When Do Great Danes Go Into Heat? (Heat Cycle)

Is the Great Dane heat cycle different to that of other dogs? It certainly can be, and that’s just why we’ve written this article.

When Do Great Danes Go Into Heat

You may have a lot of other questions about Great Danes in heat, when to spay, and so on – so we’ll go into that in greater detail too. 

Let’s begin with the short answer before getting into deeper detail. Great Danes experience their first heat somewhere between 10 and 24 months of age.

However, some have been reported to begin heat as young as 8 months old. The average age for Great Danes to begin heat is said to be in the region of 12 – 18 months . 

WhyIs Great Dane Heat Often Later And Less Frequent Than Other Dogs?

Giant dog breeds, and Great Danes are very definitely among these, often reaching maturity more slowly than smaller ones.

They keep growing for longer, and they often reach sexual maturity later too. It’s not just maturity that happens more slowly either. 

While the average dog has heats spaced at six-monthly intervals, Great Danes usually only go on heat once a year.

Once again, this is related to their size. Some small breeds of dogs can have 3 heat cycles a year. 

Can A Great Dane Get Pregnant During Her First Heat?

The heat cycle shows sexual maturity and means that your Great Dane is fertile and can become pregnant.

But physical maturity is still a long way off when a dog has her first heat and so is mental maturity. 

That means that a young Great Dane that falls pregnant on her first heat may not have the physical or mental capacity to be a mother yet.

On the physical side, there are greater chances of complications that could prove fatal to her and her puppies. On the mental side, she might be a poor mother who has no idea of how to cope with her litter.

There are longer-term impacts too. With both her still-developing body and her puppies craving nutrients, a young female Great Dane can deplete her reserves quickly.

And this will occur at a time when it’s vitally important for her to develop healthy bones and a healthy heart. The result could be a shorter life.

Just as you wouldn’t want to see a young pubescent girl getting pregnant and having a baby, you shouldn’t want the equivalent for your Great Dane.

That’s just as true if you are looking forward to her having a litter of happy, healthy puppies. Give her a chance to grow up first! 

However, one thing will be against you. Your Great Dane herself. Although she doesn’t have any way of knowing what is happening to her body and hormones, she’ll be hell-bent on getting pregnant.

It will be your task to make sure that she doesn’t.  We’ll discuss how to cope with a Great Dane in heat shortly.

First, let’s suppose that you’re hoping to breed your Great Dane. How long will you have to wait?

When To Breed A Great Dane

Wait until your Great Dane is at least two years old before allowing her to get pregnant. Some breeders prefer to play it safe and wait for their female Great Dane to be at least three years old. 

That means that you will be working to prevent your Great Dane from becoming pregnant for one to two heat cycles before allowing her to be covered.

Great Dane And Heat Cycle

Even then, you will doubtless want to have some control over who fathers the puppies. This is far more easily said than done, so consider spaying as an alternative. 

If you’re still keen to go ahead with breeding, be sure to have your Great Dane checked out by a veterinarian and ask for genetic screening.

You have two concerns here: her health, and the health of any puppies she might have. 

When To Spay A Great Dane

If you don’t want your Great Dane to have puppies or might like it but don’t have time to care for a Great Dane in heat, it is wisest to have your dog spayed before sexual maturity.

This may also reduce her chances of mammary cancer, but could increase the chance of certain other cancers. 

Research is ongoing and your veterinarian is sure to have an informed opinion. In general, spaying at, or slightly before, 12 months is generally thought to be right for Great Danes.

Discuss the pros and cons  of earlier spaying vs later spaying and consider your own limitations too.

Although you might want to see your Great Dane through her first heat before spaying, you might not have the time or patience for what is a pretty tough time for both you and your dog. 

Although there are some myths about spaying – for example that getting it done before your dog is fully-grown will affect her growth, there are some truths to take on board. 

For example, spaying a Great Dane, or any other dog, while they are in heat is more risky – so much so that some veterinarians won’t do it.

Others will be willing to – after warning you of the dangers – and at a higher cost in the event of any complications. It’s not an ideal situation whichever way you look at it. 

If your Great Dane’s first heat has taken you by surprise, consider whether you can supervise her during a heat.

If not, can you place her in boarding kennels? The only other alternative is a spay that’s riskier than it ought to be. 

How To Know When A Female Great Dane Is In Heat

It’s impossible to know when the first heat will occur. After that, it’s almost as difficult to know when your Great Dane will experience her next heat.

The only way to know when your Great Dane is in heat is to observe her body and her behavior. 

Great Dane Heat Cycle

Physical Changes

  • The vulva becomes swollen and looks redder: This is the outer part of your dog’s vagina. 
  • There is blood or discharge from the vulva: you may or may not see this because some females don’t bleed much and clean themselves often.
  • Frequent licking of the area under the tail: this might show that she is clearing away blood or discharge.
  • Needing to potty more frequently: you’ll easily pick up this cue if your Great Dane spends a great deal of time indoors with you. What she is doing is scent marking to tell other dogs that she is about to become fertile. 

