Dogs In Season

The estrus cycle commonly called heat is when the female dog is in its mating period. During this time the dog is called "in season" or "in heat". On the whole female dogs have heir first estrous cycle when they are between the ages of 6 - 12 months. The basic rule is the larger the breed the older the dog before its first estrous cycle. Therefore large breeds on the whole have their first estrus when they are 12 - 24 months.

The estrus cycle can be broken into two parts:
Proetrus: Vaginal bleeding occurs typically lasts roughly a week long give or take a few days. Increase swelling of the vulva leading to pressure on the bladder which causes an increase in urination. Male dogs will go mad for her but she will not mate with them yet.
Estrus: The female dog allows the male to mate and conception occurs. The vaginal discharge turns yellowy and less bloody. The part of the cycle can last from between 4 to 14 days.During this time the female will allow all males to breed with her.
There are two other stages called Matestrus and Anestrus that show no symptoms but false pregnancies happen at this time.

A dog is usually in season for around three weeks. It is common for a dog to be in season for between two to four weeks.
The most fertile time the dog is in season is right in the middle of the period. So if the dog is in heat for three weeks the middle week is when the dog is most fertile. Having said that a dog can get pregnant over the whole period while the dog is in season.

The most common cycle is twice yearly so every six months a female dog is in season. However, like everything there is a range between 4 to eight months a dog will regularly be in season.

As said before the female dog can get pregnant during any point when she is in season. This will be evident as the dog will allow males to mount her.

Spaying should be done as early as possible before the first season. Once you have decided that you don't want her to breed there is no point in waiting. Vets now spay as early as six weeks of age.
There are big health advantages to getting your dog spayed. It rules out contracting pyometra and metritis and there is a lower risk of getting a mammary tumour.
This is the best solution to prevent unwanted dog and overpopulation.

No. A dogs fertility is not comparable with humans. As a dog gets older her fertility declines but she can still get pregnant and produce more litters. To top this you must get your dog spayed.

No. In this way dogs compare with humans. The females follow the estrus cycle, get pregnant and produce litters the males only get the females pregnant.