When Do Boxers Go Into Heat? (Boxer Heat Cycle)

Your female Boxer puppy has been a joy but there’s a nagging question at the back of your mind. When do Boxers go into heat?

Boxer Heat Cycle

And beyond that, if you’re planning to spay your Boxer, when should that be, and if not, what should you expect from your Boxer’s heat cycle

You might also be wondering if the Boxer heat cycle is different from that of other dogs – to which the answer is “Well, maybe!” Confused?

You won’t remain that way for long. This article will work to answer all your questions about heat, spaying, and your role as the proud owner of a beautiful female Boxer. Let’s cut to the chase!

When Do Boxers Go Into Heat?

Your Boxer’s First Heat

Instead of watching the calendar, you’d be well-advised to watch your dog! That’s because heat, especially the first one, differs from Boxer to Boxer.

The usual time for the first heat is sometime in the region of 6 months of age. But it could happen at 4 months. And, since some Boxers are slow to mature, it could be as late as 14 or 15 months. 

Subsequent Heats

After the first heat, your female Boxer experiences ”heat”  around about every 6 months – but don’t expect it to run like clockwork.

Of course, if she got pregnant, her cycle only resumes after her pregnancy ends. That means she’s likely to become fertile in about four months after giving birth. 

How Long Do Boxers Stay in Heat?

The first part of heat is called proestrus. It lasts for about 9 days, and many people think that’s the extent of it. But it’s just the beginning.

During proestrus, the Boxer female is not yet fertile. But her body is preparing itself for fertilization and pregnancy. 

Estrus is the time when your female Boxer can actually get pregnant, and that lasts anything from just 3 days to 11 days. So, the whole process usually lasts between 18 and 21 days, but can go on for up to 27 days. 

If you have a female Boxer in heat, you will need to exercise vigilance to get an idea of where she is in the heat cycle and prevent any unwanted puppies. 

You’ll also want to watch her carefully to ensure that she doesn’t escape. Although she may ordinarily be a devoted companion, she’ll actively look for a mate when she’s in the fertile stage of her heat. 

So, the next thing you need to know is how to recognize when your Boxer is in heat, when she’s fertile, and when it’s over. Let’s look at that next. 

How To Recognize Proestrus

This part of the Boxer heat cycle is almost impossible to miss. You’ll notice changes in your dog’s behavior – she may seem cranky or clingy. 

A look under her tail will tell you that her vulva is swollen, and you may notice a bloody discharge. Don’t count on it though, some Boxer females are very careful to lick themselves clean. 

When Does Boxer Go Into Heat

You might also notice a change in the way male dogs react to your female Boxer. They can sense her approaching fertility and are sure to show an interest.

But, because she’s not fertile yet, she will avoid their advances, sometimes tucking in her tail or sitting down to show that she’s not yet ready to mate.

How To Recognize Estrus

Inexperienced pet owners sometimes think that once the bloody discharge slows down, their female dog is out of heat.

That’s a serious mistake because it’s exactly what happens when your Boxer female enters estrus, the most fertile period of her cycle. 

At this time, she’s just as eager to mate as male dogs are to mate with her. Her pheromones send out signals that they can pick up from far away, and every male dog in the vicinity will respond. 

If she encounters a male, she’ll demonstrate her willingness to mate, sometimes by turning her back and lifting her tail. If there are no male dogs around, she may decide to go looking for one, placing herself in physical danger. 

Diestrus: The End Of Heat

Finally, the heat is coming to an end. You will notice that your female Boxer’s vulva becomes more swollen at first, and then starts to return to normal.

You may see a pinkish discharge. Male dogs won’t seem as interested in her, and she will lose interest in mating because she is no longer fertile. 

To Spay Or Not To Spay Your Boxer – And When To Have It Done

Your female Boxer isn’t going to be sad if she never has puppies, so we can put the argument that it’s kindest to allow a female one litter of pups behind us.

When Do Boxers Go Into Heat

In fact, having puppies makes female Boxers more susceptible to certain types of cancer. 

The real questions here are whether or not you want to breed her and whether you’re ready to undertake the rather intensive business of caring for a female Boxer in heat. Here’s what you need to know in order to make the call.

Never Allow A Pregnancy At First Heat: And When To Spay

With the first heat occurring when your Boxer pup is not yet mature, it’s extremely unwise to allow her to get pregnant on her first heat.

There are greater chances of complications that could have a lifelong impact on health – or even kill her. 

This question affects people who want to spay their Boxers too. It may be better for your dog’s health to spay her before her second heat, allowing her to mature normally before spaying. 

However, if you can’t be sure of preventing that first-heat pregnancy, and don’t have time to guard your dog throughout her heat, it’s better for her health to spay her at about six months of age.

With luck, she won’t have had an early heat. Remember, that can occur as young as four months which is definitely too young to have her spayed. 

Your Boxer’s Heat Cycle And You: If You Plan To Breed Your Boxer

If you plan to breed your Boxer female, that first-heat vigilance (remember, getting pregnant on sexual maturity is bad for her) is only the beginning. You’ll have to be on your toes every six months or so. 

Presumably, you want her to have Boxer pups – and you don’t want masses of male dogs fighting over her in or outside your yard.

You’ll need to keep her safe and comfort her when her hormones are making her moody, and you’ll want to protect your furniture and floors too. 

