Correlation of serum progesterone levels with reproductive events and actions.
Progesterone levels
(Can vary)
Approximate day of heat cycle.
(Can vary greatly)
Event
Action
<1.0 1 - 6 Proestrus do a baseline progesterone level
1.0 - 1.9 6 - 9 Ovulation minus approximately 3 days check progesterone levels and do smears every other day. Do LH peak if using frozen semen or semen of less than optimal quality.
2.0 - 2.9 (LH peak) Early Estrus
Ovulation should occur in 2-3 days. 
Continue to follow smears and progesterone levels until level of 4.0 - 5.0 is reached. This will help insure that ovulation has occurred.
3.0 - 3.9 10 Ovulation in 1 day  
4.0 - 10.0 11 Mid estrus
Ovulation occurs ( 2 - 3 days post LH peak and/or progesterone reaching 2.0) Eggs need an additional 2 days to mature before being ready to be fertilized.
Continue to follow smears. No further progesterone levels are required.
>10 13 Eggs are ready to be fertilized. This should be 4 days after progesterone levels reach 2.0  Begin breeding if doing natural breedings or AIs with the stud dog present. Continue every other day until smears show diestrus has begun or bitch will no longer stand.
- 16 - 19 Diestrus
Indicated by change in vaginal smears and/or failure of bitch to stand for male
Do Surgical AI with Frozen or Fresh chilled