How long do dogs bleed in heat?

Puberty or sexual maturity in the female dog usually occurs around nine or ten months of age. Smaller breeds tend to go into estrus or 'heat' earlier, even as early as four months of age in some females, while in large and giant breeds, it can take up to two years. For many dogs, the first heat is 'silent' or does not have clinical signs associated with estrus. Additionally, many dogs' first estrus cycle is unlikely to allow successful breeding, therefore the standard practice is to wait until the second or third heat cycle before breeding.

How often do female dogs come into estrus?

On average, estrus occurs about twice a year, although it varies from dog to dog. Small breeds tend to cycle more regularly than larger breeds. The interval between heat cycles tends to be four to twelve months with an average of seven months. An exception is the Basenji and other sled dog breeds, as they tend to go into heat only once per year, typically in the spring.

What are the signs of estrus in dogs?

Vulvar swelling is the first physical indication of an impending estrus cycle. However, the most obvious recognizable sign is vaginal bleeding. This may not become apparent until a few days after the female has come into estrus. Some female dogs experience heavy vaginal bleeding during estrus, while other dogs have minimal bleeding. If you are concerned about your dog, consult your veterinarian.

"...the most obvious recognizable sign is vaginal bleeding."

From the beginning of a female’s estrus period, she will be attractive to male dogs, though she will usually not be receptive or allow mating until seven to ten days into her cycle. As the cycle progresses, the color and appearance of the discharge change. In the beginning, it is usually quite bloody and thick in appearance, then gradually changes to a watery, blood-tinged discharge. The receptive period for mating usually corresponds to this change in the appearance of the discharge.

You may also find your female dog is passing small quantities of urine more frequently. The urine contains pheromones and hormones, both of which signal interested males that she will be receptive soon.

How long does an estrus cycle last?

Cycle length varies, averaging two to three weeks for most dogs. The cycle begins with the first signs of vulvar swelling or vaginal discharge. It ends when all discharge ceases and the vulva has returned to its normal size.

How do I determine the best time to mate my dog?

This can be difficult. Most dogs ovulate and are receptive around the eleventh day of estrus. The discharge is usually less bloody (often described as a salmon color) and the female will be actively looking for a male. The female may stand and present her hind end for the male to be mounted or she may tuck her tail to the side. However, ovulation may occur either early or late during the heat cycle.

Are there any tests to determine when to mate my dog?

Yes. There are two simple tests that your veterinarian can perform:

1. Vaginal cytology or vaginal smears. A simple microscopic examination of vaginal cells will detect changes in cell appearance and numbers. This technique has been used for many years and is reasonably reliable. It is non-invasive and does not cause discomfort to the female. Most vaginal smears are performed over several days to look for changes in the cells that predict ovulation and the best time for breeding.

2. Serum progesterone test. This test measures the progesterone level in the blood. It is very sensitive and has become popular due to its accuracy. Some dogs will require several tests done over a series of days to predict ovulation. Some veterinarians prefer another daily blood hormone test, LH (luteinizing hormone), instead of serum progesterone. Your veterinarian will discuss the different testing options and which is best for your dog.

"The serum progesterone test is a good indicator of when mating is most likely to be successful."

Your veterinarian may be able to perform both tests at the clinic, though sending samples out to a laboratory provides more accurate results. The serum progesterone test is a good indicator of when mating is most likely to be successful. It is useful for females with a history of unsuccessful mating or females who will be traveling a considerable distance to the male dog.

What can I do to ensure mating is successful?

Surprisingly, male dogs appear to be more stress-sensitive than females during mating. Successful matings are more common when the male dog is in his own environment. For this reason, females are usually taken to the male dog's home for breeding.

The time of mating is extremely critical, and it is highly recommended to have your female tested to determine the optimal days for breeding. For most females, the best time for breeding is between the tenth and fourteenth day of estrus. However, some females ovulate as early as the third or fourth day or as late as the eighteenth day.

It is normal to arrange for two matings (also called stud services) for your dog, often 24 to 48 hours apart. Check these details with the owner of the male when making initial inquiries. Also, be sure to ask what will happen if your female dog does not become pregnant as a result of the stud service. It is common for the owner of the male dog to offer a free service next time.

I was told that my female had tied well with the dog. What does this mean?

