Can someone suggest possible reasons? First checked with a 30mm follicle, with uterine edema. Everybody’s happy, vet comes back 2 days later… Follicule is gone. We wait a week, check again as mare shows again signs of heat. Again, a 30mm follicule. Back on track! Two days later, follicule is gone again, but uterine edema is still present… But the mare still shows outwards signs of heat???
Possible reasons? Game plan we should consider?
Thanks!
The most likely reason is that she ovulated! 
Mares will typically not become resistant to a stallion’s advances until 24-48 hours after ovulating, as it is progesterone secreted from the newly created CL (created where the follicle was) that causes that resistance, and the levels will not be high enough to cause resistance until about 24-48 hours.
If she persists in a “ho hum” manner when teased - not truly accepting or resisting - rather than a true resistance, then it is possible that the follicle regressed rather than ovulated, although it would be unusual for it to go from a 30mm size to absolutely nothing in a couple of days. It is however possible that she is still transitional. A few mares still will be even at this later stage.
Your best bet is keep monitoring and in the event that she becomes resistant to the stallion without an identified ovulation, perform a blood-progesterone assay and if there is progesterone present at >1ng/ml she has ovulated and it was missed.
Good luck.
Similar thing here, is there a a problem with teasing too often, right now I am just waiting this out, might breed in September:lol:
That crossed my mind (that she ovulated on a small size follicule), but then I tought it would be unlikely on a follicule of that size… But who knows, artificial insemination is always full of surprises! I’ll speak to the vet today I’ll ask if he can do the progesterone test. Thanks Jos for your advice.
I was told mine had ovulated on a 30mm.
[QUOTE=Spike;5616534]
I’ll speak to the vet today I’ll ask if he can do the progesterone test.[/QUOTE]
Don’t run the test until about 5 or 6 days after the suspected ovulation - that way if it was indeed an ovulation, the mare will have well-elevated progesterone levels and there should be no mistaking it’s result.
It’s worth considering that although the majority of mares will ovulate on follicles greater than 30 mm in diameter, some will go on smaller diameter follicles - especially if there are multiple follicles present on the same ovary; that follicles do regress slightly in size immediately prior to ovulation; and that a follicle should be measured per ultrasound in two directions - narrowest and widest at 90° - and averaged, as they are not all spherical in shape.
There should have been a CL visible on ultrasound though, which shouldn’t have been missed (if it was)…
My mare was just confirmed in foal and she ovulated a 32. I wasn’t sure that she would take and I am quite pleased. This has been a crazy breeding season. 
[QUOTE=bluemoonfarms;5616661]
My mare was just confirmed in foal and she ovulated a 32. I wasn’t sure that she would take and I am quite pleased. This has been a crazy breeding season. ;)[/QUOTE]
Congrats!
edit to say, thanks for the information.
Well, I just spoke to the vet… Today there was a CL… So… indeed… We missed the ovulation, who occured on a pretty small follicule. Next time will be the good one! And we’ll be aware that she might ovulate on a unusually small follicle.
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