Progesterone Timing Tracker for Dogs

Last Reviewed: May 16, 2026. Built and reviewed by the BreederHQ Operations Team, working with active dog breeders and reproductive veterinarians.

Log your P4 results in cycle order, see the trend across readings, and bring organized data to your reproductive vet. This is a planning and visualization tool, not a veterinary diagnostic. The actual breeding decision belongs to your vet, working from the full P4 trend and your dam’s history.

Log a Progesterone Cycle

Anchor with the heat-start date, then add P4 readings as they come back from the lab.

How to Use This Tracker

1 Set the first day of heat. That anchors the day-of-cycle on every reading. If you’re between two possible dates, use the earlier one.
2 Add each test result. Enter the date of the draw and the P4 value in ng/mL. Add a new row for each test as they come back.
3 Read the trend, not a single number. Direction and rate of change matter more than any one value. The timeline shows readings in cycle order so the trend is visible at a glance.
4 Share the trend with your vet. Optimal breeding timing is a veterinary judgment call based on the full trend, the method, and your dam’s history. Bring the data, let them call the day.

What the Numbers Generally Mean

Baseline (Under 1 ng/mL)

Early in the cycle. Often consistent with proestrus or the start of testing. The job here is to establish a baseline, not to decide anything yet.

LH Surge Range (Around 2 ng/mL)

Values often consistent with the LH surge in dogs. This is the point most repro vets use as a reference for counting forward to peak fertility. Sample cadence usually tightens to daily here.

Ovulation Range (Roughly 4 to 10 ng/mL)

Values commonly consistent with ovulation. The eggs released still need to mature before they are fertilizable, which is why optimal breeding usually comes a couple of days after ovulation, not on the same day.

Post-Ovulation Maturation (Higher Values)

Continued rise. Timing within this window depends heavily on method (natural vs fresh chilled vs frozen) and on the full P4 trend leading in. This is where your reproductive vet earns their fee.

Values, units, and reference ranges vary by lab assay and by sample handling. A 5 ng/mL on one assay is not always equivalent to a 5 on another. Use the trend across multiple readings from the same lab, and let your vet calibrate to that lab’s reference ranges.

How Method Changes the Conversation

Natural breeding. The most forgiving. Live cover typically spans several days, and viable sperm persist in the reproductive tract for a meaningful window. Most repro vets are comfortable with a wider day-range here.

Fresh chilled semen. Less forgiving. Sperm motility and viability drop with chilling and transport time. Timing usually targets a tighter window closer to peak fertility.

Frozen semen. The most timing-sensitive. Thawed frozen sperm have a short lifespan, often only hours. Cycles using frozen typically test more often, and inseminations are often surgical or trans-cervical, placed close to the fertile peak.

Not sure yet. That’s fine. Test, log the trend, and discuss method with your vet alongside the data. You don’t need to have method decided to start tracking.

Why This Isn’t a Breeding Decision Tool

Optimal breeding timing depends on the shape of the entire P4 curve, the rate of change between draws, the lab’s reference ranges, the method, the male’s availability, and anything specific to this dam’s history. A single number, or even a calculator’s opinion, cannot replace that.

The job of this tracker is to make the trend visible and the data organized. The job of your reproductive vet is to interpret it and call the day. Treat your vet’s interpretation as the source of truth.

Read more in Progesterone Testing in Dogs and the Heat Cycle Tracking guide.

Frequently Asked Questions

What does this progesterone tracker actually do?

You enter the first day of heat and your progesterone test results as they come back. The tool plots them on a trend chart, estimates the LH surge date (where P4 crossed ~2 ng/mL), estimates the ovulation date (where P4 crossed ~5 ng/mL), and projects a breeding window based on method (natural, fresh chilled, or frozen). With only a couple of readings these are interpolated estimates that refine as you add more data. It is a planning and visualization aid built around standard canine reproductive ranges. It is not a veterinary diagnostic, and your reproductive vet is the source of truth on the actual breeding date.

What do the progesterone ranges mean?

Under 1 ng/mL is generally considered baseline or very early in the cycle. Around 2 ng/mL is the range where the LH surge often occurs in dogs. Roughly 4 to 10 ng/mL is the range where ovulation commonly happens. Above that, the eggs continue maturing and become fertilizable a few days after ovulation. These are general framing values, not decision thresholds. Different labs, sample handling, and individual dams all shift the numbers. Your reproductive vet is the source of truth on what your specific results mean.

Why does the tool not just tell me when to breed?

Because that is a veterinary judgment call, not a calculator output. The optimal breeding day depends on the progesterone trend across multiple draws, the breeding method (natural, fresh chilled, or frozen), the male’s availability, the lab’s reference ranges, and any history specific to your dam. A single number out of context is not enough. The tool surfaces the trend and the general interpretation. Your vet decides the timing.

How does breeding method change the timing?

Natural breedings are forgiving, since live cover spans several days and sperm survive in the reproductive tract. Fresh chilled semen is less forgiving and is typically used closer to peak fertility. Frozen semen is the most timing-sensitive, since thawed sperm have a very short lifespan and need to be deposited very close to the fertile window, often via surgical or trans-cervical insemination. The tracker lets you note the method so your vet has full context, but the actual timing decision still comes from your repro vet.

How many tests should I run during a cycle?

Most programs start with a baseline draw early in proestrus and then test every two to three days, tightening to daily as values rise. Frozen-semen cycles tend to test more often to catch the LH surge precisely. Your repro vet will recommend a cadence based on the trend they are seeing. The tracker can hold as many readings as you log.

Does this tool save my data?

No. Everything you enter stays in your browser tab and disappears when you close it. Nothing is sent to a server, nothing is saved to an account, and nothing is shared. If you want to keep a progesterone history per dam across cycles, log the values in BreederHQ. That way they live alongside her heat cycle history, breeding records, and litter outcomes for next time.