The dog heat cycle (estrus cycle)

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For several different reasons some owners may not want their female dogs to get spayed. For the owner of such an “intact” female some knowledge about the heat cycle is helpful to prevent “accidents”. In this post you will find information on the heat cycle in dogs, signs to look out for and measures to take.

In this relating article I am introducing a neat way to keep the bloody messes under control during your dog’s heat – with the dog heat suit

The dog heat cycle (estrus cycle)

First and foremost it is important to note, that dogs are very different and that there is NO rule of thumb valid for EVERY dog, when it comes to heat cycles, especially regarding length and signs.
As pet owners our best bet is to rely on our personal perception of our dogs and changes in their moods or bodies – rather than just looking for discharge etc.

Steve Gogulski, breeder and owner of assisted me with answering some interesting questions to be found in this essay, offering more detailed insight into the heat cycle in dogs from a professional perspective.

www.bullterrierfun.comBTF: “Steve, one of the most common questions owners have is probably “How often will my female come into heat?”. Are there any statistic numbers?”



bullterriersofnc.comSteve Gogulski: “The problem with answering this question is the fact that no two females are the same and heat cycles can change depending on age, whether they are being bred, other females they are around which come into heat, health, activity level, etc.”



The main and important period of a heat cycle in dogs lasts about three weeks. During this time the dog undergoes three different stages, followed by a fourth “resting” stage:

Stage 1 – Proestrus

Proestrus is a non-fertile stage. Bleeding may or may not occur depending on the individual dog. Some dogs experience almost “silent’ heats, while others do bleed a lot. The proestrus usually lasts about nine days* (but that can vary!).
This stage is marked by an increase in the female’s estrogen level (can only be accurately determined by testing). The dog is not receptive to males yet, but from now forward she will more or less obviously show many of the signs of heat. Possible signs are moody days, swollen teats and/ or vulva and/or having to “go” more often. Females in heat naturally understand that marking their scent during urination in several areas outside will attract males that will easily and instinctively pick up the scent of a female in heat thus the desire for them to use the bathroom outside more often.
In many dogs it is hard to rely on the occurrence of bloody discharges alone, as they may differ a lot!
But every owner who knows their dog’s behavior quite well will notice other mentioned changes (explained in more detail below).

Another significant sign are males becoming more interested in your female.
If you notice males becoming interested or your female is showing the signs of entering her heat , you should avoid all contact (not only mounting, but also the dogs’ rears touching etc.) between your female dog and males. The reason is that mounting is not mandatory to introduce semen in the right places and that semen can survive for about a week under the right circumstances. If your female catches semen while non-fertile, but then becomes fertile while the semen is still alive, chances are she could still become impregnated. Females have become pregnant while being completely separated in a kennel run from males. Even with a kennel or chain link fence separating a male and female, conception can occur. This is often when you hear about an owner explaining that they think a neighbor’s dog jumped over their fence and bred to their female which resulted in pregnancy. Rarely those are owners aware of the fact that leaving their female to roam free in their fenced in yard has probably attracted every intact male on the block, which are said to have the ability to pick up the scent of a female in heat for up 3 miles and may have resulted in a pregnancy through the fence.

Read on about Phase 2, the Estrus, on the next page.

10 thoughts on “The dog heat cycle (estrus cycle)

  1. Hi
    My puppy Arna come into her first session on the 24th September 2016 and has only stopped bleed for 4 days since then, she humps her bed so I take it away from her, she seems fine in herself, but a few weeks ago she got a bad tummy upset and had to stay at vets, for the day, she now growls in her sleep and in the evenings, she is very friendly with other dogs she meets and people, I have had several tests done on her and nothing shows as being wrong, she is deaf in one ear so I was going to get her spad. Has anyone else had this problem with there bitch

    • Hello Sonja,
      I am afraid, I can’t really figure out the core problem you are seeking answers for. You seem to be dealing with different issues. Which one is the problem you are trying to resolve? Is it the humping or the growling or the question, if having her fixed would be a good idea or not?
      Once I know what exactly is bothering you, I will be happy to provide advice.

