Reproductive Stages in Dogs
Calcium is critical to your dog but be very cautious during this phase

The reproductive stages in dogs, contrary to some misconception, can vary a lot depending on the breed and size of your dog.

In small breeds, puberty can happen as early as six months of age, while larger breeds may not reach their full puberty to as late as two years.

Reproduction in your dog is a very complex event, and for the actual pregnancy to occur, all of the circumstances will have to be just right.

Although it is a very natural cycle, it is also very complicated.


Both female and male puppies are born with all of their reproductive organs.

However, like many of their other organs, they are not fully developed.

With female puppies, the ovaries do not become fully developed until they mature, and this can vary depending on their breed.

In male puppies, the testicles are not yet fully descended within their scrotal sac until they mature.

Reproductive Anatomy

To help in fully understanding the reproductive stages in dogs, it is very helpful for owners to have an understanding of the anatomy of both female and the male dogs.

The female anatomy is much more complicated than a male dog, and is usually the best place to start in this very complex yet miraculous process of life in your pet.

Female Anatomy

The reproductive stages in dogs are quite unique, but the reproductive system itself is very similar to humans.

With female dogs, the reproductive system is made up by five components: the ovaries, oviducts, cervix, uterus, and the vagina.

The ovaries, much like a human, are by far the most complex of these components as it has several functions.

It is the site of the production of unfertilized eggs as well as several of the organs that ignite the heat cycles as well as maintaining the actual pregnancy.

The eggs from the ovaries of your dog will than pass into their oviducts, which are small tubular structures and are the site of the fertilization by the male sperm.

From here, the eggs travel into the uterus where the embryo matures and is supported by the walls of the placenta which completely surrounds this new life.

Perhaps the most important part of the reproductive stages in dogs is the heat cycle of the female.

Heat cycles are both caused and controlled by hormones that are produced and released by the ovaries.

Sleeping puppyReproductive stages in dogs are nothing short of a miracle

The ovaries are very similar to paired structures that will become much more active when your dog finally passes through the actual puberty stage, and it becomes first heat cycle.

This is where the size and the breed of the dog really come into play.

In toy and small breeds, this first cycle can occur as early as five to six months of age, while very large breeds may not occur until as late as eighteen months.

Once they finally occur, they will than settle in and repeat between six and nine months for the rest of your dog’s life.

However, there are some caveats to this; both very young and very old dogs may have what is referred to as silent heats.

This is a situation where your dog will show absolutely no signs of being in heat. There is also one major difference with dogs; they do not undergo any form of menopause.

Male Anatomy

Reproductive stages in dogs obviously could not occur with male dogs, but they have an entirely different anatomy in several ways.

In males, there is no form of seasonal period and they can be aroused anytime by a female in heat.

Their anatomy is made up of the testicles, ductus, prostate gland, and their penis.

Once the sperm is ejected, it is transported to the prostate gland where additional fluids are added as nourishment.


Reproductive stages in dogs are divided into four stages: proestrus, estrus, diestrus, and anestrus. The first stage, proestrus, is referred to as the preparatory stage or period.

This period of time will be somewhere between five and nine days in your dog.

One of the signs that you can watch for that the first stage has arrived, is the swelling of the females vagina.

Once this occurs, it is very quickly followed by a bloody discharge, and male dogs are immediately attracted to the female.

However, she will show absolutely no interest at this time.

During this process, the walls of the female’s reproductive tract thicken, and your veterinarian can actually gather cells from the female.

They can then determine exactly where they are in the actual cycle period.

The second of the reproductive stages in dogs is called the estrus, and this is the active breeding stage.

This stage will generally last between five and ten days. At this stage, the females bleeding is either completely stopped or will be very minor.

It is in this stage that the eggs are released from the ovaries and travel into the oviduct.

This stage will attract all males, and they will attempt to mate if given the opportunity. It is this stage where the female also becomes attracted, and once mating does occur, a tie takes place.

A tie occurs where the male and the female are held together physically, allowing for ejaculation to occur which than allows the eggs to enter the uterus.

If everything in both dogs is physical correct without any type of complication, fertilization occurs.

The third of the reproductive stages in dogs is the diestrus stage and it will extend form the time frame where the female is no longer attracted to the male to the end of the pregnancy.

The average span of pregnancy in most dogs is 62 days, but there is also a possible glitch to this stage.

If for some reason the pregnancy did not take, diestrus could last as long as 80 days.

However, if everything worked properly, it is this stage that the embryos and their placentas will attach themselves to the walls of the uterus.

Once attached, they can then start to receive both oxygen as well as the much needed nutrients.

The final stage is called the anestrus stage, which is the period between heat cycles. In this stage, there is no interest by either the male or the female for any type of sexual activity.

The reproductive stages in dogs will only be successful if your dog is fed a balanced diet for the duration of the pregnancy.

Overfeeding as well as underfeeding could have catastrophic effects on both the mother as well as the litter.

There is a general tendency by owners to overfeed during pregnancy and then underfeed at the most crucial point in this entire process, which is the nursing period.

During this critical period, your dog will need plenty of their most important nutrients; water.

Supplements for dogs can be extremely beneficial at several points in your dog’s life, but this is a stage where you need to be extremely careful.

Do not supplement anything unless it is recommended by your veterinarian.


The worst thing you could do for your dog during this period is to give them calcium supplements, unless directed by a professional.

Calcium is crucial to dogs in several ways.

However over supplementation at this point in their life can easily cause difficult deliveries, soft tissue calcium deposits, as well as joint abnormalities.

Pet Medications to Assist the Reproductive Stages in Dogs

Dog Vitamin Store

Other Related Topics


Is the inflammation of your dog’s penis as well as their prepuce.

Maternal Immunity

It is very helpful to understand that there are two types of immunity that is passed from the mother to the litter.


Is a bacterial infection that is so mysterious that it is not unusual for your dog to have this infection but show absolutely no symptoms at all.

Orphan Puppies

The most critical factors will be a very detailed and regimented schedule and adequate warmth for the puppies.