Dogs In Heat: What To Look for?


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If you are a dog owner planning on breeding your dog or are just curious about dogs in heat and what to expect, you are not alone. You should be aware of things with dogs in heat so you can best prepare for what’s to come.

There are several things to look for when a female dog is in heat, but what? A female dog in heat can have more aggressive behavior, low energy, and different positions when peeing or peeing more often.

This article will discuss the heat cycle and what it means for you and your dog. I will also go through what to look for and do to prevent or encourage pregnancy. It will do most owners a world of good to understand what their dog is going through.

What Does it Mean if a Dog is in Heat?

Simply put, when an unaltered female dog is “going into heat” or “in heat,” her body releases mating hormones and is open to reproducing. When female dogs are in heat, the possibility of a pregnancy is high if a male dog is around.

It’s always best to be prepared so you can either avoid that potential pregnancy or welcome a litter of puppies. Just another part of being a dog mom!

Heat is a Cycle

There are four stages of a heat cycle in female dogs. Her chances of pregnancy increase as the cycle progresses.

The Proestrus Stage

This is the first stage. In this first heat cycle of female dogs, you may notice a swelling of her vulva, which can last between 3 to 17 days. When female dogs are in the proestrus stage, she is actually pretty resistant to male dogs. You may notice her doing frequent tail tucking and changes in her appetite and personality. A dog will keep her tail close to her behind unless she is in active heat.

The Estrus Stage

The estrus cycle or estrus phase is when your dog’s natural inclination to follow her breeding instinct kicks in. Her eggs are released from the ovaries during this stage, as she is most fertile and the most willing to entertain male company. This is the main part of the reproductive cycle.

You will notice that she is raising her behind toward any nearby male dogs to indicate she is open to mating. She can remain in the estrus cycle or estrus stages for another three to 17 days.

The Diestrus Stage

This is the stage where your dog’s heat cycle will start to end. If she is indeed pregnant, this stage will last until her pups are born. Her vaginal swelling will decrease, and her attention to male dogs will decrease. Her vulva will also return to normal size.

The Anestrus Stage

Also known as the resting stage or inactive stage, the anestrus stage is between 100 to 150 days, which is the period of rest or inactive phase before she goes into heat again.

When Can I Expect the First Heat Cycle? 

Most dogs reach sexual maturity around nine or ten months, with smaller breeds going into heat as early as four months old. For very large breeds, a first heat can take up to two years.

A dog’s first heat is silent and has no clinical signs. It is also unlikely to be successful in the attempts of a pregnancy. Therefore, most breeders will wait for a dog’s second heat before breeding them.

How Often Do Dogs Go into Heat?

On average, dogs will go into heat about every six months or twice a year. However, the breed and size of the dog will affect how often a dog goes into heat. Smaller dogs tend to go into the dog heat cycle more often than large dogs, and some large and giant breeds may only go into heat once every 12 to 18 months.

Dog Breeds With Longer Heat Cycles

As explained above, giant breeds tend to go longer between cycles. So let’s take a look at some of the breeds that fall under that category. You can ask your veterinarian if your dog’s breed isn’t listed.

  •          Bernese Mountain Dog
  •          Bull Mastiff
  •          Cane Corso
  •          Great Dane
  •          The Great Pyrenees
  •         Irish Wolfhound
  •          Newfoundland
  •          St. Bernard
  •         Scottish Deerhound

Dog Breeds That May go into Heat Sooner

There are also dog breeds that may not only go into the dog heat cycle sooner but more often, depending on the dog’s age. Let’s look at some of those breeds. You can ask your veterinarian if your dog’s breed isn’t listed.

  •          Basenji
  •          Beagle
  •          Bichon Frise
  •          Boston Terrier
  •          Corgi
  •          King Charles Spaniel
  •          Chiaawa
  •          Dachsund
  •          Yorkshare Terrier

How Long is a Dog in Heat for?

The first two stages of a dog’s heat cycle usually last between two to four weeks, which will vary once her cycle officially starts. The diestrus stage will be affected depending on whether or not a dog has become pregnant.

Will a Dog Have Heat Cycles for her Entire Life?

A female dog will experience heat cycles throughout her life. Unlike humans, a dog does not experience menopause. However, the time between each heat cycle or heat period will increase as she ages. There is also a chance she may be no longer fertile.

How Do I Know My Dog is in Heat?

Part of being good pet parents is understanding your dog’s behavior and signs in your dog. And if you have an unaltered female, you definitely want to ensure you know the signs of your dog’s heat cycle.

Let’s look at the most common signs that your dog is entering a heat cycle.

Vaginal Bleeding or Discharge in Your Dog

When a female dog enters her heat cycle, you may notice some light-colored discharge or bloody discharge coming from her vagina. This is normal. As she enters the estrus stage of her heat cycle, this bloody discharge will grow heavier, and then the blood spot will lighten.

More Frequent Urination in Your Dog

If you find your female dog suddenly urinating in the house or more often, understand that is a very common sign of her entering her heat cycle. Frequent urination is often the first sign.