  2. Hi I have a female bull terrier that will be one year old in February she started bleeding and has been bleeding for over a week I was wondering how long do they bleed, i feel bad since i have her in her crate all day other than letting her out to use the bathroom or somedays outside her kennel.

    • Hello Jenn,
      in my experience heat cycles are really different with every single bitch and the bleeding can last up to three weeks.
      During that time you should remove valuable floor coverings, if possible and use towels and blankets to cover places the dog is using (sofa etc.). Also you can limit the dog’s access to certain areas. But it is never a good idea to crate this breed – or actually any dog – for longer periods of time, just because they are messy. Bull Terriers easily get bored and tend to develop obsessive and self-destructive disorders, when crated or kept on short leash without entertainment for longer periods of time (that can even be just a few hours). And that can lead to a whole bouquet of other problems that are much harder to deal with than just a few blood stains.

      There is a very good cleaner available – I am using it all the time – they have different varieties for different problems:
      Nature’s Miracle Stain & Odor Remover
      It does not only remove stains, but also neutralizes odors. That stuff works wonders!

      To reduce messes when my girl is in a heat cycle, I am putting her in a suit. I wrote an entire essay about it, because I am thrilled by this product, you’ll find it here:

      The Suitical Recovery Suit for Dogs was originally invented for dogs after surgery.

      But it really does a great job during a heat cycle also! I can even let my dog sleep with us in bed, because it works like a romper on a toddler – no messes!
      I hope this info helps. Please feel free to ask more questions anytime.


  3. My female was in heat in december 2016,her heats r 7 months apart. Shouldn’t she be in heat now?on july 11 she had a few drops tgat lasted about 3 days..i was hoping to breed her again this cycle..she is a siberian husky

    • Hello Dianna
      Usually, I am more than happy to provide advice. But in this situation, I think a vet visit or a test kit is well warranted. Because the best way to find out what is going on is to have an ovulation test performed on the dog, especially if you intend to breed her. Dog’s cycles can vary and even be completely irregular. If you have read the essay you’ve commented on, you already know that blood is not a very reliable indicator for the dog being in its fertile phase.
      A vet can also test for other breed specific issues and tell you if your dog does bring the right genetic conditions for breeding.

    • Romano,
      if you referring to your dog’s vulva noticeable swelling is quite possible and normal. If it’s only swelling and she does not seem to feel uneasy or sick in any way, I would probably not be worried.
      Her teats could also be swollen already, but usually this happens a few months later, about the time when the dog would be wet-nursing her offspring. That is usually the time when the teats grow larger in some bitches – pregnant or not. A few weeks after the heat a false pregnancy could occur as well and contribute to even more swelling. Even a little lactation can happen. Going back to normal for the teats could take a while. With my girl it always takes months.
      If there’s anything you really worry about, buy yourself some peace of mind and let a vet take a look at it. He will also be able to give you some expert advice.

  4. Hi I have a bull terrier cross staffy she is 6 months and I want to get her desexed before her first cycle. I know they say that they can get their first cycle from 6 months on but I’m just wondering if you have a rough idea of when that might be. Thanks

    • Hi Michelle,
      I really think this is the perfect topic to discuss with your vet during the next routine exam or so. I am not able to give advice from a medical perspective, simply due to lack of experience. I am actually strongly opposed to spaying/neutering. My girl is 4 years old now and still intact. During my life with dogs I had to deal with the issue only once when my last Bull Terrier was suffering from a life threatening infection and the only way to save her life was to surgically remove her entire womb.

      I will not try and talk you out of your plan because I believe that everyone has to make their own decisions based on conviction and circumstances in life.
      Yet, just in case you are interested to know more about why I do not favor fixing dogs here’s an interesting video that explains some of the reasons:


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