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Dog Reproduction (The Heat Cycle)
Signs of Heat


The first sign of a female (dam) coming "into season" is often swelling of the vulva. This swelling can occur a week before bleeding, or the day before. Other signs of heat are behavioral changes; your dam may start to hump other dams, or pups or even your leg. She may also begin to lick herself a lot.


If you own more than one dam, they will usually cycle together; one dam in heat will bring other dams into heat. 

A female should NEVER be bred on her first heat (she has immature eggs) and preferably not her second either. The rule of thumb that works best is to breed on the third season, or at one and a half to two years of age, and after all health tests have been passed.

Small vulva—dam not in heat


Small vulva—dam not in heat


A female dog in full standing heat swollen up.

A female dog in full-standing heat swollen up


A dam in heat and almost ready to be bred. You really need to stand your girl up, and look at the vulva. It will tip upwards and change position slightly to make it easier for the male to penetrate, also if you insert a gloved finger it will squeeze your finger inward. When a female ovulates, she will try to mount the male. She will have a very STRONG, distinct smell that dogs from MILES around can smell. Her discharge will have changed from bright red to a more yellow color.

Dam in heat. The vulva is swollen, sticking out from the body and three times the normal size.

Dam in heat. The vulva is swollen, sticking out from the body and three times the normal size.

Dam in heat. The vulva is swollen, sticking out from the body and three times the normal size.

Dam in heat. The vulva is swollen, sticking out from the body and three times the normal size.

Female dog in heat

Female dog in heat dripping blood and vaginal fluid.


Other signs of being "ready to breed," are her willingness to stand for the male and she will hold her tail off to the side, called "flagging." She will often back her butt up to your leg as well..

A vet has ways to tell when she is fertile, but you still have to watch for the swelling and bleeding.


You will notice after her first heat that her teats will be more noticeable.


Nine-month-old female before heat—no boobies


After heat—tiny, pink, more noticeable boobies


So your dog has come into heat

It is most common for the dam to come into heat at six months of age and then every six months thereafter. Some dams come in at four months and some at twelve months for their first heat, while some are every six months and some every five to 11 months. All dams vary, so you should keep track of what your dam is doing and when.

Most breeders breed their dams on the third heat or after one and a half or two years of age when proper genetic testing is complete and the vet gives approval that dam is an adult and ready.

So, when is she fertile?

If you have the male with you he will tell you. Normally it is about 12 days after the bleeding starts, when the bleeding has slowed and thinned to pink. The male will know, he will regularly check, lick, analyze in his built-in lab   ;-)

BUT, if you are taking your dam to the sire the use of a vet is needed.

On day one call your vet for instruction. He will likely have you come in for a smear on days five, seven and nine, and will do a blood progesterone test on days nine to 11. Then you will know exactly when the peak is. This is the type of testing the vet does if they are doing artificial insemination or a surgical implant.

This blood test measures in nonamoles and nanograms. Each measurement is different. It tests her progesterone levels, and lets you know when she drops eggs and when the eggs will ripen.

Recently we bred our girl; the following were her blood test measurements(nanomoles per liter):

7 nanomoles = 2 nanograms

2.5 on day seven, 4.2 on day nine

7.0 on day 11, 16.1 on day 13 (ovulation)

A smear, done earlier in the cycle, will test for cornification. It is not as accurate, but when she is fully cornified, she is ready to breed.

Puppies are born 63 days from ovulation. (Not 63 days from breeding, as the male can breed her several days before, and after ovulation)

Fresh sperm can live five days (maybe seven days at most). Chilled sperm last 12 (max 24) hours after insertion. Frozen sperm last one (two) hours after inserted. 

An egg lives five days. But on day one the egg is immature and cannot be penetrated. On day three the egg will be ripe, and this is the best day to inseminate. On day four, eggs are still ripe, and on day five the eggs are dying.


See Breeding Tie for more breeding info


Belly Bands for Male Dogs:

Belly Bands for Male Dogs

Belly bands are a GREAT training tool for male dogs to keep them from marking (lifting their leg on your furniture). Put them on while they are in the house, and take them off when outside. Also if a dam is in heat, it helps to stop the marking.





Belly Bands for Male Dogs

Belly Bands for Male Dogs

Generally the dog comes into heat, and the experienced breeder notices right away, while the newbie may not notice till day four.

Normally they are breedable on approximately day 12 to day 18, but they can remain in heat till day 21.

Each dog is different, and heat averages two to three weeks. They start to bleed, and then by day 12 it goes pink, and by day 16 they stop bleeding. Unfortunately many people think when they stop bleeding, they are out of heat, but in a dog, it means they ovulated. So...many unplanned breedings happen.

