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.

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sonja odell
7 years ago

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

7 years ago

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.

6 years ago

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

Romano pesce
6 years ago

My staffie is now bleeding and she seems to be abnormally swollen

6 years ago

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

Christopher Pellicano
6 years ago

I have a pure bred bull terrier. AKC regiestered pet. She is 8 months old. She is exhibiting some very unusual behavior. She is highly intelligent. The vet told me that her purebred DNA could be of concern. He said she could flip out on me and get very dangerous. Watching her grow up stong and beautiful has been a real joy. He has green eyes and snow white color. Any fact behind this vets opinion that her DNA will kick in and she becomes dangerous?

Reply to  Dorothea Cornelius
3 years ago

Definitely not a purebred English bull terrier if Eyes are green, actually a purebred English bull terriers eyes are black. My girl had her first heat at 7 months, now she’s approaching 17 months and still no signs of a second heat. Is this normal?

6 years ago

Hi, I am wondering after a female heat cycle, to know when the next cycle should begin, should I count from the beginning off her last cycle, or the end? Thanks

5 years ago

Hi, I would like to ask if a dog will get pregnant in her late estrous cycle? I brought her to the vet last time and did a smear test, that’s when I learned that she was on her late estrous stage already. I wasn’t able to track the start of her cycle since I was waiting for a bloody discharge, but I wasn’t able to track a bloody discharge. Same goes on her 2nd heat cycle the difference was on the 2nd heat i bred her on her late pre-estrus and at the beginning of estrus. I was only able to know that she was on heat because of my male dog licking her private parts and trying to mount her. She is a 24mos old siberian husky.

China James
5 years ago

My Staffy ended her heat about 60 days ago but she started to present to the male dogs she is around. The dog we live with continually tries to mount her and wait s for her outside the door and she has no problem with him mounting her and she runs up to him and let’s him do it. I am concerned she could go back on heat with no visible signs because she is around an intact male. Is this true? I am wondering your opinion on what to do as he has inseminated her yesterday and it’s not a pregnancy we want. I will take her and get a prog test. I am not sure what else to do.

4 years ago

Hi there
My staffy girl is 17months and has had 2 heat cycles so far (4months apart) i have spoken to a vet and she doesnt seem to concerned as long as the blood is normal in colour which it is. As shes quiet young our vet and breeder have both said she may regulate to every 6 months as she gets older.
But can they go every 4months?

4 years ago

My girl, is 10 months old 39 days since possible breeding. Her teats and vulva are still swollen. Teats glands seem to be going down. Do you think this is possibly a false pregnancy or real?

4 years ago

My female has been in heat four weeks and a one day. Visually there are no signs that she even should be, but my female is still VERY MUCH trying to breed her. Can anyone help us? Should be bathe her to remove any residual smells? What’s the longest anyone knows of a cycle?

Nicole W
4 years ago

Hi was wondering if you could help me my girl just turned a year on the 18th of March she started her season on the 10th of March she was really swollen then she started bleeding a few days after now that’s 4 weeks up and she’s still really swollen , really red and bleeding again , she won’t stop licking herself constantly she can’t sit still without licking am worried about her could you help ?

3 years ago

Hello my girl is a pitbull 10 months and haven’t got her first heat cycle as yet. Should I be concerned?

2 years ago

My bitch has been out of season for about a week but I also have a male this was her first season since she’s come out it her nipples have gone big and teets swelled abit should I be worried she’s 8months old xl bully

2 years ago

I have a female bull terrier that turned 8 months on Christmas Eve. Her vulva is swollen and has been spotting since Wednesday. Everything else about her is normal. Could this be her first period?

1 year ago

Hi all,
I have a 20 month old beautiful EBT. She had her first (short) heat at 7 months.. She had her full heat in August this year 2022..
Its only October now and this last week she has displayed behaviour like nesting, crying nearly constantly and extremely boisterous stuff when out walking… Im wondering if she may be approaching another heat? Her vulva isn’t swollen (yet?) and shes gone of certain foods aswell..Ive read different things but was hoping someone may be able to shed a bit of light through experience…
Thank you for reading
Jennifer 🐾ebt🐾

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