The Reproductive Dog Breeding Cycle

Having your finger on the pulse of the reproductive dog breeding cycle of your bitches is the single most important factor to getting the litters you want.

reproductive dog breeding cycle
Take control of your breeding.

And it’s not easy!  All cycling bitches experience a defined heat period within which there is a small window of opportunity for fertilization to occur.  But there is a lot of variation in the frequency and length of the reproductive cycle between different breeds and different bitches.

The Reproductive Dog Breeding Cycle Can Be Tricky!

  • It can vary from one cycle (or heat) every 18 months (this is typical of some of the giant breeds) to one every 4 months.  The average bitch will cycle approximately every 6 months and an individual bitch will tend to conform to her own unique repeating pattern throughout her fertile years.
  • The “average” bitch bleeds for 9 days (proestrus), then will stand for mating for 9 days (estrus).  But one in three bitches don’t fit the average!  So using the old rule of thumb to mate on days 9 and 11 (or 10 and 12 – depends who you talk to) from day one of bleeding will fail a lot of the time.
  • To make matters even more difficult for the would-be dog breeder, the bleeding that marks the start of her heat is unnoticeable in half the bitches out there.

Small wonder failure to achieve pregnancy is a number one frustration for dog breeders.

Mating problems in dogs are the other big frustration

Imagine:  You’ve got your ducks in a row in your timing in the reproductive dog breeding cycle, but they won’t “do it”.

It’s a little known fact that there are lots of dogs out there who are rather inconveniently choosy about who they’ll tango with.  Both dogs and bitches may refuse to mate if they don’t find your choice sexually attractive, even if the dogs involved are normally the best of friends.

So what can you do to make the reproductive dog breeding cycle work no matter what life throws at you?

Mating at the right time in the Reproductive Dog Breeding Cycle

Even where both the bitch and the dog are healthy, and mating occurs at exactly the right time, about one time in seven you won’t end up with a litter.  And once the bitch is six years old her chance of conceiving drops by a third; once she is 7 years old, it drops by a half.

Breeders' Canine Artificial Insemination Kit
Canine Artificial Insemination Kit

That is normal and a fact of life, so don’t assume something is wrong if you miss a pregnancy now and then.

Aside from that, accurate timing of mating is the single most important factor for breeders in optimizing both the number and size of the litters that they are able to breed.  It is also the area where breeders most commonly run into problems.

Fresh dog sperm is capable of fertilizing an egg for 5 to 6 days. A few days before estrus ends, the follicles on the ovaries of the bitch will ripen and burst, releasing the eggs.  However, the eggs are not mature enough for fertilization until 2 to 3 days after ovulation.  And once mature they remain viable for a further 2 to 3 days.

The biggest litter size, therefore, will be achieved when a bitch is bred two days after ovulation, when both semen and eggs will be at their peak viability.  However, a successful pregnancy can still result if the bitch is bred any time between the 2 days prior to ovulation to the 4 days after ovulation.

So the challenge for you as a breeder is in pinpointing when your bitch has ovulated.  There are several methods available and they vary in their simplicity, accuracy and expense.

Pinpointing Ovulation

Bitch in heat
Vulva in proestrus

Breeders have access to a range of means of pinpointing ovulation:

Visible signs of estrus

  • Vaginal bleeding that usually diminishes as ovulation approaches
  • Swelling of the vulva
  • Bitch’s positive response to the male
    • Standing still to allow the dog to mate her
    • Flagging of the tail (it moves to the side)
    • Raising her back end toward the dog.
    • Flirting with the dog (gamboling playfully around him in a teasing manner).

However, some bitches will respond positively to the dog throughout proestrus, and some will never respond at all, even at ovulation!

For the bitch that does respond, the breeder can ensure that fertilization had occurred by mating her every two to three days during her estrus period.

For the bitch that doesn’t, the breeder can learn how to do their own Artificial Insemination (AI) and inseminate her with semen collected from their own dog at the same 2 to 3 day intervals.

However, if you need to use someone else’s dog, either for a natural mating or AI (especially if using short-lived frozen sperm), then pinpointing ovulation accurately may be necessary.

