Progesterone and LH Testing in Dogs – Ovulation Testing and Fertility Checks

Progesterone and LH Testing in Dogs – Ovulation Testing and Fertility Checks

Even the most experienced dog breeders can have problems with deciding when to breed their bitch. Some bitches ovulate early, while others undergo split heats or silent heats. Because of this, many breeders will undertake progesterone and LH testing in dogs to determine the best times to mate their dogs.

Dog progesterone and LH testing is done by taking a sample of whole blood from your dog. After processing the sample, a vet can help you to determine when your dog will ovulate and the best times to breed your dog.

What is Progesterone and LH Testing in Dogs?

Progesterone testing pinpoints when your bitch will ovulate and the best days to mate her. As such, this test helps to improve fertility and prolificacy when breeding your bitch, since bad timing with breedings is a major cause of infertility. Progesterone tests can also help to predict parturition, diagnose delayed puberty, identify silent oestrus, and work around split heat cycles. In summary, quantitative progesterone tests involve taking blood samples from your bitch. The results are usually given as a numeric value such as ng/mL.

LH testing often occurs alongside progesterone testing to pinpoint exactly when a bitch ovulates. This allows breeders to decide when is best to breed their bitch. However, LH testing is not commonly done by itself, as the LH surge before ovulation ends quickly. As a result, progesterone levels are also checked to confirm that ovulation is imminent – progesterone levels rise alongside LH. LH testing is also used to identify spayed females and to diagnose some ovarian tumors. Similar to the progesterone test, the LH test is done by drawing a blood sample for testing.

Hormonal Changes During Dog Ovulation

The main hormones involved in ovulation are estrogen, luteinizing hormone (LH), and progesterone (P4). Each hormone has a different role in your bitch’s ovulation. These hormones also work together to ensure that the cycle is complete. So which hormones should you test for? And which hormones tell us when ovulation is about to happen? Read on with us to find out more.

Estrogen

Your bitch’s proestrus begins with estrogen (estrone, estradiol, estriol) production. Estrogens are responsible for the sexual development of the bitch. These hormones kickstart a wide range of physical changes during her heat cycle. With increased estrogens, your dog will show her first signs of heat, including vulval swelling and pink-white discharge. These changes persist for about nine days.

One specific type of estrogen, estradiol, is made in the follicles of the ovaries and increases in concentration up until ovulation occurs. Estradiol works by stimulating the growth and thickening of the womb lining which prepares the bitch for pregnancy. Once estradiol reaches its peak concentration, the luteinizing hormone surge begins and triggers ovulation.

Luteinizing Hormone

Luteinizing hormone (LH) is a hormone that works alongside follicle-stimulating hormone (FSH) and estradiol (E2) to trigger ovulation. Once the follicles in the ovaries are mature, 17α-hydroxyprogesterone (a relative of progesterone), stops further estrogen production and instead stimulates the surge of LH to prepare for the release of eggs. This LH surge lasts for 24 to 48 hours. Testing for LH thus reveals that ovulation is about to occur. However, this LH surge is not always caught on time, so most vets will recommend testing for progesterone as well.

Progesterone

Alongside the LH surge comes an increase in progesterone production. Progesterone is important because it prepares your bitch for pregnancy. If the eggs undergo fertilization, progesterone stimulates the growth of blood vessels that supply the endometrium of the womb. It then prepares the tissue lining of your bitch’s uterus to allow for egg implantation. So, the LH peak typically occurs once progesterone levels reach 2 to 3 ng/mL, at which point ovulation should occur two to three days later. Ovulation begins once your dog’s blood progesterone levels reach 5 to 8ng/mL, so a vet can pinpoint ovulation by testing for this hormone.

Physical & Behavioural Changes in Dogs During LH Surge

Before the LH surge begins, your bitch should display edema and redness of the vulva. She will also produce dark red and bloody discharge. As her estrogen levels drop and her progesterone rises, the edema lessens and her discharge can change from dark red to a straw color.

On the day of the LH surge or right around it, your dog’s behavior can change dramatically. She may suddenly display flagging behavior and allow other dogs to mount her. She may also flag when someone bumps into her, and she may walk around and whine. Generally, once a bitch starts standing, she is ready to breed two to three days after.

As well as obvious breeding behaviors, your bitch may go off her food or become hungrier. She may urinate more often to attract the attention of male dogs. At this time her urine will contain hormones and pheromones that male dogs can smell from great distances. As well as this, she may become more agitated, irritable, and nervous. Some bitches are the opposite, becoming more affectionate and clingy during the LH surge. You know your dogs best, so be sure to look out for any behavior that is unusual for your bitch.

How Does Dog Progesterone and LH Testing Work?

Progesterone testing should begin 3 to 5 days into your bitch’s heat, and repeated every 2 to 3 days. In order to get the blood sample from your dog, your vet will shave a small patch of fur from your dog’s neck or leg. Then, the vet inserts a small needle into your dog’s vein. This process is similar to a human blood test. As such, most dogs cope well with the procedure and do not need sedation. However, if your dog needs sedation, your vet may ask your permission to sedate your pet. A sedative reduces stress and prevents your dog from having a frightening experience.

