Progesterone timing for optimal breeding
How serum progesterone maps to the LH surge, ovulation, and the fertile window in the bitch.
Serum progesterone is the most reliable indicator of the LH surge and ovulation in the bitch. Understanding its dynamics is central to timing natural mating, fresh, chilled and frozen semen inseminations.
- The LH surge in the bitch typically occurs when serum progesterone reaches ~2–3 ng/mL.
- Ovulation follows the LH surge by approximately 48 hours, at progesterone concentrations of ~4–8 ng/mL.
- Canine oocytes require an additional 48–72 hours to complete meiosis and become fertilizable.
- Frozen semen fertility windows are narrower than fresh semen and are typically timed 2–4 days after ovulation.
Physiological background
Unlike most mammals, the bitch ovulates primary oocytes that must mature in the oviduct before fertilization is possible. This unique biology is the reason progesterone — secreted by luteinizing follicles even before ovulation — is such a useful surrogate marker for the reproductive events that matter clinically.
Interpreting the curve
Progesterone rises from a baseline of <1 ng/mL during anestrus. A rise to 2–3 ng/mL closely tracks the LH surge; 4–8 ng/mL is broadly compatible with ovulation; and values above ~20 ng/mL are typically seen a few days after ovulation, once the oocytes are fertilizable.
Practical implications
Timing decisions should be made by a licensed veterinarian based on serial quantitative progesterone, vaginal cytology, and — where appropriate — ultrasonography. Single measurements are rarely sufficient.
References
- Concannon PW. Reproductive cycles of the domestic bitch. Anim Reprod Sci. 2011.
- Kutzler MA. Estrus induction and synchronization in canids and felids. Theriogenology. 2007.
- Root Kustritz MV. Clinical canine and feline reproduction: evidence-based answers. Wiley-Blackwell.
Educational information only. Does not replace veterinary consultation. No diagnosis. No prescriptions. No emergency advice.