Progesterone testing has been used since the mid 1970's to help determine ovulation timing in the bitch.
Progesterone is produced and released in increasing amounts by the ovary before, during and after ovulation. Serial measurement of blood progesterone provides a reliable, indirect method for determining the time of ovulation in the bitch. Although many bitches will ovulate within 24 hours of the first mating, this and the use of vaginal smears are not as reliable indicators of ovulation.
Ovulation is associated with progesterone concentrations between 15 to 25 nmol L-1. Although sperm can penetrate eggs soon after ovulation, the eggs require 24 to 72 hours after ovulation to mature before true fertilisation occurs.
In normal matings, good quality, fresh, dog sperm will live in the bitch’s uterus and is capable of fertilising eggs for up to 4 to 6 days.
Whelping is expected to occur 63 +/- 1 day from the day of OVULATION.
Ovulation Timing in the Bitch