11/05/2022
🐶Vaginal Cytology and Progesterone Testing
We conduct and believe both are important in determining the optimal timing of mating.
Vaginal Cytology
✅Determines stage of oestrus cycle
✅Indicates infection/vaginitis
✅Indicates an approximate mating period
✅Non invasive
✅Economical
❌Subjective to interpretation
❌Multiple tests required
Progesterone Testing
✅Quantitative value
✅Indicates accurate ovulation date (which produces a very accurate due date)
✅Indicates accurate breeding period
✅Indicates potential ovulation issues
✅Detects progesterone insufficiency throughout pregnancy
✅Detects end of pregnancy whelping/uterine inertia/optimal time for elective c-sections
❌Costly
❌Invasive
❌2-5 tests are necessary to interpret accurately
Cytology – Usually sufficient for straight forward AI’s where multiple AIs are possible in fertile bi***es using good quality fresh or chilled semen
Progesterone Testing – Essential for frozen semen, essential for accurate due date, useful for fresh and chilled semen of good quality, subpar quality and semen from older dogs
The most effective way to track the cycle accurately is to use both vaginal cytology and progesterone testing. It may be useful to even track a cycle before you actually breed the bitch.
Why they work well together?
o Before ovulation in the cycle the time of day of sampling as well as long journeys/stress can slightly skew the PG to be higher. Cytology allows us to correlate the values.
o Cytology will determine the need for antibiotics
o In cases where we only have a single high blood result cytology will determine if a mating is still worthwhile or if the fertile period has passed
o For fertility investigations we use both to determine the length of cycle and the period at which the bitch ends the breeding window. For example some bi***es are most fertile at 35ng/ml and some are already gone out at this value depending on their ovulation date.
Progesterone testing is essential to ascertain the exact ovulation day allowing us to predict when is best to mate her based on the type of semen we have available. This is particularly important for frozen semen which has a short lifespan post thaw. Eggs take approximately 72 hours AFTER ovulation to reach a mature and receptive state. This information is also useful for s***m of reduced quality, s***m from older studs, chilled semen and bi***es with a history of failed matings. Cytology works very well alongside progesterone testing to correlate the information.
Image 1: Cytology of a bitch on day two post ovulation, day 13 of her cycle
Image 2: Cytology of a bitch on approx day 2 of her cycle