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When Does a Great Dane Go Into Heat? Vet-Reviewed Facts & FAQs

Written by: Nicole Cosgrove

Last Updated on April 17, 2024 by Dogster Team

a great dane dog lying outdoor

When Does a Great Dane Go Into Heat? Vet-Reviewed Facts & FAQs


Dr. Paola Cuevas Photo


Dr. Paola Cuevas

Veterinarian, MVZ

The information is current and up-to-date in accordance with the latest veterinarian research.

Learn more »

Whether you own a female Great Dane or are planning on getting one in the near future, you might be wondering about when they’ll have their first heat. Don’t worry because we are here to answer any questions you may have! From understanding the physical and behavioral changes your furry friend will go through to knowing how to properly care for them during this time, we’ve got you covered. You’re about to learn everything you need to know about it, so keep reading!

First things first, it’s important to know that every Great Dane is different, so their heat cycle timing will vary. Most dogs usually have their first heat around the age of 6–10 months, but large breeds tend to be much later. Great Danes are no exception and usually have their first heat between 10–24 months old. Although some individual Great Danes may reach sexual maturity earlier than smaller dogs, overall, they tend to mature less rapidly—like other large breed dogs.

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The Heat Cycle

To get a better understanding of your Great Dane’s heat cycle, you’ll need to learn about the heat phases. A female’s cycle is separated into four stages, which all have a specific purpose in reproduction.

a mantle great dane at a garden
Image Credit: mkzdillon, Shutterstock

1. Proestrus – Infertile

Proestrus often lasts 9–10 days and during this stage, your female dog will not yet be interested in mating. During this stage, you will probably see some signs that your dog is in heat. The vulva will begin swelling and there will be blood-tinged discharge. Male dogs may try to pursue her during this time, even though she is not ready to reciprocate.

2. Estrus – Fertile

Female dogs are most fertile during the estrus stage, which also normally lasts 9–10 days. The dog’s discharge will begin to lessen, often leading owners to think that their dog’s heat is over. Nothing could be further from the truth. This is the period when your female Great Dane will be receptive to males and will become pregnant if successful copulation is allowed.

3. Diestrus – Return to Resting

If your female didn’t mate during the estrous cycle, and therefore is not pregnant; it will enter the next phase called diestrous.

Diestrus may last for about 2 months and is the stage where hormonal changes will slow down a lot. This means the female will no longer be interested in mating.

4. Anestrus – Resting

Anestrus usually lasts for 4–5 months, during which the female dog does not show any physical signs and shows no interest in mating. During this stage, the body is preparing for the next cycle.

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Signs Your Great Dane is Going into Heat

As the first time a Great Dane may go into heat varies, you will have to keep an eye out for signs that your dog is entering the proestrus stage. Fortunately, the signs for all dogs are usually the same and include the following:

  • Mood changes
  • Tail held differently
  • Swollen vulva
  • Licking their vulva
  • Bloody or brown discharge
  • More frequent urination
  • Interest in male dogs

Do Great Danes Experience Menopause?

Unlike humans, dogs do not go through menopause as they age, and their heat cycles will continue into old age. This means that female Great Danes that are not spayed will experience estrus cycles for their entire lives. When they are young, they will usually have about two heat cycles a year, becoming less frequent as they age. By the time they are in the latter years of their life, it will be about once a year.

Great Dane on a stone path
Image Credit: axi-schnaxi, Pixabay

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How to Care for a Great Dane in Heat

You’ll want to make this time as comfortable as possible for your best pal. Here are a few essential tips for caring for your Great Dane when she goes into heat.

Be Prepared for Mood Changes

There will be some personality changes in the first three stages of the heat cycle. You should inform your family that for a short while, your Great Dane may not be her usual self. This can be quite troubling for owners, but rest-assured that mood changes are to be expected and are perfectly normal. Your role is to support her with whatever she needs, whether it is privacy and space or comfort and attention.

Don’t Leave Her Alone Outside

Whenever your Great Dane is outside, she should always be supervised. During the first stage, she may not be interested in male dogs, but they will be interested in her! If your yard or garden is not secure, then you will need to supervise her whenever you let her out to make sure no male dogs get to her.

Once the second stage, the estrus stage, starts, she will be the one trying to get to the male dogs. She will try very hard to get out to find a partner, and obstacles and fences that you previously thought to be impassable will be no match for her.

man with his great dane dog by the pond
Image Credit: Dmussman, Shutterstock

Keep Her Area Clean

During the first two stages of the estrus cycle, your dog may discharge blood which can be a little messy. You want to keep her area as clean at all times to reduce the build-up of bacteria to prevent bacterial infection. You can keep her cordoned off in a part of the house and change her bedding every few days. People often use their old bath towels for their dogs to sleep on.

Watch Her Appetite

When in heat it is common for dogs and Great Danes to experience a loss of appetite. During this period, your dog needs to maintain a healthy diet and you should be prepared to take action and make the food more appetizing. Depending on what you normally feed your dog, you can mix up her diet by including more of the things she likes, such as more wet dog food or cooked meats.

man buying pet food
Image Credit: LADO, Shutterstock

How Long Are Great Danes Pregnant?

The average pregnancy for Great Danes is 63 days. But the length varies between individual dogs, and it depends on several factors, including age and size, diet, and overall health. It is common for pregnancy in young dogs to be shorter than for older dogs.

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In conclusion, knowing when a Great Dane goes into heat can be helpful for their owners in providing the best care possible. On average, female Great Danes reach sexual maturity between 10 and 24 months old, and signs of this include vulva swelling, blood-tinged discharge, or mood changes. Female dogs that are not spayed will have estrus cycles throughout their entire lives, so it is important to understand how to properly care for them during these times.

Featured Image Credit: Emma Forsyth 88, Shutterstock

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