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How Long Are Dogs in Heat? Vet Approved Canine Heat Cycle Facts & FAQ

Dean Eby

By Dean Eby

Woman Changing Diaper Of Her Dog

Vet approved

Dr. Maja Platisa Photo

Reviewed & Fact-Checked By

Dr. Maja Platisa

In-House Veterinarian, DVM MRCVS

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

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Canine mating and reproductive cycles are quite different from our own. For starters, dogs are only pregnant for nine weeks before giving birth, compared to nine months for humans. Additionally, dogs go into heat and this is when they’re receptive to mating and fertile. This is different from a period, though still similar in the sense that it brings along a lot of hormonal changes.

During this time, dogs can bleed, urinate more frequently than normal, act nervous, have swollen parts, and more. It doesn’t sound like much fun, so how long does this last, and is this something your dog will have to go through for their entire life? How long are dogs in heat? How often do dogs go into heat? By the end of this article, you’ll have the answers to all of these questions, keeping you prepared for your dog’s reproductive cycle.

Dogs go into heat approximately every six months. A dog’s heat cycle typically lasts 2 to 4 weeks.

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How Often Do Dogs Go Into Heat?

Once your dog begins their heat cycles, you can expect the process to repeat approximately every six months. Of course, this is for the average dog; actual times can vary immensely. The smallest breeds can go into heat more often than others. For these breeds, the heat cycle can occur up to four times each year. Big breeds are on the other side of the spectrum, only going through heat once every 12–18 months. This will continue for your dog’s entire life, though as your dog gets older, the frequency may decrease while the time between cycles grows.

What Age Do Dogs Start Going into Heat?

Depending on what breed your dog is, they could experience their first heat cycle at different times. Small breeds sometimes go into heat for the first time at just four months of age. That said, the average for most dogs is about six months. Large breeds are often on the opposite end of the spectrum, though. For these bigger breeds, the first heat cycle might not begin until the age of 18–24 months.

How Long Is a Dog’s Heat Cycle?

When your dog is in heat, it can be a bit of a difficult time. You’ll have to deal with messes to clean up and any male dogs in the vicinity will likely be going crazy. Luckily, you won’t have to deal with these concerns for long. For most dogs, the heat cycle lasts about 2–4 weeks. In the beginning, she will not be receptive to males, though some dogs are receptive from the start of heat until the end. You’ll know when your dog’s cycle has ended because the bleeding and discharge cease, and male dogs are no longer as attracted to her.

Should You Breed Your Dog?

We can all agree that puppies are super cute. However, they do grow up too quickly. A very important and complex question remains: should you breed your dog at all? Today, animal shelters are overpopulated and overwhelmed with abandoned and unwanted dogs, many of whom get put to sleep or spend their whole life in a small cage, not being able to express their normal behavior or have a fulfilled life. By breeding dogs, we may contribute to this issue of pet overpopulation. Before breeding your dog, consider this crucial ethical aspect, as adopting another dog or a puppy will bring equal joy to your home, and you can make a life-changing difference to that poor pooch.

When Can You Start to Breed a Dog?

If you do decide to breed your dog, speak to your vet first to ensure she is fit and healthy for maintaining a pregnancy. If she has any health issues that may be heritable, she should not be bred, as these will be passed onto her puppies. There are certain breed-specific blood tests and evaluations, such as hip and elbow scores and ocular exams, that every dog should undergo before being considered for breeding to ensure they will not put their offspring at risk of any breed-related health issues. This is responsible breeding that ensures the health and welfare of the breed going forward.

Technically, once your dog’s heat cycles start, they’re capable of producing offspring, though it’s not an optimal time to start reproducing. In fact, it’s recommended that you don’t start breeding a dog until after they have completed their second or even third heat cycle. Prior to this point, your dog is not fully mature and developed and may have a silent estrus, meaning the signs of estrus are not clear, and breeding may be unsuccessful. If you find yourself second-guessing the point at which you should begin breeding, you should ask your vet for a professional opinion.

There are no benefits in having your dog experience multiple heat cycles throughout her life if you don’t intend on her having puppies. Spaying female dogs is strongly recommended as it will prevent pet overpopulation on a large scale and will protect your dog against several health issues that they may otherwise be at high risk of developing, such as mammary tumors and pyometra, an infected uterus that may lead to sepsis, irreversible kidney damage, and even death. Dogs that don’t get a clean bill of health shouldn’t be bred, as the resulting litter may have unhealthy puppies, which leads to deteriorating breed health and welfare issues.
Dog sniffing dog in heat
Image Credit: atiger, Shutterstock

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The 4 Stages of the Canine Reproductive Cycle

During the heat cycle, your dog will go through four stages. If you plan on breeding your dog, you’ll need to understand each of these stages and what they mean for breeding. By following these stages, you’ll be able to predict the best times for breeding. This information is also useful if you have a female dog that you want to get fixed. Speak to your vet about the best timing for the procedure depending on the stage of her cycle and how to protect her from an unwanted pregnancy.

1. Proestrus

This is the first stage of the heat cycle, and it lasts for about nine days. Males become highly attracted to females during this first stage, though many females won’t be receptive at this point. You’ll notice that your dog begins discharging some blood, and the vulva swells; your indications are that proestrus has begun.

2. Estrus

This part of the heat cycle lasts for 3-18 days, depending on the dog. During this time, the female is receptive to male interaction. This is the time when females should mate for the best chance of breeding success. You’ll know your dog is in estrus when the discharge decreases and becomes lighter in color.

beagle on estrus cycle
Image Credit: Sigma_S, Shutterstock

3. Diestrus

Diestrus follows after the estrus and usually lasts around 60 days but can be anywhere from 10 to 14 days after the heat. During diestrus, the discharge from your dog has disappeared completely. The vulva has returned to normal size, and the female will not permit any further mating. Once all signs of discharge and swelling have abated, your dog is no longer in heat. During this stage, dogs that have been successfully mated may be pregnant or may experience a false pregnancy. Get your dog checked out by a vet for pregnancy diagnosis and planning or to treat pseudopregnancy if she is not feeling like herself and has started producing milk.

4. Anestrus

Anestrus is the fourth and final stage of the reproductive cycle for dogs. This is the time between heat cycles, which is generally about four months for most dogs but may be anywhere from 60 to 200 days.

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Conclusion

During heat, your dog is going through a lot of hormonal changes, and you have to contend with extra mess and sometimes erratic dogs. Luckily, the heat cycle doesn’t last very long. For most dogs, heat lasts just 2–4 weeks, so you’ve got less than a month when you’ll have to deal with all the headache that accompanies the heat cycle. Then you’ve got six months off until you have to deal with it all again! If you’re not planning on breeding your dog, speak to your vet about the benefits of getting her fixed, as it will prevent her from developing serious health issues going forward.


Featured Image Credit: andriano.cz, Shutterstock

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