The blood sample is then either sent for analysis in-house or to a laboratory if your veterinarian does not have all the necessary equipment. Smaller practices are less likely to have this equipment due to a lack of demand. Most vets will use an immunoanalyzer to look at your bitch’s blood sample. Some examples of popular immunoanalyzers include the Immulite® 1000 System and VIDAS®. Depending on your vet and the method they use, you may get results within 1 to 2 hours.

dog progesterone and LH testing
Your vet will get a blood sample from your dog to do the test.

What Are Ovulation Test Strips and How Do They Work?

Ovulation test strips are at-home tests that can be done to check if your dog is ovulating. These strip tests are less stressful for your bitch, are cheap, and are easy to use at home. However, some customers find that these test strips are not reliable indicators of ovulation in dogs – some strips do not change color, and some give false indications that the bitch is ready to breed. According to manufacturers of ovulation test strips, the strips work by detecting estrogen levels in the vaginal fluid of the bitch. But how do you use an ovulation test strip?

First, wipe the vulva clean and ensure that there is no excess blood. Then, gently open the vulva and place the strip 1/2 an inch inside. Make sure that the pad’s surface touches the vulva wall and hold it in place for 20 to 30seconds. After this, carefully remove the ovulation stip and check that it is completely moist with vaginal fluid. If it is, wait an additional 30 seconds for the test results to become clear. Any color change after 3 minutes is inaccurate, so make sure to read the results in this period.

Progesterone and LH Testing in Dogs – FAQs

Have any more questions or concerns about progesterone and LH testing in dogs? Feel free to refer to our Frequently Asked Questions section for more details. If in doubt, always ask your vet for advice.

How quickly does a dog’s progesterone rise?

According to Clarendon Street Veterinary Surgery, once progesterone levels start to rise, they double every 2 days. Maximum progesterone concentrations are achieved between 20 and 30 days after the end of the bitch’s oestrus, regardless of whether the bitch is pregnant or not. From then onwards, a gradual decline occurs, and progesterone returns to its basal levels around 60 to 70 days after ovulation has occurred. Overall, your bitch’s progesterone will rise very quickly, so it is important to conduct regular progesterone testing to know when to breed your dog in heat.

How do you test if a dog is ovulating?

To test if your dog is ovulating, the most accurate method is progesterone testing. With your vet’s help, measure your dog’s baseline progesterone at 3 to 5 days into her heat. At the beginning of her heat, your bitch’s progesterone levels should be less than 1 ng/mL. Over the next few days it is important to re-test your bitch. Soon, her progesterone should measure 2.0 ng/mL, or twice the baseline level.

This rise in progesterone is an indicator that an LH surge has begun, and since the LH surge only lasts for 12 to 24 hours (or sometimes less), it can be easily missed if LH the only hormone being measured. Once your vet informs you of the LH surge, be aware that ovulation occurs about two to three days after, on average. These eggs are viable for three to four days after ovulation or five to six days after the initial LH surge

How often does a dog come into season?

Most medium dog breeds come into season twice per year, around every six months. However, this interval varies from breed to breed. Smaller breeds like Chihuahuas may come into heat three times per year, while giant breeds like the Great Dane may come into heat every 12 to 18 months. Some breeds have more specific heat cycles. For example, Basenjis have a longer heat cycle than other dog breeds, and the estrus occurs between September and October for Basenjis in the Northern Hemisphere. Overall, different dogs come into season at different times, so talk to your vet about your pet if you are unsure.

What level of progesterone indicates ovulation in dogs?

Ovulation happens when progesterone blood levels reach 5 or 6ng/mL. Whether you have a small or large breed, your bitch should ovulate at around the same progesterone level as any other dog. As soon as your bitch’s progesterone levels exceed 5 ng/mL some vets will recommend natural breedings to be done as soon as possible. Although your bitch’s eggs are not yet mature, fresh semen will survive long enough in her reproductive tract for fertilization. For chilled semen breedings, however, shipments are often arranged once the bitch’s progesterone levels rise above 20 ng/mL. Frozen semen breedings can commence once progesterone levels reach 35 ng/mL.

Do I need to come every single day until ovulation occurs?

Generally speaking, progesterone testing in dogs is usually done every 2 days. If progesterone is at its basal level (<1 ng/mL), you may wait four to five days before re-resting your bitch. If progesterone levels are 2 ng/mL onwards, your bitch can be re-tested every 2 days. This is because progesterone concentrations double every 2 days.


Dog progesterone and LH testing are an essential part of timing dog breedings. To start progesterone testing and LH testing in dogs, take your dog to the vet 3 to 5 days into her heat cycle for her first blood test. From here, you can re-test every 2 days if your vet recommends doing so.