Note: you cannot spay a female when she is in heat, or just after, as everything swells up and there is too much blood. Six weeks after is usually fine. Always ask your vet.


Courtesy of MistyTrails Havanese


So You Want to Breed

Pros and Cons of Inbreeding

Stages of Puppy Development

Whelping Puppies: Breeding age

Reproduction: (The Heat Cycle): Signs of Heat

Breeding Tie

Dog Pregnancy Calendar

Pregnancy Guide Prenatal Care

Pregnant Dams

Pregnant Dam X-Ray Pictures

Full-Term Mucus Plug


Whelping Kit

First and Second Stage of Labor

Third Stage of Labor

Sometimes Things do not go as Planned

Dam Almost Dies on Day 6

Whelping Unfortunate Troubles

Whelping: A Green Mess

Water (Walrus) Puppies


C-Section Due to Large Dead Puppy

Emergency Cesarean Section Saves Lives

Whelping Puppies: C-section Pictures

Dam Day 62


Birth to 3 weeks

Puppy Nipple Guarding

Pups 3 Weeks: Time to start potty training

Pups Week 4

Pups Week 5

Pups Week 6

Pups 6 to 7.5 Weeks

Pups 8 Weeks

Pups 8 to 12 Weeks

Whelping Large Breed Dogs

Mastitis in Dogs

Mastitis In Dogs: A Toy Breed Case

Why are Toy Breeds are Harder to Train?

Crate Training

Showing, Genetics and Breeding

Trying to Save a Fading Dachshund Puppy

Whelping Stories: Three Puppies Born

Whelping: All puppies do not always survive

Whelping Puppies: A Midwoof Call

Whelping a Full Term Preemie

Whelping Small for Gestational Age Puppy

C-Section Due to Uterine Inertia

Eclampsia is Often Fatal

Hypocalcemia (low calcium)

SubQ hydrating a Puppy

Whelping a Singleton

Premature Litter

A Premature Puppy

Another Premature Puppy

Pregnant Dam Absorbing Fetus

CPR Needed to Save One Puppy

Whelping Puppies Congenital Defects

Puppy with Umbilical Cord Attached to Foot

Puppy Born with Intestines on the Outside

Gone Wrong, Vet Makes it Worse

Dam Loses Litter and Starts to Absorb Puppies

Whelping Puppies: Unexpected Early Delivery

Dam whelps 5 days early due to dead pups

Lost 1 Puppy, Saved 3

An Abscess on a Puppy

Dewclaw Removal Done Wrong

Whelping: Heat Pad Caution

Whelping a Large Litter

Whelping and Working

Whelping a Messy Litter of Pups

Whelping Puppies Picture Pages

How to Find a Good Breeder

Pros and Cons of Inbreeding

Hernias in Dogs

Cleft Palate Puppies

Saving Baby E, a Cleft Palate Puppy

Saving a Puppy: Tube Feeding: Cleft Palate


Although this section is based on a whelping of an English Mastiff, it also contains good general whelping information on large-breed dogs. You can find more whelping information in the links above. The links below tell the story of Sassy, an English Mastiff. Sassy has a wonderful temperament. She loves humans and adores children. An all-around mild mannered, wonderful Mastiff, Sassy, however, is not the best mother toward her puppies. She is not rejecting them; she will nurse them when a human places them on her to feed, however she will not clean the pups or pay any attention to them. It is as if they are not her puppies. This litter is getting mom’s milk with major human interaction, manually giving each and every pup what they need. In return, the pups will be super socialized and will make remarkable pets, however the work involved is astounding. It takes one dedicated breeder to keep this situation healthy. Thankfully this litter has just that. Read the links below to get the full story. The pages within include a wealth of information that everyone can appreciate and benefit from.

C-Section in a Large Breed Dog

Newborn Puppies... What you need

Whelping Mastiff Puppies One to Three Days Old

Things do not always go as planned (imperforate anus)

Orphaned Litter (not the plan)

10 Days Old Plus +

3 Week Old Puppies

Puppies 3 Weeks - time to start potty training

Puppies 4 weeks old

Puppies 5 weeks old

Puppies 6 weeks old

Puppies 7 weeks old

Socializing the Puppies

Mastitis in Dogs

Whelping Large Breed Dogs Main

Whelping, a new found respect


Whelping: Close-to-Textbook Case

Puppies' Progress Chart (.xls spreadsheet)

Cuban Mysti Puppies: Full Term Mucus Plug - 1

Cuban Mysti Puppies: Labor Story 2

Cuban Mysti Puppies: Labor Story 3

Cuban Mysti Puppies: One-Day-Old Pups 4

Easy Delivery a Day or Two Overdue


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