How Long Do American Bully Females Stay in Heat?

female american bully in heat

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If you’re asking this question, one of two things has probably occurred. You want to fix your dog, and they’re in heat, so you’re waiting until it’s over, or you’re interested in breeding your American Bully and want to know as much as possible to maximize your chances of a successful litter.

American Bullies will stay in heat for anywhere from two to four weeks. They will go into heat approximately every six months. This starts at around six months of age and continues for the rest of the dog’s life, although the time between heats will get longer.

In the rest of this article, I will go over how the heat cycle works, how long it lasts, and the optimal time to breed your dog.

How Long Does Heat Last?

Your American Bully’s heat cycle will last anywhere from two to four weeks, during which she’ll only be highly fertile for around five days. This is typically estimated to be anywhere from 10-14 days after their first day of heat, but progesterone testing is the only reliable way to measure this. 

You’ll notice that your female is going into heat because her vulva will become swollen, and you will start to notice bloody discharge. She may also begin to act more anxious and seek out and present herself to a male dog.

The first day that you notice blood is the day that counts as “day one” of your dog’s heat. After that, your dog will continue bleeding for anywhere from two to four weeks.

On average, your dog will ovulate a little over a week into her heat and be the most fertile from days 10-14. Most females become fertile and receptive right around day 11, although this can vary greatly. Some dogs have short cycles, while others won’t ovulate for a few weeks.

After your dog has ovulated, the eggs will mature for a few days before they become fertile. This is different from humans because we are fertile as soon as we ovulate. No maturation time is needed. After your dog has ovulated, she will be fertile for a little less than a week. Then, if she hasn’t been successfully bred, she will slowly come out of heat and go back to normal.

When Do Dogs Start Going Into Heat?

The average dog will start going into heat at around six months of age, although that will vary based on the size and breed of the dog. It is not recommended that you breed them for their first two cycles as they are still maturing physically during that time.

Typically, dogs will go into their first heat at around six months of age. However, this greatly varies depending on the size, breed, and condition of the dog. 

A dog that has been malnourished will go into heat at a later age, similar to how malnourished children will delay their puberty. That is why, for a breeding dog, it is vital to ensure that they are receiving adequate nutrition from a young age. 

The size of your dog is also an indicating factor of when they will go into heat. Smaller dogs will often go into heat at a younger age, sometimes as young as four months old, whereas larger dogs will take longer to mature and therefore longer to have their first heat. They will also tend to cycle more rapidly as adults having three to four heats per year, while larger dogs may have only one per year. 

American Bullies are medium-sized dogs, so they tend to go into heat right around six months of age and should continue to cycle around twice per year for the peak years of their life, only slowing down once they reach old age.

What’s the Best Way To Determine When Your Bully Is Ovulating?

While it is commonly recommended to breed your dog between days 10 and 14 of their cycle, this is not a reliable way to successfully breed your dog. Every dog is different and will be fertile at a different time during their cycle. 

The only reliable way to determine when your dog is ovulating is by having a vet perform vaginal smears or a serum progesterone test. The smear will track changes in the cells around and in the vagina while the serum test monitors the rise and fall of progesterone.

Your vet should be able to perform both of these tests in the office, although sending them to a lab can sometimes lend more accurate results. The smear test is typically done every day for several days to monitor changes in the cells of the vagina. It is minimally invasive and has virtually low risks.

However, it is not as accurate as a serum progesterone test.

A serum progesterone test is performed via a blood test and is considered highly accurate. Typically, a few of these tests are done over several days to monitor hormones’ rise and fall, allowing us to predict the day of ovulation accurately.

It is more expensive and more invasive than the other tests, which is something to consider.

If your female doesn’t have a history of unsuccessful breedings and you’re not transporting her large distances, then vaginal smears could be an excellent option for you. They’re less expensive and less invasive, meaning that you’re putting your female through less stress. 

If your female has a history of unsuccessful breedings or you’re paying for semen to be shipped or transporting her great distances, then you may want to pay for the more accurate serum progesterone test.

Which Breeding Style Has the Highest Rate of Success?

newborn american bully puppy

Despite the recent rise in the popularity of artificial insemination, natural breeding remains the most effective way to breed your dogs. This is because putting the dogs together allows for several breedings over a few days, maximizing the female’s fertile period.

Artificial insemination has recently become the breeding option of choice, especially in the bully world. Before artificial insemination became more widely accessible, your stud options were limited due to distance. Yes, you could choose to ship your female, but that comes with many risks and, due to the stress of transport, could stop or delay your female’s cycle, making it harder to achieve successful breeding.

With artificial insemination, you no longer need to worry about the risks that come along with shipping your female. You can ship semen from wherever you want in the world, thereby giving you more opportunities to diversify your bloodline. The actual breeding process is safer because you do not risk a fight breaking out between the two dogs.

The downsides to artificial insemination are that it can be costly depending on where you’re shipping from and has led to a less diversified worldwide population. While artificial insemination may allow you to diversify your line more, it has actually lowered the breed’s integrity overall. Now that everyone has access to the five best studs in the world, that’s all anyone is using, which makes the population less hardy. 


On average, American Bully dogs will stay in heat from two to four weeks, although they will only be highly fertile for around five days.

They start going into heat at approximately six months of age, although it is not recommended to breed them until they are at least a year old or have gone through one to two heat cycles.

If you choose to breed your dog, make sure you are doing so responsibly. You should be able to afford any emergency medical expenses and perform all needed health screenings and checks on both the mother and the puppies. 

3 thoughts on “How Long Do American Bully Females Stay in Heat?”

  1. Charles jay Rosales

    Good day, we have two bullies lico and lyca and also we have 5 ordinary dogs 2 female and 3 males in our house nico our male bully is 12 months old. One evening one of our closest friend brought their female bully because they asked us stud their female bully name chicka so they brought their personal shooter to perform insemination to chicka we successfully stud 3 days once a day, 3 times to chicka sadly and accidentally our ordinary dog stud chika after the third insemination my question is that what will happen to the breed if ever Chica got pregnant,what will happen to the puppies of chicka?

  2. Why do Bullies stay in heat longer than the average dog and bleed for a longer period of time? My girl is in her first heat cycle and this is Day 17. She is still bleeding. She hates her heat diapers with a passion and will bite it off her body and then proceed to chew it up into hundreds of little pieces unless I take it from her immediately. She will sometimes sneak into her crate like she is being SO good, but then I will catch her in there chewing up her diaper. She is also still showing signs of anxiousness that started on Day 1 of her heat. She never barked very much until her heat cycle and now she barks and barks at the least little sound outside. Oh God! She has also started chewing more aggressively during her heat. So far she has only chewed her toys, but she has chewed up some strong and sturdy toys. Will the barking excessively and the chewing aggressively go away after her heat is over? Please say they will. I’m dying over here! Lol! I will be so glad when this first heat cycle is over!!

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