amount of eggs she releases during ovulation. Studies have reported healthy sperm remaining viable within a "friendly" (normal and not infected) uterus for as long as six days.
Breedings should optimally occur every other day during the female's full estrous period, in order to allow the stud sound opportunity to recuperate and rebuild a strong viable sperm "bank."
When Conception Occurs
The conception of a puppy occurs when a zygote is formed at the time a spermatozoa penetrates an egg's wall. Fertilization of the eggs occurs in the oviduct. It is at this moment of conception that a puppy's genetic makeup is set for life. From this moment onward, a breeder may only support the litter by offering the optimum environment, first for the dam and later for the puppies themselves.
Once fertilized, the zygote descends into the uterine horn's lumen. There, it "floats" unattached while being nourished by "uterine milk" for approximately 18 to 20 days before actually becoming implanted in the uterine wall. The formation and attachment of canine placenta is not unlike the processes found in other carnivores.
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