Use of Glucose Sticks or “Canine Ovulation Pads”

Canine “Ovulation Pads” are just cheap glucose detection sticks (used for urine to diagnose diabetes) with a hefty price rise.  Glucose detecting reagent strips are sometimes used at home by the breeder to avoid expensive veterinary costs associated with more invasive techniques discussed below.

Theoretically glucose may be first detected in vaginal fluid between 3 days before and 3 days after ovulation.  As we have seen, eggs are not ripe for fertilization until 2 to 3 days after ovulation and remain viable for a further 2 to 3 days once mature.  Thus, if mating or Artificial Insemination takes place on the first day that the glucose is detected in the vaginal fluid, then repeated 3 days later, it is possible to cover the fertile period and result in success.

However, this technique is not as accurate as vaginal smears or blood tests.  And I have found that it can be difficult to get enough fluid to adequately moisten the strip and achieve a meaningful result.  The other problem with glucose sticks is the high chance of contamination with urine while performing the test which can result in a false reading.

Some breeders reckon they have worked for them, but I believe that is more about luck than anything else.

Use of Breeding Records

Keep a comprehensive record of your bitch during her heat period (even if you don’t intend to mate her).  Very often she will exhibit the same characteristics time and again from one heat season to another.  Take note of:

  • Behavior – Behavior may be your first clue that a heat is approaching. Bitches coming into heat or on heat may mount or be mounted by other dogs, male and female. They may lick each other’s vulvas, or become unusually playful and flirtatious.
  • Vaginal secretions – Are they bloody and copious and do they taper off to a more serous discharge towards the end of her heat? Perhaps she hardly secretes at all?
  • Duration – Does she exhibit the “typical” timing or an extended or very short heat?
  • Whelping date – Whelping occurs 62 to 64 days after ovulation. If you go back on your records you will then know what signs to look for when that bitch ovulates next time.

Vaginal Smear

canine fertility test
DIY Vaginal Cytology

Your veterinarian may offer you a cheaper option to blood tests that is less distressing to the bitch.  This is the use of vaginal smears.  The veterinarian (or trained owner) stains, and studies the smear microscopically to check the proportion of cornified epithelial cells present in vaginal secretions which indicates if the bitch is in estrus or not.   The shape of the cells and types present give a good picture of what stage of her cycle the bitch is at. Vaginal Cytology should be carried out at least 3 times, starting day 5 after bleeding starts and thereafter every 2 days until the percentage of cornified cells is >60%.

Vaginal smears are useful indicators of when a progesterone test should be taken, avoiding the cost and discomfort of multiple blood tests.

I use vaginal smears as a canine fertility test exclusively now (learn how to do it at home yourself here.).  If a bitch’s smear shows she is in estrus, I mate her.  I take a new smear every 2 days thereafter and repeat mating until the smear shows estrus is over.

Blood Progesterone

Progesterone is a reproductive hormone that begins to increase in the bloodstream just prior to ovulation.  For most bitches when progesterone rises to 2.0 nanograms (one billionth of a gram) ovulation is imminent, and when levels reach 5.0 to 10.0 nanograms, the bitch is ovulating.

Progesterone levels are a very accurate means of pinpointing ovulation. However, the tests are expensive and distressing for the bitch, as blood will need to be drawn several times every 3 days until ovulation is detected. If frozen semen is being used timing is more critical and even more frequent sampling is needed.  Another drawback is that the blood needs to be assessed by a laboratory, so if you live in a remote area it may take up to 3 days to get your result!

Veterinarians defend the expense and distress to the bitch of this method with the lure of maximizing litter size and breeder revenue, and in some cases this may be quite justified.  A handy way to safely narrow down the number of tests needed is by using progesterone assays in conjunction with vaginal cytology.

Blood Luetinizing Hormone (LH)

As it is the hormone that triggers it, Luetinizing Hormone normally peaks just prior to ovulation.  The blood test for blood has similar drawbacks to the blood test for progesterone, and an added disadvantage:  the LH surge is very fleeting, so actually catching it can mean testing your bitch once or even twice a day – which can get rather expensive.

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