None of these things are unachievable, but they do require a big commitment from you. Be sure that you’re up to the challenge. As for your Boxer, she’ll just do what comes naturally. 

How To Care For A Female Boxer In Heat

A loving pet parent is likely to feel quite sorry for their Boxer when she is in heat.

It’s as if the poor girl doesn’t know what’s happening to her – especially the first time around. She is going to be super moody – sometimes clingy, sometimes grumpy, and sometimes going off to nest somewhere quiet. 

Some people say that dogs in heat experience pain, but that isn’t proven. However, your female Boxer will need your sympathy and understanding. 

During her heat, and even before she is in the fertile phase, you should supervise your Boxer carefully. She may become reactive toward other dogs, especially males who may try to approach her before she is ready. Keep her indoors.

Once she is fertile and seeking a mate, she may not be as obedient as she normally is. For example, she may not come when called if she thinks there’s a chance of finding a mate.

When she needs to go outdoors, accompany her, and if you still take her for walks, keep her on the leash. 

Make a “nest” for her in a quiet corner of your home. She will have Greta Garbo-like “I want to be alone” moments. 

At times, she may seem almost like her usual self, especially when there are opportunities for play. After all, Boxers love to play, and the Boxer heat cycle probably won’t affect her “fun drive” all that much. 

What To Do About Discharge

You may be wondering what effect that discharge is going to have on carpets and, if you allow your Boxer onto furnishings, your chairs and bed.

Some Boxer bitches are very fastidious, keeping themselves clean through frequent licking. All the same, you might want to be on the safe side. 

Disposable dog diapers might be just what you need. And some people even use adapted “human” underwear to prevent mess.

Alternatively, you can cover your furniture or carpets instead of covering your dog. There isn’t really all that much blood, and that’s the approach I take. 

Boxer Heat Cycle: When To See A Veterinarian

A little bit of blood, occasional appetite loss, cranky or clingy behaviour, frequent drinking and peeing – these are all normal for a Boxer in heat. But things can go wrong.

Boxer And Heat Cycle

If the bleeding is heavy, it may be a good idea to have it checked out. And there’s an infection of the womb that can occur following estrus. 

It’s called pyometra and it needs treating. You might notice pus around the vulva, and your dog will definitely not seem well.

She may go off her food, appear bloated, seem constantly thirsty, and even vomit. These symptoms usually occur anywhere between two and eight weeks following estrus. 

That’s because the hormonal effects of estrus make the womb susceptible to bacterial infection, so even if you think your Boxer is pregnant and it’s just morning sickness (dogs can experience that), let your veterinarian check it out. 

Having said this, Boxers in heat don’t usually need veterinary attention, but if you’re worried, get a professional opinion. 

You might also be worried if your Boxer doesn’t go into heat at the expected time. It doesn’t hurt to get her checked out, and you might have spotted a symptom of something more serious than an irregular heat cycle.

It’s better being safe than being sorry!

Can My Boxer Get Pregnant Outside Of Heat?

Your dog cannot get pregnant when she is not in heat. As she prepares for fertility, she will actively prevent males from approaching her from behind.

At other times, dogs often engage in dominance displays in which they mount each other and “hump.” 

Even females sometimes do this to males. I once had quite a spectacle in my garden when my male Doberman mounted my friend’s male Staffie, and my female Boxer acted as the “caboose” at the back of a doggie train that humped its way around my garden.

I guess you had to be there to see how funny it was, but it was truly hilarious! Even the Staffie in front seemed to be taking it in good spirit. 

At all events, your female Boxer won’t get pregnant if she submits to this form of one-upmanship – even if she isn’t the “caboose!” Thank heavens humans don’t do this. A day at the office could turn out pretty strange. 

Boxer Heat Cycle: The Most Important Things To Remember

As pet owners, it’s our role to be attentive towards our dogs. You can get a fair estimate of when Boxers go into heat, but each dog is different and your girl’s cycle might not match the calendar. 

Even if you’re planning to spay at six months, your puppy can go into heat sooner than expected, and although heat is supposed to happen every six months, it doesn’t always. 

The best way to know when your Boxer is in heat is to keep an eye out for the symptoms. With Boxers having larger-than-life personalities, you’re sure to spot that things aren’t entirely normal.

It’s not rude to take a peep under her tail. That swollen vulva is a giveaway symptom of heat. 

Be empathetic towards your Boxer in heat. Give her extra love when she wants it, and peace and quiet when that’s what she prefers.

Guard her against any unwanted advances from male dogs. You can’t blame them, your girl is giving off signals they can’t resist. 

Do consider spaying your female Boxer, either at six months, or after her first heat. Don’t do it sooner than six months – that is very likely to cause health issues. 

There are so many rescues and unwanted dogs out there, and breeding dogs as a sideline isn’t really profitable.

Despite the high prices that Boxer pups can command, you’ll find yourself with a lot of vet bills to pay, and plenty of your time being taken up. 

If you do decide to breed your Boxer, don’t expect to get a “clone” of the mother, and do be willing to invest a lot of time, energy, and money into taking care of your dog and her puppies.

Don’t allow her to have more than four to six litters. It will exhaust her body and shorten her lifespan. 

Now you know everything about the Boxer heat cycle. We hope you found this information useful!


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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