Heat, or estrus, is a normal biological process that intact female dogs go through as part of their reproductive cycle. Just like human females experience menstruation, female dogs go into heat. It occurs when the female dog’s reproductive system matures and she becomes receptive to mating with males.
What Happens During a Female Dog’s Heat Cycle?
A female dog’s heat cycle occurs in four stages:
Proestrus
This is the first stage when the female dog’s vulva begins to swell and she starts bleeding from her vagina. This bloody discharge lets male dogs know she is getting ready to mate. Proestrus can last anywhere from 4 to 20 days.
Estrus
During estrus, the female dog is now receptive to breeding with males. Her discharge lightens in color and she will “flag,” or hold her tail off to the side, to signal to males that she is ready to mate. This stage lasts about 5 to 10 days.
Diestrus
After breeding, the female dog enters diestrus, during which her vulva returns to normal size and she will no longer be interested in mating with males. Diestrus can last 60-90 days in dogs.
Anestrus
Anestrus is the resting phase when the female dog’s reproductive system shuts down before the next heat cycle begins. This stage can last anywhere from 2 to 10 months.
The intervals between heat cycles are different for each dog but on average they go into heat every 6 to 8 months. Some dogs can cycle as early as every 4 months while others may go into heat just once a year.
What are the Signs of Heat in Dogs?
Here are some of the most common signs that your female dog is in heat:
- Swollen vulva
- Bloody discharge from the vagina
- “Flagging” – holding tail off to the side
- Increased urination
- Excessive licking of genital area
- Behavior changes – nervousness, irritability, restlessness
- Attracting male dogs
If this is your dog’s first heat, these signs will become very obvious as it progresses. In subsequent heats, the symptoms may be less intense.
How Long Does a Dog’s Heat Cycle Last?
On average, a dog’s heat cycle lasts about 3 weeks from start to finish. However, each phase can vary in length, so the total cycle may range from 2 to 4 weeks. Here are some general time frames:
- Proestrus: 4 to 20 days
- Estrus: 5 to 10 days
- Diestrus: 60 to 90 days
- Anestrus: 2 to 10 months
The estrus phase when the female is receptive to breeding is usually the shortest part of the cycle. Interest in mating and the bloody discharge taper off as she transitions into diestrus.
Do Female Dogs Bleed a Lot When in Heat?
The amount of bleeding during a female dog’s heat cycle varies, but it is generally not an abnormal amount of blood loss. The bloody vaginal discharge may be light pink or a brighter red color.
Some swelling of the vulva and spotting of blood drops may also occur. You may see some blood on your dog’s bedding, on the floor, or on her back end. The bleeding tends to decrease once the female dog enters the estrus phase.
If you notice large volumes of blood loss or bleeding that lasts more than a month, consult your veterinarian. Extended or excessive bleeding could signify a health problem.
Is it Normal for a Female Dog to Lick Her Private Area During Heat?
Yes, it is very normal behavior for a female dog to excessively lick her genital region when she is in heat. The bloody discharge and swelling of the vulva can cause irritation and discomfort. The licking is your dog’s way of attempting to soothe those sensations.
It is best not to try to inhibit this behavior too much. Just redirect her gently when the licking becomes obsessive. Provide plenty of other activities to distract her. The urge to lick should subside as the heat cycle ends.
Why Does My Female Dog’s Vulva Look Swollen?
As your female dog goes into heat, one of the first physical signs is swelling and enlargement of the vulva. This occurs as her body is preparing for conception and the vulva tissue becomes engorged.
The swollen vulva lets male dogs know through smell and appearance that she is getting ready to mate. The size of the vulva will reduce again once the heat cycle ends and hormone levels return to normal.
If the vulva remains enlarged outside of your dog’s heat, have your vet examine her to rule out any infection or medical issues.
Why Does My Dog Urinate More When in Heat?
Frequent urination is very common in female dogs having their heat cycle. The hormones that her body produces during this time can cause incontinence and a near constant urge to urinate.
You may notice your dog asking to go outside more and having accidents in the house despite being house trained. This is typical behavior and understandable given the hormonal influences.
Be patient and allow her to urinate frequently. The increased need to pee will resolve after she goes out of heat. Consider putting pee pads by the door to make those frequent potty trips easier on both of you!
What Age Do Female Dogs Go Into Heat?
On average, most intact female dogs will have their first heat cycle at around 6 months of age. However, the age varies greatly depending on the breed and size of the dog:
- Small breeds – 4 to 12 months
- Medium breeds – 6 to 15 months
- Large/giant breeds – 9 to 24 months
So a smaller female dog like a Chihuahua can go into heat as early as 4 months, while a Great Dane may not have her first heat until 24 months of age. Monitor your young female dog and look for physical and behavioral signs when she’s approaching maturity.
Are Female Dogs Moody During Their Heat?
Behavior changes are common when a female dog is in heat. The surge of hormones can cause moodiness, irritability, nervousness, and restlessness.
Your formerly affectionate and playful pet may become withdrawn and uninterested in interaction. Or she could become clingy and anxious, following you everywhere.
Try to be patient and understanding during these behavior changes. Avoid scolding or disciplining your dog for snapping or acting out of character. The moodiness is temporary and her normal demeanor will return after the heat cycle finishes.
Do Female Dogs Bleed When In Heat While Pregnant?
Pregnant dogs do not have a normal heat cycle during gestation. So a female dog that is pregnant will not bleed from her vulva during this time. Any discharge indicates a problem with the pregnancy.
Some bleeding immediately after mating is normal. But bloody or abnormal discharge during the roughly 63 days of canine pregnancy could mean:
- Miscarriage
- Resorption of fetal tissue
- Infections like pyometra or brucellosis
Contact your vet if your pregnant dog shows vaginal discharge, lacks appetite, or is feverish, lethargic, or straining. These require prompt veterinary care.