Swollen Vulva and Genital Licking in Your Dog

A female dog’s vulva will begin to swell, and you may see her paying extra attention to her genital area by licking it.

Increased Fondness for a Male Dog

Once a female is in heat, she will be more receptive to mating. She exposes and raises her rear end toward unneutered male dogs. By having this tail position, she presents to the male and lets him know she is ready to mate. She is very much ready to accept male company.

Nervous or Aggressive Behavior in Your Dog

You may notice that your female dog seems more nervous or even aggressive during her heat cycle. She is secreting those mating hormones, and a change in attitude is completely normal.

How Can I Prevent an Unwanted Pregnancy in My Dog?

If you aren’t ready to welcome a litter of puppies, there are things you can do during your dog’s heat cycle to monitor her and prevent an unwanted pregnancy.

You always want to be leash walking during your dog’s cycle. Even if she has excellent leash training and obedience skills, she needs to be on a leash as her hormones will overrule any good manners she has. It’s really best to keep her away from other dogs.

If your female dog is outside, even on a tie-out in the backyard, she will need to be supervised at all times if you want to avoid her becoming pregnant. A female dog in heat is a big temptation to any passing by or stray male dog, and attracting male dogs will only encourage them.

Your dog will also need supervision when inside if she is in her heat cycle. This is true, especially if you value your furniture and carpets. Because dogs in heat spots can leave behind blood and stain certain surfaces of your home.

As silly as it may sound and look, using diapers during your dog’s heat cycles is a great way to prevent messes. Not only will she be spotting blood, but her increase in urination can also cause messes. Diapers will also catch any vaginal discharge.

Diapers are a great way to contain these messes and keep your home clean. They do make doggie diapers, so you won’t have to use those Huggies or Pampers.

Diapers also have disposable liners and are made special for a dog’s body with a spot to accompany her tail. Dog diapers also come in a variety of sizes. Having dog diapers around can help you prepare for the next heat cycle and prevent unwanted litter.

What if I Do Want Puppies?

While it may be natural, this can be more tricky than you think. An unspayed female dog is most receptive to mating during the eleventh day of the menstrual cycle, but ovulation can occur early or later in the heat cycle.

How Can I Arrange for a Successful Mating Session for My Dog?

If you are a breeder or you want to welcome a litter of adorable puppies, there are some things you can do to help the mating session be successful.

Interestingly enough, male dogs have a higher stress rate than females during mating. Therefore, unless your dogs live together, you may have more success if you encourage the dogs to mate at the male dog’s home.

The correct timing for a successful mate is critical. If you are serious about it, you can have your female dog tested at the veterinarian’s office to see the best days for mating.

Ideally, you want to focus on the oestrus cycle’s tenth and fourteenth days. But some dogs will ovulate as early as the third day or as late as the eighteenth day.

Pregnancy isn’t always guaranteed with the first mating session, which is why it’s important to arrange for a second date, if you will. You will want to space these get-togethers apart between 24 and 48 hours in an ideal environment.

You may hear the term “tied” when discussing mating between dogs. Though it sounds simple, the process is a little more complicated.

In a male dog, the coitus or bulbis glandis, part of his penis enlarges and is held by the female dog’s vagina muscles. This prevents the penis from being withdrawn, and this “tie” is considered a feature of productive mating.

However, a successful mating session can occur without the dogs being tied as long as it’s breeding season.

Signs of Pregnancy

If you are confident that your female dog may be pregnant, it’s important to recognize the signs, as we don’t have the luxury of an at-home pregnancy test for dogs. Always see your veterinarian, as these can also be signs of other health issues. Once your dog has one or two litters, it is a good idea to consider spay surgery. Letting a dog get pregnant too much can present dangerous situations, like mammary cancer.

  •          Weight gain
  •          Increase in appetite or a decreased appetite
  •          Swollen belly
  •          Increase in nipple size
  •          Sleeping more
  •          More affectionate
  •          Nesting behavior
  • Increased irritability
  • Vaginal discharge

However, the only tried and true way of confirming your dog’s pregnancy is by visiting the veterinarian, where they will perform some diagnostic tests.

One surefire way to confirm pregnancy is through ultrasound. Done between 25 to 35 days gestation, the ultrasound will confirm the presence of fetal heartbeats. An ultrasound can also give you a decent estimate of how many puppies are present.

If you are fairly certain of when your dog became pregnant, your veterinarian can palpate her belly around the 30-day mark. The puppies will feel like small golf balls or grapes, but what you feel are actually the sacks surrounding each puppy.

Another extremely effective way to confirm pregnancy is by doing an x-ray. Best done after 55 days of gestation, an x-ray will give you an accurate number of puppies and will provide you with a good idea of when you can expect your dog to go into labor.

Your veterinarian can also perform a blood test around 25-30 days into the pregnancy to see if she is producing the pregnancy hormone relaxin and if she has shed her uterine lining. Visiting your veterinarian is also a good way to prevent a uterine infection.


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