When Do American Bullies Go Into Heat Cycle?

Your female American Bully is your pride and joy, and you’d love her to have at least one litter of pups to make you a proper pet grandparent.

But when do American Bullies go into heat? You’ll also need a full understanding of the American Bully heat cycle so that you know the best time to breed her.

When Do American Bullies Go Into Heat Cycle

Relax! You’ll get all the answers you need right here, and with American bullies generally experiencing uncomplicated pregnancies and natural birth, your hopes for a litter of puppies are on the way to being realized.

But first, it’s time to understand the various stages of American Bully heat and get answers to questions like how best to care for your Bully during her heat, and even whether you can still hope to spay her if you missed the ideal date and would prefer her not to breed at all. Let’s get down to business!

When Do American Bullies Go Into Their First Heat?

It’s your first question: “When do American Bullies go into heat?” And it’s a good place to start your fact-finding mission.

Like all dogs, most female American Bullies reach puberty shortly after they are six months old and your Bully will go into heat soon after puberty.

However, at six months, she is not yet fully grown, and having pups so early in her life can cause various health problems.

The general recommendation is to only consider breeding your dog during her third heat cycle, which occurs at about one-and-a-half years of age. However, you do need to be aware of her heat cycle.

Male dogs will try anything to get at her during heat, and they’ll fight among themselves to be the first to reach her.

So, during her first two heat cycles, your main aims will be to prevent a pregnancy and limit the chances of unpleasant confrontations between neighborhood dogs.

How Can You Tell If Your American Bully Is In Heat?

There are two types of symptoms to look out for: behavioral symptoms of heat and physical ones. Most pet owners notice the behavioral symptoms first, but the physical ones are the real confirmation of heat.

American Bully Heat Cycle

Behavioral Signs Of Heat In American Bullies

Your American bully may become fussier about her food or develop a raging appetite. She may seem edgy, pacing around and possibly panting more than you’d expect her to.

Some dogs starting in heat, on the other hand, get lazier, preferring not to play and sleeping more than they ordinarily would.

During the early part of her heat cycle, your American Bully won’t be ready to mate, and she will tend to get irritable with other dogs, including female dogs, in your family if they try to approach her.

She may even get irritable with human family members, so give her space if she isn’t in the mood for interaction.

As she gets nearer to readiness, she’ll switch to being “flirtatious” with male dogs, presenting her rear as an invitation to mate.

Very often, female Bullies will start mounting and humping everything from other dogs to inanimate objects: a very clear sign that she’s in heat!

She may also start to invite males by leaving scent markers. Frequent, small urinations could be a sign of this.

And, since there will be discharge from the vulva, she will tend to clean her genital area by licking it frequently.

Attempts to escape and go out in search of a mate could have serious implications for your dog’s safety, so be alert for this behavioral sign of heat too!

Next let’s look at the four physical stages of the heat cycle. Understanding them will help you to understand your dog better, and when it’s time to breed your American Bully, you’ll be able to spot the best time to have her serviced.


Proestrus is the first stage of the heat cycle and it lasts from 3 to 17 days. The most notable sign of this is a swollen vulva and you may notice that she’s grumpier or more affectionate than usual. If you notice light bleeding, this is perfectly normal.

Halfway through the first week, it will usually increase somewhat, but your dog is not yet fertile. Since she isn’t ready to mate just yet, she’ll tuck her tail over her vulva or sit down whenever she sees another dog.


Estrus can last anything from three to 21 days, but the average for American Bullies is 9 days. Your dog is now fertile and her breeding instincts take over.

You’ll notice that discharge from the vulva lightens to a pinkish shade and that its initial swelling has subsided somewhat.

Because she is ready to mate, she will start “flirting” with male dogs, presenting her rear as previously described.

During this time, she may actively seek a mate, even if that means escaping from your yard. Monitor her closely.


During Diestrus, your dog is no longer fertile and begins to behave normally. Pregnant or not, this stage will last around 60 days.

Diestrus ends when the puppies are born, or if your dog isn’t pregnant, can last up to 90 days. The vulva’s swelling subsides, and since she is no longer interested in mating, she stops flirting.


Also known as the “resting stage,” Anestrus lasts from 100 to 150 days. After this time, your dog begins the heat cycle again beginning with proestrus.

On average, your dog will complete the full four-step cycle in about six months, achieving fertility twice a year.

How Often Do American Bullies Go Into Heat?

When talking about “heat” most pet owners are referring to the proestrus and estrus stages of the heat cycle.

Although the general rule of thumb says that female American Bullies will go on heat every six months, your dog’s body may have other ideas!

There can be variations of four to six months in the heat cycle. The length of time she spends in each stage of the heat cycle will be responsible for the variation, and this not only varies between different dogs, but also in individual instances.

So although your dog’s heat cycle was a certain length of time last time around, it may be different this time.

American Bullies Heat Cycle

Adding an element of unpredictability, there’s also the matter of “split heat” or “silent heat.”

When this occurs, your female Bully goes through proestrus but fails to ovulate. Her body tries again a few weeks later, and all of a sudden, you find that she’s in full, fertile heat.

How often do American Bullies go into heat? The usual answer is “Every six months,” but as we have seen, that’s just a rule of thumb and the real space between heats could be shorter or longer.