Is it Normal for My Dog to Not want to Walk When in Heat?
It’s not unusual for a dog in heat to be reluctant about going on walks. The vulvar swelling and bloody discharge make urination uncomfortable. The pressure on her inflamed vulva also makes movement painful.
Try shorter, slower paced walks and be patient if your dog needs frequent potty breaks. Providing puzzles, chew toys, and training games can fulfill her exercise needs while her vulva heals.
If lethargy, lack of appetite, vomiting, or crying from pain occur, have your vet examine her. There may be a urinary tract or uterine infection causing more severe discomfort.
How Often Do Female Dogs Go Into Heat?
On average, female dogs go into heat twice per year. Their heat cycles usually come at intervals of 6-8 months.
However, this can vary depending on the individual dog. Some small breeds that mature faster may go into heat every 4 months. Older or inactive dogs may only cycle once a year.
While in heat every 6 months is considered normal, have your vet assess your dog if her cycles become more frequent or farther apart. Hormonal disorders can cause irregular heat cycles.
Do Spayed Dogs Still Go Into Heat?
No, spayed dogs can no longer go into heat. Spaying or neutering refers to the sterilization procedures that remove the reproductive organs of dogs.
In females, spaying involves removing the uterus and ovaries through abdominal surgery. Since the ovaries produce the hormones that control the reproductive cycle, females without ovaries can no longer go into heat.
However, keep in mind that it takes about a month or two for remaining hormones to dissipate after surgery. So she may exhibit some heat behaviors during this transition.
Can Female Dogs Get Pregnant While Still Bleeding?
Yes, a female dog can get pregnant during the bloody diestrus period of her heat cycle.
Although less fertile than during estrus, dogs can still conceive for a short window during diestrus right after going out of heat. Sperm can remain viable in the female reproductive tract for up to a week.
If you do not intend to breed your dog, keep her safely confined away from male dogs for a month until her heat cycle finishes completely. Consult your vet about spaying to avoid unwanted litters.
When is the Best Time to Breed a Female Dog in Heat?
| Heat Cycle Stage | Best time to breed |
|---|---|
| Proestrus | Not ideal, very low fertility |
| Estrus | Days 10-14 offer highest fertility rates |
| Diestrus | Can still conceive right after heat, but fertility rapidly declines |
| Anestrus | Cannot get pregnant |
The estrus period is the optimal time for breeding since progesterone levels peak and the female dog is ovulating. Specifically, days 10-14 of the heat offer the best fertility rates.
Work with your vet to track your dog’s cycles for the best timing. Breeding too early or late in the heat lowers chances of conception. Consider performing artificial insemination for the highest success.
What Age is Best to Breed a Dog?
Here are the recommended breeding ages for female dogs based on size:
- Small breeds – After 3rd heat cycle, around 1.5 years old
- Medium breeds – After 3rd heat cycle, around 2 years old
- Large/giant breeds – After 3rd heat cycle, around 2-3 years old
The first couple of heat cycles are for the female dog’s physical maturity. Wait until at least the 3rd heat to breed her, or when she reaches the ideal breeding age for her size.
This allows the female to fully grow and lowers risks of complications. Breeding too young can harm the dam and her litters. An older dog also tends to be a more attentive mother with stronger maternal instincts.
How Often Should You Breed a Female Dog?
Responsible breeders limit a female dog to producing just 1-2 litters per year. Back-to-back litters or breeding more frequently than this is taxing on the mother.
Ideally, a dog should only have a maximum of 4-5 litters altogether in her lifetime. She should also be given at least 1-1.5 years between pregnancies to recover before the next breeding.
Overbreeding or not allowing proper rest between heats can lead to uterine infections, fatigue, and low milk production. It shortens the female dog’s lifespan and harms puppy health.
Can Dogs Mate if Not in Heat?
No, dogs cannot successfully mate if the female dog is not in heat.
Female dogs are only receptive to breeding while in the estrus phase of their reproductive cycle. Outside of heat, they will not allow mating to occur.
Male dogs may still show interest and mount a female when she’s not in heat. But penetration does not take place since the vulva remains closed tightly. Pregnancy cannot occur without a true tie during the female’s estrus period.
Can a Dog Get Pregnant Without a Tie?
It is highly unlikely for a female dog to get pregnant without a copulatory “tie” taking place during mating.
The tie occurs when the male dog’s bulbus glandis, an enlarged area of the penis, swells after penetration and the dogs remain “stuck” together. It ensures semen remains inside the female’s reproductive tract.
Pregnancy may rarely happen without a full tie but the chances are extremely low. The tie ensures sperm is deposited as close to the cervix as possible for ovulation.
Can a Dog Get Pregnant Right After Giving Birth?
Dogs can get pregnant again shortly after delivering a litter. This can happen because:
- Female dogs go into heat 2-3 months after giving birth
- Nursing does not necessarily prevent conception
- Some female dogs even go into heat when pregnant
To avoid back-to-back litters, keep the female dog away from intact males for at least 2-3 months after she gives birth. Let her body fully recover before breeding her again.
Consult your vet about when it’s safe to breed after her litter. Most recommend waiting until the next heat cycle to allow the uterus to return to normal.
Conclusion
A female dog’s heat cycle is a normal biological process indicative of her ability to reproduce. As an owner, it is important to recognize the signs of heat and understand how the cycle works. Know when to expect your dog’s first heat, how long it lasts, and what behavior changes may occur. Discuss any concerns with your veterinarian and take steps to avoid unwanted litters through early spaying or carefully monitoring heat cycles. Being informed about what heat is in female dogs leads to better health and wellbeing for your beloved pet.