Progesterone Testing & Assisted Breeding in Dogs

Progesterone testing is a common procedure in dogs that is used to assess reproductive health and diagnose certain conditions. Progesterone is a hormone produced by the ovaries and plays an important role in the menstrual cycle and pregnancy.

Progesterone testing is typically performed by collecting a blood sample from the dog and sending it to a laboratory for analysis. The results of the test can help veterinarians determine if a dog is pregnant, predict when she will give birth, and diagnose any hormonal imbalances that may be affecting her reproductive health.

Progesterone testing may be recommended for dogs experiencing fertility problems, irregular estrous cycles, or abnormal vaginal bleeding. It can also be used to monitor the progression of pregnancy and determine the best time for inducing labor.

When it comes to reproduction “timing” is everything to make sure that the sperm and eggs meet on time! We use lots of different indicators and tools besides just animal behavior to determine when is the “best” time. The measurement and charting of hormones is fast becoming one of our most reliable tools. There are multiple hormones that help to regulate the estrus (heat) cycle and pregnancy in dogs. These include:

• Estrogen: Stimulates the ovaries to produce eggs.

• Luteinizing Hormone (LH): Stimulates the ovaries to release the eggs.

• Progesterone: Maintains a pregnancy.

We need to fully understanding how the hormone levels change so they can help us in determining the best time to breed naturally or with artificial insemination or surgical implantation and also when to anticipate whelping or to do an elective C-section.
It seems that usually most mammals ovulate when the estrogen level in the blood is still increasing. Dogs, however, ovulate when the estrogen level is already declining and the progesterone level is increasing. Estrogen levels can give us a general idea of when a dog will come into “standing” heat, but are not sufficient to determine when breeding should actually take place for optimal conception rates.
Vaginal cytology can also provide some general information. Vaginal cytology is performed on female dogs during their estrus cycle to help determine the optimum time to breed and enhance the success of pregnancy. The types of cells present in the vagina vary depending on the stage of estrus. A swab is taken of the cells lining the vagina and analyzed under a microscope. Usually more than one swab is required to determine the optimum time to breed.
Progesterone levels and luteinizing hormone (LH) levels are the best indicators of when ovulation will take place and when is the best time to breed. They are also useful in determining whelping dates, allowing an owner to reserve the appropriate days on the calendar and even to schedule a C-section (Cesarean) weeks in advance.

The progesterone test is not species specific so the test can be run in in clinic, in  human labs or veterinary labs. Results should be available in less than 24 hours to keep things on time. Different labs have different tests and report result in different measurement units. To switch between the American units and the International units multiply by 3.18. 

• The normal progesterone ranges are as follows:

• Anestrus (not in heat) is less than 3 nmol/L

• Late Proestrus (early heat) is 6-8 nmol/L

• LH surge is 8-12 nmol/L

• Ovulation is 12-24 nmol/L

• Past Ovulation is greater than 24 nmol/L

The progesterone test can be done every 2-3 days starting about 3-5 days into the heat. Timing of the test can be more certain if the lengths of the dog’s previous heat cycles are known. The beginning progesterone levels are typically less than 1.0 ng/ml until the day before the LH surge. The day of the LH spike, serum progesterone concentrations are 2-3 ng/ml; the day following the LH surge, the serum progesterone concentration is 3-4 ng/ml. Ovulation occurs at a progesterone level of 5 ng/ml.

Timing of breeding

The aim is to identify when the progesterone level reaches 2.5 ng/ml so the mating schedule can be set up, or the veterinarian and owner of the male dog can be notified that they should be prepared to collect and ship a semen sample. Depending upon the type of semen used, optimal times for natural or artificial insemination are:

• Natural breeding should occur 3 days after the 2.5 ng/ml mark. Sperm in fresh semen survive 5-7 days after insemination.

• Artificial insemination using fresh chilled semen should be used for a 1-time breeding. Insemination should take place 4 days after the progesterone reaches the 2.5 ng/ml mark or 48 hours after the 5 ng/ml mark. Sperm in chilled semen survive 48-72 hours after insemination. With artificial insemination, the semen should be deposited into the cervix to increase the chance of it being drawn into the uterus.

• Artificial insemination using frozen semen should be performed 5 days following the 2.5 ng/ml mark or 72 hours after the 5 ng/ml mark. Sperm in frozen semen survives less than 24 hours after insemination. Frozen semen is ideally deposited directly into the uterus through surgery to increase the chance of pregnancy.

We also advise additional tests be performed on your breeding female prior to her estrus cycle. Blood work including a thyroid analysis will rule out any potential breeding problems that may be addressed prior to the breeding period.

Semen from a natural “tie” or side by side AI may live on average up to 7 days, while fresh chilled semen may only live for 48 hrs, and frozen semen for only 12-24 hrs. One must be very accurate when timing the procedure to allow for egg and sperm to meet while still alive.

Progesterone Results Summary:

• All results are in ng/ml 1.0 or less: Your dog is very early, too early to predict the best time to breed. Retest in 2-3 days. Going over 3 days may mean missing the best time to breed your dog.

• 1.0 to 2.0: Check every other day. Frozen semen can be ordered at any time as we can store it here until your bitch is ready.

• 2.0 to 5.0: Test every day. Your dog could be ready almost any day.

• 10. We usually start natural breeding's the day the progesterone goes over 10. For fresh chilled and frozen semen, we usually want the progesterone between 15 and 22. Progesterone levels can sometime double in 24 hours so daily testing is imperative.

• 15-22: Your bitch is ready to breed. This is the best time for Transcervical and Surgical insemination.

• 22-30: Your bitch is at the end of her fertile time. We recommend a Transcervical or surgical insemination at this time.

• 30-35: Some dogs still conceive with progesterone’s in this level, especially those who are still 3-6 days since they ovulated, or when the progesterone went over 6. Transcervical or Surgical insemination is best, because the cervix will be starting to close.

• 35 and above: The best time to breed your dog has already passed.

Assisted Breeding Options:

1. Transcervical Insemination

(No Anesthesia, no surgery)

This economical, non-anesthetic procedure has been shown to be more successful than

surgical implants. An endoscope is placed in a special shunt and inserted vaginally, the

bitch's cervix is then visualized. A special sterile catheter is inserted through the scope,

past the cervix and into the uterus. This is the same place the semen is inserted in a

surgical implant. This procedure can be done multiple times in one season and can be

done with frozen semen, fresh chilled semen, or fresh semen.

2. Surgical Inseminations

(General Anesthesia and Surgery Involved)

the gold standard of inseminations, this procedure is still commonly practiced especially

for dogs that have had problems conceiving or with frozen semen. Our surgical implants

include pre-anesthetic lab work ad pain medication for your bitch, along with state-of the-art anesthesia and monitoring.

3. Artificial insemination

(Modified with a special catheter)

At Chino Hills this includes a semen evaluation and a special catheter that places the

semen at the opening of the cervix and the inflatable tip mimics the tie of the male dog,

forcing semen in through the cervix.