Dog Heat Cycle and Breeding

Updated August 23, 2021
Mommy dog takes care of her pups

When is the best time to breed a dog in heat? It may seem as though dogs can turn up pregnant in the blink of an eye, but it's actually a fairly complicated process. Just ask any breeder who has repeatedly tried and failed to produce a litter from their champion female dog -- sometimes, things just don't go according to plan. Successful dog breeding is all about the timing, so take a closer look at the biological issues behind the process.

Dog Heat Cycle Indicates When to Breed


Simply put, estrus is a female dog's fertile time, generally referred to as a heat cycle or "season." The first heat cycle typically takes place between 6 and 9 months old, but breeds that mature more slowly may not experience a first heat until 12 to 18 months of age.

Cycle Length

A normal canine heat cycle lasts approximately three weeks, during which time the dog will release a discharge that contains blood. There are numerous signs and symptoms that indicate when a dog is in heat. In the initial stage, known as proestrus, a female dog's vulva begins to swell, and you may notice them licking themselves more than usual. Male dogs will also begin sniffing them more when their hormones produce a scent that signals they are ready to breed.

Dog Heat Cycle Chart

Weeks of Heat Heat Stages, Signs, and Symptoms
Week One Once the vulva begins to swell, the female dog will begin to produce a bloody discharge. The amount will vary from one dog to the next, so it may or may not be noticeable.
Week Two Sometime around nine to 12 days, the color of the discharge lightens to a pinkish-tan color. It's usually around this time, referred to as estrus, that the vulva softens and eggs are released from the ovaries. At this point, you may notice your female dog flirting with other dogs; this is a sign they are ready to accept a stud dog's advances.
Week Three If the female's heat cycle is allowed to continue uninterrupted, the discharge begins to look bloody again by the third week. The amount will trail off until the cycle has concluded with anestrus.

Yearly, Bi-Yearly, or Quarterly Cycles

On average, a healthy intact female dog comes into season every six months. However, this can vary -- some dogs only cycle once a year, while others come into season on a quarterly basis. Quite often, female dogs that experience heat quarterly are not fertile every season.

Signs That It's Time to Breed

So, when is the best time to breed a dog in their heat cycle? Look for these signals that your dog is ready to be bred:

  • General flirty/affectionate behavior
  • Tail held high and flagging
  • Pushing up their rear when petted on the back
  • Willingness to stand and present vulva
  • Color change in discharge from red to pinkish-tan

How to Track a Dog's Heat Cycle

While you cannot predict the exact day or even week when a dog will come into their heat cycle, there are ways to track it and obtain a general idea of when it can occur. On the first day that your dog comes into heat, use a calendar to count out the next eight to 10 days -- this will comprise their complete cycle. From there, use the calendar to track out the next five to eight months. Months five, six, and seven are times when your dog may come into heat.

Unfortunately, you'll need to track your dog's heat cycles for some time before you can get an understanding of their normal pattern. It's also possible to determine how close a dog is to their heat cycle using hormone testing, but this can be cost-prohibitive, as you will need to do it regularly to establish a pattern. Another option is to use a dog heat cycle calculator app, such as The Puppy Planner, which is available for iOS and Android devices.

The Dog Mating Process

Breeding usually takes place naturally, without any human intervention, beyond introducing the potential dam to the stud. However, a little direction may be required if one or both of the dogs involved have never been bred before.

  • Typically, the male dog will become very excited when introduced to a receptive female dog and will begin sniffing and licking at their vulva. Very quickly, they will mount from behind and begin to thrust.
  • When all goes as nature intended, the stud will penetrate the female dog's vulva; this causes two glands directly behind the penis to swell considerably.
  • In response, the dog's vulva will clamp around this swelling, which is referred to as a tie, the moment when the dogs become "stuck" together.
  • This period typically lasts from 15 to 30 minutes, and it is at this point that sperm are being delivered to waiting eggs.

If the mating has been successful and the female dog conceives, they will deliver pups between 58 and 63 days later. You can easily find your dog's due date by consulting a canine pregnancy calendar.

Best Time for Mating

There's no specific way to determine when ovulation will occur in a home setting. Usually, your dog will be most fertile between nine to 10 days after they entered heat, and can remain fertile for up to five days. According to VCA Hospitals, the most common sign is the color of the discharge, which becomes more of a pink, "salmon" color rather than blood red. You can also take your dog to the vet to have serum progesterone tests performed, which can give you insight into when the best time for mating is, but it does require you to take your dog for a series of tests every day or every other day during their cycle. DIY testing kits are available for purchase, as well, although they may not be as reliable as the tests performed by your veterinarian.

Age and Mating

A dog can breed the first time they go into heat. However, a responsible breeder will have important criteria in mind before allowing a dog to be bred. According to the American Kennel Club, you may not register any litters from a dam younger than 8 months or older than 12 years. In addition, they strongly recommend that breeders consider several factors not related to age before breeding. Prospective breeders should ask themselves the following questions.

  1. Are you ready to have a litter? This includes not only knowledge of the process, but having the equipment and supplies, such as a proper whelping box, a quiet place for your dam, and the ability to care for them and the puppies.
  2. Will your dog further the breed? AKC advises against "kennel blindness." If your dog has medical, behavioral, or other genetic flaws, you do not want to pass these on. Likewise, have you chosen a male dog that is also worthy of being bred and can further the good qualities of the breed?
  3. Are you ready for the expense of the many pre-breeding health checks and tests you should perform before breeding a dog, such as Orthopedic Foundation for Animals testing and a polyneuropathy DNA test? If something goes wrong during the pregnancy, can you financially afford additional veterinary services such as a C-section, which can cost up to $5,000?
  4. Are you committed to the time and expense of caring for a pregnant dog, the newborn puppies, as well as interviewing prospective homes and placing the dogs responsibly? This may include agreeing to take any of the dogs back in the future if something happens at their new home and the owners cannot care for them any longer.

Time Will Tell

Once breeding has been completed, it will take some time to find out if it was a success. You'll be able to tell if a litter is on the way a lot sooner if you learn to spot the signs of pregnancy.

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Dog Heat Cycle and Breeding