This article is from the rec.pets.dogs: Breeding Your Dog, posted to rec.pets.dogs newsgroup. Maintained by Cindy Tittle Moore with numerous contributions by others.
You must make sure the bitch and the stud both are free from brucellosis before breeding them. Brucellosis causes eventual sterility in both sexes (sometimes non-obviously) and can cause a litter of puppies to be aborted or die shortly after birth. In addition, brucellosis is on occasion transmissible to humans via the urine or feces of an affected dog. Between dogs, it is most commonly passed in sexual intercourse, although an entire kennel can be infected through contact with secretions.
The sire should be in excellent general health. The dam _must_ be in good health, to withstand the stresses and rigors of a pregnancy. They must both be up to date on their vaccinations.