Bitches in Heat
Some bitches stay in heat almost continuously, and although bred, do not become pregnant. This condition, called nymphomania, requires the attention of a veterinarian. After a slight operation the bitch comes back to normal almost at once; about a month later she has a natural return of heat and may be bred.
The first heat may be almost unnoticeable if you are not accustomed to noting the signs, though usually there is no mistaking it, particularly if any dogs are close by. The vulva becomes enlarged and there is a discharge, straw colored at first. This later becomes red, because of the blood in it, and again becomes straw colored as the period draws to an end. This discharge will probably continue for about nine days; mating may be carried out during the latter part, though most breeders prefer to wait until it has stopped. It must be done immediately after this has taken place, however, or you stand a good chance of missing the heat. It is usual to breed about the tenth to fourteenth day, but if the bitch has a bloody discharge far into her period, the time will be later. Breeding early or late has no effect on the number or type of the puppies, but its action on the sex of the young is a question which I have heard discussed by various breeders. Some claim that breeding early in the period produces more females.
During the time when the vulva is swollen, the bitch should be closely confined to prevent her from escaping and becoming involved with a dog not of your choosing. I have had a bitch go through a glass window-pane at this time and I have seen one climb a fence many times her own height or chew through a bench chain in her eagerness to get away. If your kennel happens to be two stories in height, it is a good plan to keep the bitches in heat on the top floor. This not only makes it a lot harder for them to get away, but it also prevents stray dogs from tracing the scent to its source.
However, should a bitch escape and become bred to a mongrel or a dog of another breed, this will not affect her or her future litters. At one time breeders had the idea that such a mismating would spoil the bitch for future production, but this is not the case. It has no effect whatever on more than the one litter.
Never breed a bitch on the first heat unless she is exceptionally late in arriving at this stage. In some of the larger breeds it is best to wait until the third heat. In any case, the bitch should have reached maturity before she is asked to assume the duties of motherhood. Do not throw this added strain on her when she needs all her strength for her own development.