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How to Tell When Your Dog Is in Heat

Dr. Mark is a veterinarian. He has been working with dogs for more than 40 years.

Are you going to recognize the signs of heat before this happens?

Are you going to recognize the signs of heat before this happens?

What Does It Mean When a Dog Is In Heat and When Is It Going to Happen?

When we say that your dog is in heat, it means that she is undergoing changes to her body so that she will attract male dogs, get bred, and have puppies.

Your dog will first come into heat when she is still a puppy. With toy breeds it may be as early as four months, but with giant breeds it may not happen until their second year. The first heat cycle is usually kind of mild though, so unless your front door becomes a gathering place for the neighborhood male dogs, you may not even notice your dog's first heat cycle.

Doggie diapers are a way to prevent spotting around the house.

Doggie diapers are a way to prevent spotting around the house.

How Can I Tell If My Dog Is in Heat?

You'll be able to tell if your dog is in heat based on signs like personality changes and spotting.

Personality Changes

The first sign you will notice, long before any physical changes, are a few changes in your dog's demeanor. She may be nervous, shy, more affectionate than usual, or even aggressive. There is really no way to tell how a dog is going to act. As she gets closer to coming in to heat she will have a swollen vulva; some dogs will even have swollen nipples. For about a week before she starts spotting, your dog will urinate every chance she gets when you walk her—this is her way of alerting the other dogs in the area that she will soon be ready to breed.


Your dog will begin “spotting” (having a bloody discharge from her vulva), and when she starts with this stage you will definitely notice. This may be considered the first day of heat. There may be a lot or just a few drops, but it almost always decreases as the time of ovulation approaches (usually one to three weeks after the bleeding starts).

Bleeding in the house is one of the best reasons to get your dog spayed. If you do not want to have her spayed for some reason, doggie diapers are available and will cover her up so that she does not stain the carpet or furniture. The diapers have to be removed every time you take her outside since, if you do not, she will urinate in the diaper and ruin it.

When Should I Allow My Dog to Breed?

Male dogs are going to be attracted to your female from the first day, but it is not until the second to third week of heat that your dog is most likely to be bred—whether you want it or not. The reduced spotting is a sign of ovulation and your best indication of when she will stand to be bred.

This is the time to take her to the breeder. You can plan on the greatest success if you breed her every few days during the time that she will stand and allow a male to mount.

If you do not want to breed your female, it is also the time you need to watch her carefully and keep her away from the male dogs in the neighborhood. She will not be bleeding anymore but will still be able to conceive puppies.

When no one knows the signs of heat...

When no one knows the signs of heat...

Should I Just Get My Dog Spayed?

To avoid all of these symptoms and the hassles associated with a dog that comes into heat, you should have your dog spayed. There is a lot of controversy as to when it should be done, but if you cannot watch your dog and protect her during the first heat cycle, you should have her spayed while still young.

What If I Do Not Spay My Dog?

There are a lot of reasons people choose to keep their female dogs intact. If you are going to show your dog or compete in some agility competitions, having your dog spayed will keep her from being able to participate.

Other people want to breed their female dog and produce puppies when the time is right.

If you choose not to have her spayed, do not plan on breeding her unless you are willing to have her hips and elbows x-rayed to check for dysplasia, and her eyes checked for changed in the retina. The father should also be tested and found free of all genetic diseases.

A lot of puppies die every day at animal shelters because some people allow their dogs to breed when they should be spayed. Make sure that you have a home for the puppies before you get involved in this process.

This article is accurate and true to the best of the author’s knowledge. It is not meant to substitute for diagnosis, prognosis, treatment, prescription, or formal and individualized advice from a veterinary medical professional. Animals exhibiting signs and symptoms of distress should be seen by a veterinarian immediately.

Questions & Answers

Question: I just found my German Shepherd locked onto my rottweiler and do not want her to be pregnant. What can I do to prevent a pregnancy?

Answer: There are several options available but all of them are available only through prescription. You can read to learn more, but you need to call your local vet immediately and ask what method he uses and when he needs you to bring your rottweiler into his clinic.

Comments on December 18, 2019:

EXTREMELY helpful! Thank you so very much for your expertise and caring to share with pet owners who love their pets so much! I'll always check Dr Mark first for helpful advice!

Mark dos Anjos DVM (author) from The Atlantic Rain Forest, Brazil on June 07, 2018:

Normally the male "ties" when he ejaculates, so if you were able to separate them quickly there is probably no problems.

You can contact your local vet and ask him about a "mismate" injection. Not all vets will give it because of the side effects.

You can also wait and have a pregnancy test done later, with a dexamethasone injection if the test is positive. This will cause her to resorb the puppies.

If you do not want her to breed again the best thing to do is have her spayed.

You are correct. If you just got rid of the last litter a month ago it is still too soon to have another litter. Let her body recover for another six months.

Knickie669 on June 07, 2018:

Just found my dogs but they weren’t lock in. Was able to pull them apart and it was less then 15 min should I worry about her getting pregnant also she just finished nursing a month ago

Mark dos Anjos DVM (author) from The Atlantic Rain Forest, Brazil on March 26, 2014:

It varies a lot so I cannot give you a definite answer. One of my Pitbulls just came out of heat, she bled for only 3 days. Most dogs bleed from 7-10 days. Plan on watching her closely for about 10 days after that.

If she is a mix breed, and you have no interest in breeding her in the future, it will make your life a lot easier if you go ahead and have her spayed. When a dog is in heat you have to watch her like a hawk!

It may be better to spay her after the first heat. Do some more reading on the subject.

mindi on March 26, 2014:

Approximately how long does the bleeding with first estrus last? I have a lab mix pup.

Bob Bamberg on September 07, 2012:

That sure makes the pizza delivery guy look boring.

Mark dos Anjos DVM (author) from The Atlantic Rain Forest, Brazil on September 07, 2012:

Yes, that is a funny point because the dogs are all real nice, but around here people are afraid of big dogs. Oh, and the correct answer? A female that likes to visit all the males in the neighborhood.

Bob Bamberg on September 07, 2012:

Well, after lengthy analysis I've ruled out Pug, so that leaves either a bon vivant male Husky or a promiscuous female Husky.

Jeez, I'm only kidding, folks!! In some places sexist humor is OK and in others, it's not. I'm not a knuckle dragger, really!

I'll bet not too many people try to break into your client's property!

Mark dos Anjos DVM (author) from The Atlantic Rain Forest, Brazil on September 07, 2012:

Big cultural difference! There is not even a place to spay a dog around here, even if she shows up one day in fishnet stockings! I was training at a home yesterday with a Husky/lab cross, a Husky/German Shepherd cross, and a Husky/Alaskan Malamute cross. Guess what her first dog was?

Bob Bamberg on September 07, 2012:

Interesting and informative hub, DrMark. I've never owned a dog, so I always thought the first sign was fishnet stockings under a leather mini-skirt. Now I are enlightened :)

Around here, owners (unless they are serious breeders) who don't get their dogs spayed or neutered during puppyhood are looked upon with some scorn. There is some serious social pressure exerted.

Most pet adoption organizations, if they haven't already had the surgery done, require a commitment to do so (sometimes an actual appointment date) before they will release a dog to an adopter.

Interesting read, as usual. Voted up and interesting. Regards, Bob