Behavioral Changes

  • Anxiety or nesting behavior: Your Great Dane is experiencing hormonal changes and she may seem clingy, bewildered, or eager to seek comfort on her own. 
  • Mounting and humping behaviour: this is really hard to miss on a Great Dane – but not all dogs on heat do it. 
  • Very hungry or off her food: appetite changes always mean something. Could your Great Dane be in heat?
  • Cranky with other dogs: During the early part of heat, before she’s ready to mate, your dog might get irritable with other dogs around the house – especially males.
  • Sitting down when she is approached by males: In early heat, your Great Dane is giving off pheromones but she isn’t ready to mate. She may “defend” her rear end by sitting down if they approach or by covering it tightly with her tail.
  • Getting flirty with males: As she enters fertility, your Great Dane will be looking for a mate. She’ll also signal that she’s ready by keeping her tail away from the genital area. 

Stages Of Heat And What They Mean

Your Great Dane won’t be fertile throughout her heat cycle, but it will be hard for you to know exactly where she is with it.

All the same, the time when you think heat is coming to an end could be the time when she’s most fertile, so let’s look at the stages of heat next. 

Great Dane Female Heat Cycle

Proestrus: Usually about 10 days

Your Great Dane is not yet fertile, but her body is preparing itself for pregnancy. This is the time when dogs bleed from a swollen-looking vulva. 

You will notice behavioral changes during this phase if you are observant, and that gives you a good chance of preventing an unwanted pregnancy. 

Estrus: Usually 5 to 9 days

Estrus often catches dog owners unawares. As they see the discharge from the vulva lessening and changing to a lighter pink color, they think that heat is coming to an end.

But this is the time when your Great Dane is fertile, and it’s the time you should guard her against pregnancy or a random match with a passing male. 

Supervise your Great Dane carefully. Beware! No matter how obedient and home-loving she usually is, she might turn into an escape-artiste and go in search of a mate.

Diestrus: 6 to 10 weeks

Your Great Dane is no longer interested in “the boys” because she is no longer fertile. The vulva is still swollen, so it can be hard to be sure whether she’s still fertile.

She  may still be attracting males even though she no longer wants to be covered – those pheromones linger for a while.

You might notice that she stops “flirting,” however, and that’s a good sign that she can no longer fall pregnant. Even if she didn’t get pregnant, you will see some enlargement of her mammary glands during this phase. 


If your dog didn’t get pregnant, her reproductive system takes a break now. All symptoms of heat are gone, and your dog is back to her old self until it’s time for the next heat. 

Note: Your Dog Doesn’t Go By the Calendar

Managing a Great Dane in heat is tricky, and knowing when it’s safe to leave her to own devices can be even trickier.

Remember that we said estrus usually goes on for about 5 to 9 days? Well, it can go on  for as many as 20 days!

Whether or not you are allowing her to breed, your Great Dane will continue to attract males after she is no longer fertile (during diestrus) and it can be a dangerous time.

At this point, she is willing to mate. Fights can ensue. You will have to guard her until at least day 21 and possibly longer. 

Tips For Caring For A Great Dane In Heat

Once you realize that your Great Dane is going into heat, you must begin supervising her closely. Keep her indoors with you, and when she has to go outside, stay with her.

Consider using a leash since she may find her drives so strong during estrus that she disobeys you or tries to escape from you. 

Cut out the doggie walks. Your Great Dane in heat will attract plenty of male dogs and things can get quite stressful for you, them, and your Great Dane. Who wants to be the center of a dog fight? 

Some females bleed more than others during heat – you might hardly notice it, or there could be a steady flow of blood. If you’re worried about your furniture, consider using special doggie diapers.

Be patient with your Great Dane’s moodiness. Comfort her when she wants to be comforted, and leave her alone when she wants to be left alone.

During a first heat, the anxiety is often quite pathetic. Do what you can to soothe your dog. 

While you are sure to find any suitors your Great Dane attracts annoying, keep your cool. They’re just following their instincts and she’s pretty irresistible right now.

Your job is to keep her away from them. If they have strayed from their homes and are getting annoyingly invasive, call animal protection services. 

Should You Breed Your Great Dane?

The answer to this question lies with you. Your Great Dane won’t miss having puppies if she’s spayed before her first litter.

So, think about the reasons why you want to breed her, because your decision will affect you as much or even more than it affects your dog. 

If it’s because you’re hoping to get a carbon-copy of your dog, that isn’t going to happen. As for the income from breeding a Great Dane, it isn’t as high as it may look.

There’s your investment of time and stress to consider as well as veterinary costs – these can be high. 

However, if you’re passionate about the breed and are willing to take the many downsides of dog-breeding along with the pleasure of seeing those cute puppies, breeding your Great Dane might be personally rewarding for you. 

At the same time, do consider that these rewards may have hidden costs too. Research shows that “sterilization was strongly associated with an increase in lifespan.” Food for thought!


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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