During coitus, part of the dog's penis (bulbis glandis) swells and enlarges. The female's vaginal muscles contract against the bulbis glandis, preventing the penis from being withdrawn. This is the 'tie' that is considered a desirable feature of successful mating. It is important to note that pregnancy can occur without a tie. Once tied the male dog will often step over the female or be turned by handlers into a position so that the dogs are back-to-back. The tie will usually last for five to ten minutes.

What should I do if I find my dog tied to another during a mismating?

There is little point in trying to separate animals that are locked together in this way. Buckets of cold water, water pistols, cap guns, and so forth do little to speed up the process of separation and merely upset or potentially injure the dogs. In fact, forced separation can result in serious injury to the female and should be avoided. If a mismating occurs, consult your veterinarian as soon as possible so your options can be reviewed.

A dog's typical heat period with bleeding will last two to four weeks. The complete heat cycle happens in about five to seven months. There are four phases to the heat cycle, each with its own symptoms and behaviors. Bleeding or bloody discharge occurs in two of the four phases. Though dogs know what to do during each other heat cycles, they could need extra care from a human to keep their discharge from getting on the furniture or to handle an issue like a uterine infection.

A dog's heat cycle refers to the time when a dog is fertile and ready to mate.

Look for These 7 Signs That Your Dog Is in Heat

During your dog’s complete heat cycle, she will experience four phases. A typical heat period lasts roughly two to four weeks, with a pregnancy or resting phase following the estrus period. Knowing what to expect will help prepare you and your dog for any abnormal behaviors or problems during her heat cycle. As your pooch progresses through her cycle, you will notice these four stages:

1. Proestrus: Proestrus is the start of the heat period where your dog’s body is preparing to mate and averages about nine days, but can last from three to 17 days. Her vulva will swell and you may notice a blood-tinged discharge, but many dogs are fastidious about messes and will clean themselves before you notice. Your dog may also hold her tail close to her body and stick just as close to your side, displaying clingy behavior. At this stage of the heat cycle, your dog will attract males, but she will not be receptive to them and may become aggressive if they try to mount her.
2. Estrus: The estrus phase is the mating phase and usually lasts around nine days, but can be as short as three or as long as 21 days. During this time, blood flow will lessen and then stop, but the discharge may change to a straw color. Female dogs will attract and accept males, with ovulation occurring two to three days after mating. You may notice your dog urinating more frequently and marking spots within and outside your home to spread pheromone messages indicating her readiness to breed. If an intact male is present, your female dog is likely to present herself to him, hindquarters first, and with her tail held to the side.
3. Diestrus: This phase occurs directly after the “in heat” stage and lasts for about two months. Her body will proceed with the pregnancy or return to rest, as her vulva returns to normal size and the vaginal discharge disappears.
4. Anestrus: Anestrus is the uterine repair phase, in which no sexual or hormonal behavior is present, and can last for anywhere from 90 to 150 days before the next proestrus stage begins.

The Spruce / Melissa Ling

The only option to prevent your dog from going into heat is to have her spayed. Spaying is highly recommended for all female dogs unless you plan on strengthening the breed. Once your dog is spayed, she will have a reduced risk for mammary cancer and will be unable to contract uterine infections or go through a heat cycle.

You can have your dog spayed while she is going through her heat, but the surgery is more complex. Speak with your veterinarian about the best time to spay your pet.

• The age at which a dog experiences her first estrus varies greatly between breeds. Toy and small breeds mature much earlier than giant breeds and can come into heat as early as four months of age. Giant breeds may be two years old before they experience their first heat.
• On average, a female dog will come into her first heat between six and 15 months of age.
• Most dogs have two estrous cycles per year.
• Male dogs will be attracted to a female dog entering her heat cycle before she is receptive. Watch for defensive aggression that warns males to back off.
• Remember—just because your dog is no longer bleeding, does not mean she can no longer get pregnant. She’s much more likely to let a male mate immediately after the bloody discharge stops.
• Dogs can get pregnant during their first heat cycle, but this is not advisable as a six-month-old dog is not yet fully grown/mature, and complications for the mother and the puppies are more likely.
• Ideally, a female dog should have two normal heat cycles before being bred.
• To prevent a possible pregnancy while your dog is in heat, keep her separated from male dogs for at least three to four weeks after the first sign of bleeding.

What to Expect When Your Dog is Pregnant

If you suspect your pet is sick, call your vet immediately. For health-related questions, always consult your veterinarian, as they have examined your pet, know the pet's health history, and can make the best recommendations for your pet.