Dog Owners Guide To The Canine Heat Cycle

The canine heat cycle will affect female dogs that have not been spayed (neutered). The duration and age that female dogs come into Estrus can depend on the breed of dog that you own and on each individual dog (as each dog is different).

The period that your dog will be in heat can vary but will normally last from approximately 12 to 21 days. Each female dog will have two heat cycles a year (every six months). The actual period of time that your dog is able to mate during this time frame is about 3 days. There are some misunderstandings about the abilty of young dogs to get pregnant during their first ‘heat’ and yes it is possible for a dog or puppy to get pregnant during the first estrus – but it is not recommended as some breeds can have their very first estrus as young as 5 months and a puppy at this age is not fully mature and is not ready to be pregnant.

Although the canine heat cycle can start as early as 5 months it can also start allot later in larger breeds with some not coming into estrus until they are 12 months of age (or even older with giant dog breeds).

What are the symptoms of the canine heat cycle

When a female dog is going into heat (estrus) she will start to pay more attention to her vulva – she will probably start licking it and just being more aware of it (it will be swollen). The vulva is the area around the vagina and in the early stages of estrus it will be quite hard but as the cycle develops it will soften as your dog’s progesterone levels start to increase – your dog will also start to release eggs from her ovaries.

Your dog’s vulva might also start to bleed (the blood will be darker in color). The bleeding can be fairly intense (heavy) during the first few days of estrus but will normally decrease over the next few weeks.

Pay close attention to the color of the blood during your dog’s heat cycle because as the cycle develops the color of the blood will be less dark and will be more of a salmon color.

As your dog starts to get closer to the period when she is ready to mate she will start urinating more often to spread her scent and may curl her tail over to one side. You might notice that your dog’s urine has a much stronger smell during the heat cycle.

Just like in humans it is not unusual for your female dog to show some behavioral changes during the heat cycle after all her hormones will be all over the place – so she might want to spend more time with you or be a little clingy. Your dog might also be depressed or just seem out of sorts.

Controlling the heat cycle in dogs

Some experts argue that it is important that owners should control the heat cycle in their dogs whether this is through surgery (neutering) or other methods. The reasons for this are because…

1. It gives your dog a better chance of having better health – mainly because it can stop your female dog from getting mammary tumours, experiencing a false pregnancy and stop the chances of uterine problems.

2. Of course it can stop the obvious i.e. from your dog becoming pregnant.

3. It can stop your dog from experiencing changes in her behavior (that may upset your dog) and from unpleasant bleeding and physical changes.

It is important to mention that the use of sprays and lotions to try and disguise your dog’s odour during the heat cycle do not work – and male dogs will still be able to pick up the scent. The use of Chlorophyll and other tablets designed to eliminate your females odor during estrus also do not work. The only effective method to control the canine heat cycle is by having your dog neutered.

If you think that your dog is in heat then you need to make sure that she is well away from any male dogs – when we say keep her well away – a male dog that has caught the scent of a dog in heat will jump fences to get at your pooch.

During the canine heat cycle it is not a good idea to walk her in areas where she could come into contact with other male dogs as they will approach your dog and this could cause problems i.e. the male may attempt to mount your dog.

It is also possible (but uncommon) for a female dog in heat to also fight with other females if they come into contact during a walk or when out and about.

Below is a complete guide to your dog’s heat cycle

The heat cycle will normally occur twice a year but this can be variable. In fact some of the larger breeds may only have a cycle once every nine months. There are several stages involved with the heat cycle starting with the Proestrus stage. This will be followed by the Estrus stage and then the Luteal (Diestrus) stage. The final stage in the female heat cycle is the Anestrus stage. Below we have gone into a little more detail regarding each stage.


This is the first phase in the female heat cycle and will lead to the the female’s vulva becoming red, firm and swollen. There may also be some vaginal bloody discharge. The female will also start to release pheromones which are secreted to attract males. However, she will not yet be receptive to males and will not allow them to mount her. In fact if any male does attempt to mount her she may become snappy. The proestrus stage will normally last around nine days although this can vary from dog to dog.

Most breeders recommend that owners breed their dog from nine, eleven and thirteen days after the vaginal bleeding starts. However, this can be a difficult thing to judge as somes bleed very little while others have allot of vaginal bleeding.


The next stage in the heat cycle is the Estrus phase. During this stage in the cycle the female will allow males to mount her. This stage can last as long as twenty days but will normally be more shorter (around seven to nine days). The female may even start to raise her tail exposing her vulva to interested males. There will still be some bloody discharge but the blood will be a much paler pink in color.


During this stage in the heat cycle the female will either become pregnant or not. During this phase a very strange and unusual condition can occur known as a False pregnancy. This can lead to the female displaying all the symptoms of being pregnant without actually being pregnant. The Luteal stage is also known as Diestrus.


 This is the stage between the end of the Luteal phase and the beginning of a new Proestrus cycle. This stage will normally last from anywhere from two to eight months.

Did you know?

If your dog starts vomiting, appears lethargic or you notice that there is a greenish discharge from the vulva then she may be experiencing a potentially fatal condition known as Pyometra.

If you found this page particularly useful you may be interested in taking a look at our page devoted to the gestation period as it goes into more detail regarding each stage of the female heat cycle.

Did you know?

Although calcium should play an important role in your pregnant dog’s diet if you give your dog too much calcium it can lead to a very serious condition called Eclampsia. The reason for this is that by giving your dog too much calcium in the form of supplements this can disrupt how the dog’s body regulates the calcium levels.

Sometimes dogs are unable to give birth naturally so may have to have a C-section (also known as a Cesarean)). Some breeds including Bulldogs need to have this procedure because the puppies have such large heads.

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