The bottom line? Nothing beats keeping a close eye on your American Bully’s female cycle.

When Is A Female American Bully Most Fertile?

There are some very scientific ways of determining the most fertile time, but you can do it the old-fashioned way by observing the color and texture of the discharge from her vulva.

Before she becomes fertile, it will be red. When it becomes clearer and more watery, she is in her most fertile stage, and her behavior will reflect that.

Remember, she may not become pregnant immediately after being covered. Actual fertilization could happen up to a week after the event.

So, if you’re trying to calculate the puppies’ arrival time, you’ll have to take this into account.

How Do Male Dogs React To A Female’s Heat?

When she enters estrus, your female American Bully will secrete pheromones. They’re meant to attract male dogs, and they can be smelled for up to three miles away.

As soon as they get this scent, intact male dogs will have a strong urge to find its source and their behavior is triggered by hormonal changes they undergo after being triggered by pheromones.

Male Dogs React To A Female's Heat

At this point, they will do anything possible to reach your dog, even if they hurt themselves in the process. And if they encounter competition from other males, they will fight.

The female is safe enough. After all, she is the “lady-love” who is the target of their wooing.

How Long Does An American Bully Stay In Heat?

If we define “heat” as the fertile stage of the heat cycle, as most people do, then you should be ready for considerable variations.

In some instances, the fertile estrus stage of heat can last as little as four days, but in others, it can continue for up to three weeks.

However, most female American Bullies won’t go to either extreme, generally sticking to the average time of nine to eleven days of fertility.

You’ll know that her fertile stage has ended by keeping an eye on her condition.

The vulva, which becomes somewhat less swollen than it was during the first, infertile stage of the heat cycle, begins to subside during fertility.

When it has returned to its normal size and there is no more discharge from the vulva, her heat is over. You should also notice that her behavior becomes more “normal.”

Scent marking, the desire to wander, and her flirtatious behavior around male dogs will come to an end.

Can You Spay An American Bully While In Heat?

In theory, the answer is “yes.” In practice, you would be best advised to wait for her heat to pass.

If you’re having problems with neighborhood dogs or can’t spend time keeping a close eye on your female American Bully, it may be advisable to place her in kennels until she’s out of heat.

Many veterinarians are reluctant to spay dogs in heat since serious complications can occur, especially in heavy, deep-chested dogs like the American Bully.

Simply put, there’s a higher chance of internal bleeding or a botched op, so if you were planning to spay but missed the often short time between puberty and heat, waiting it out will be best.

How To Take Care Of A Female Bully In Heat

Striking a balance between being overly protective and just treating her as normal can be difficult to do.

Neither of these will be good for your dog. While you shouldn’t wrap her in cotton wool, she definitely needs some extra care.

Begin by being sensitive to your American Bully’s needs. If she’s feeling lazy, don’t try to force her to exercise. If she looks like needing to let off some steam, give her the exercise she craves.

However, if this takes the form of walks, avoid places where you might meet up with off-leash males, and never let her off leash even if she’s ordinarily very obedient.

Care Of A Female Bully In Heat

Supervise your dog carefully. Your home-loving American Bully may transform into an escape artist in her natural quest for a partner, and leaving her unsupervised in the yard could be her cue to make a run for it.

You also need to consider male dogs who will dig under, climb up, or jump over even the most formidable fences in their attempts to reach a receptive mate.

Since “close supervision” means a lot of time indoors, you may be worried about that discharge wrecking carpets and furniture.

It may be time to invest in some dog diapers! Yes, this product does exist!

Try to be sensitive to your American Bully’s heat-induced moodiness. If she’s grumpy, try soothing her, but back off if it seems unwelcome. If she’s clingy, give her the extra love and attention she craves.

It’s quite common for an American Bully in heat to whine and pace, seeming to be uncomfortable. Try distracting her.

If her behavior continues for a long time or you think she’s in pain, then her heat may not be to blame. Call your veterinarian.

Appetite changes also need to be dealt with. Normally, this manifests as her being less interested in food and less willing to eat.

You may have to tempt her with doggie treats. Just be sure that whatever you offer is right for dogs. Human food can be dangerous to canines. Regardless of her appetite, ensure that what she eats is nutrient-rich.

Finally, although there’s only anecdotal evidence to prove it, consuming chlorophyll may help to mask her pheromones so that she attracts less romantic overtures from the neighborhood males. Feel free to try this as it certainly can’t hurt, but don’t bank on it.

Final Words

Don’t expect American Bully heat to be an easy ride for either you or your dog.

If you really want her to have puppies, you’ll have to go through the process at least twice before you should allow her to breed, with a final heat before she becomes pregnant.

Remember, dog breeding is not as profitable as many people think it may be, and it’s been proven that spayed bitches who never had pups have fewer health-risks and may live longer on average.


Hi there, my name is Blake and I have an American Bully named Rocky. I fell in love with the breed around ten years ago after seeing some of my friends adopt a Bully. I love the combination of the muscular physique and calm, loyal companionship that the American Bully breed has to offer. My enthusiasm for the breed has led me to train as a dog behavioralist and trainer. Over the last ten years, I have supported many households in raising their American Bully and maximizing the potential of the breed. I’m delighted to share my knowledge and expertise on this site.

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