The tests vets use
| Test | What it shows | Notes |
|---|---|---|
| Progesterone blood test | Rising progesterone around ovulation | The most common method. A rise to about 5 ng/mL is widely used as the marker for ovulation. Repeated every day or two. |
| LH test | The LH surge that triggers ovulation | Ovulation follows the surge by about two days. Less often used because it needs daily testing. |
| Vaginal cytology | Changes in cell types through the cycle | Shows the stage of heat. Often used with progesterone, and to confirm diestrus afterwards. |
Why it matters for breeding
Sperm survives for days, but a dog’s eggs need a couple of days after ovulation to mature. Timing mating from ovulation rather than from the calendar gives the best chance of conception, and helps avoid unnecessary repeat matings.
What the result gives you afterwards
- A precise due date. About 63 days after ovulation, usually within a day. Use the ovulation due date calculator.
- A safe C-section window if surgery is planned, around day 61 to 63.
- A way to judge overdue. Without an ovulation date, a dog at day 68 from mating may be perfectly normal.