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How to Know a Dog is Ready to Mate

Ashley Bates

June 13, 2021

dog sniffing ready to mate

It’s one of Mother Nature’s most cruel jokes: A dog that escapes from their home will become pregnant in seconds, but one that you’re trying to breed will take dozens of attempts before anything happens.

While that’s certainly frustrating, it turns out that most unsuccessful breeding attempts are due to starting before the dog is ready. Of course, that means that in order to be successful, you’ll need to learn the signs that your dog is ready to mate.

To do that, you’ll need to read this guide.

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Males vs. Females

Dog kissing

Not to contribute to tired old stereotypes, but male dogs are almost always ready to go. All it takes is the scent of a female in heat to get their motors running.

Therefore, all of these tips are reserved for female dogs. These are all ways to tell if your dog has gone into heat, so you can start the breeding process on the right foot.

If you try to breed your dog before she goes into heat, not only will you be unsuccessful, but she might also be aggressive toward the males. This could create negative associations with the whole process, making it difficult to be successful when she does go into heat.

Also, you should always wait at least two heat cycles before trying to breed a sexually mature dog. This will make her much less likely to experience a problematic pregnancy.

The Four Stages of the Canine Heat Cycle

You should know the stages of the canine heat cycle before you even start trying to breed your pooch. This knowledge will prepare you for what to expect at any given point and enable you to time the breeding efforts for greater success.

The four stages of the canine heat cycle are the following.

1. Proestrus

This is the beginning of the heat cycle. At this point, your dog’s estrogen levels will start to peak and follicles will develop in her ovaries. Proestrus can last anywhere from 0-27 days, but it usually lasts around 9, on average.

Once your dog is in proestrus, males will take an interest in her. However, females aren’t receptive at this time and often react with hostility to the male’s approach.

Signs that your dog has reached proestrus include a swollen vulva, bloody discharge, excessive licking of the genitals, clingy behavior, and of course, aggression toward males. The animal may also hold her tail close to her body to ward off unwanted advances.

2. Estrus

This is the phase in which the magic can happen, as your dog will become fertile at this time. It lasts around 9 days on average but can also take as long as 24 or as few as 4 days. Estrogen levels are dropping and progesterone levels are rising during this time.

Aggression toward males will usually disappear when estrus starts, and your dog will be more welcoming to their advances. However, she may become hostile to other females at this point.

Signs to watch out for that estrus has begun include a slowing of vaginal discharge, increased urination, and marking spots to indicate her readiness to breed. If a male is present, she’ll likely approach him with her tail to the side rather than tucked close to the body.

Beagle on estrus cycle
Image Credit: Sigma_S, Shutterstock

3. Diestrus

When diestrus begins, your dog’s heat phase is over, and she’s no longer fertile. It’s at this point that her body has to either begin to return to normal or start developing into pregnancy. Progesterone levels will drop regardless of whether the breeding was successful.

Her behavior toward males will likely return to its baseline, as she’ll likely be neither welcoming nor overly aggressive. She’ll also likely cease being overly aggressive to other females.

Her vulva will return to a normal size, and any discharge will cease. Diestrus will last about two months.

4. Anestrus

There is about a 4-month gap between diestrus and the start of proestrus; this gap is called “anestrus.” This is a “normal” period for your dog, as she won’t suffer from discharge, her behavior toward other dogs will level off, and her vulva won’t be swollen.

While everything looks calm on the surface, your dog’s body will be preparing her uterus for the start of the next heat cycle.

How to Tell If Your Dog Is in Heat

To recap, here are the seven ways that your dog’s body will alert you to the fact that she’s in heat and ready to breed:

  • Her vulva becomes swollen.
  • She becomes receptive to male dogs after a period of aggression toward them.
  • She has bloody discharge from her vulva.
  • She’s begun licking her genitals excessively.
  • More frequent urination begins to occur.
  • She appears agitated or nervous, or aggressive toward other females.
  • She no longer holds her tail close to her body.
Voltgroup_shutterstock_breeding
Image Credit: Voltgroup, Shutterstock

What to Do If Your Dog Is in Heat

If you have plans to breed your dog, now is the time to do it. You’ll have a limited window during with estrus occurs, so don’t delay.

Breeding is only one small part of your dog’s life at this time, though. You’ll also have to deal with them the rest of the time, and with that comes certain issues that are unique to a dog in heat.

Your pup will have a strong urge to roam and find a mate. As a result, you shouldn’t leave them outside unattended, and you should analyze your fence for any signs of weakness. Never let your dog off-leash while they’re in estrus, or else you may never see them again.

While you’re making sure your dog can’t get out, be sure that other dogs can’t get in either. A male dog’s desire to mate is a powerful thing, and they can be capable of amazing feats when there’s a female in heat around.

This is a good time to update your pup’s ID tags and microchip information if you haven’t done so recently, as your dog is at a higher risk of getting lost at this time than any other.

Some dogs can experience health issues while in heat, so keep your vet apprised of the situation and don’t hesitate to contact them if you feel that something is wrong. Also, if you’re done breeding your dog — or if you don’t plan to breed her at all — you should spay her once her heat cycle is complete.

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Good Luck Making Puppies!

There’s nothing quite like a newborn litter of puppies, so we can understand your desire to breed your dog. Breeding isn’t as simple as it seems, though, so unless you know what you’re doing, it can be a long, drawn-out, and frustrating process.

We hope that this guide has made it easier for you to determine when your dog is in heat so you can start the breeding process at the right time.


Featured Image Credit: High Simple, Shutterstock

Ashley Bates

Ashley Bates is a freelance dog writer and pet enthusiast who is currently studying the art of animal therapy. A mother to four human children— and 23 furry and feathery kids, too – Ashley volunteers at local shelters, advocates for animal well-being, and rescues every creature she finds. Her mission is to create awareness, education, and entertainment about pets to prevent homelessness. Her specialties are cats and dogs.

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