My mare was bred yesterday with shipped semen. on a 45 soft and sore. Today she has OV'd but has a second follicle, now 35. she is still teasing very hot but has lost the edematous look. we will check her again tomorrow, but the vet says he never breeds a second follicle. I was surprised. I thought conventional wisdom was to breed both if the mare stays in estrous.
I have been retired from breeding for 9 years. has this changed? is there evidence that the first follicle is more fertile? i'm sure he wants to avoid twins, but won't this lower the odds if we stop now? and if the second follicle doesn't OV fast, aren't we in danger that the uterus will not be ready when the embryo is transported out of the oviduct at day 6?
It is extremely unlikely that the mare will remain in estrus for more than about 48 hours at most after the primary ovulation. The CL that forms in the area evacuated by the ovulating follicle (after ovulation) secretes the hormone progesterone which causes a negative response to the stallion's advances once levels are adequately high, which is usually about 24-48 hours after the ovulation. As sperm are viable for 48-72 hours in the uterus (or more correctly the oviducts), it is likely that the second ovulation will still occur at a time when there are viable sperm present anyway. Additionally, progesterone causes the cervix to close and uterine immune response to be depressed, so breeding 24-48 hours after ovulation could result in semen and all the associated "nasties" that go in there with it being placed in a uterus with no way to be expelled.
Thank you for your response and information. After years of retirement, all those facts that used to bounce around in my head are a little fuzzy.!!
i should have included: it was shipped semen, sent saturday, arriving monday. First OV Tuesday. so if the second one blows, tomorrow (Wed) or the next day (Thurs), i worry that the semen will no longer be still good, but you never know. also the stallion is 17 years old, i think. i do agree if the cervix closes down, breeding would be bad idea though. Since they also told me the edema had faded, that is likely to be the case. She is a maiden (10 years old) with a tight cervix, so it's hard to evaluate it.
timing less than ideal, as the farm gave her prostin on a monday, without my knowledge. We always considered monday prostin to be against the law when shipping is involved!! LOL
I have moved to an area with no big breeding farms, and few good breeding vets. Hence i hauled her elsewhere, and am not there to see and hear everything. A hard position for a hands on person like me!!
Well, responses to prostaglandin will vary tremendously upon what is on the ovary at the time of treatment (i.e. if there are follicles present and if so how large). In fact some research presented at the 2002 ISER (can't remember the author[s]) demonstrated that the average interval from treatment to ovulation was 9.5 days, so giving it on a Monday would actually be ideal! There is no doubt in my mind though that if I want to reliably time an ovulation, I'm not going to use Prostaglandin F2α but P&E or biorelease altrenogest...
WE used prostin on hundreds of recipients. they were all 6-8 days post OV. the average time was 8 days to OV. which is exactly what this mare did this time. of course she isn't usually so by the book.
Her second OV occurred just one day later, so we are stuck worrying about twins. she will be checked at day 13/14 or 14/15. if they have to pinch one, i want to catch it before they stop travelling. doesn't that occur at 15 or 16? i'm getting old and haven't used these facts in 9 years now!!! ha ha
is the biorelease altrenogest different from the implant Bob Douglas used to rave about?
Well, even at 8 days, Monday is still a good day to give Prostaglandin F2α as a Tuesday ovulation, so collect and ship Monday!
Twinning increases the chances of a singleton pregnancy dramatically, so as long as one has the technology available to reduce, it's a good thing!
Not sure what the "implant" was that Bob used to rave about, but the biorelease medium was developed by a friend of Bob's (and mine) and is marketed through BET pharmacy, so it may be related to it, if not the same thing.
cool!!! could well be the same thing. I used to pick Bob's brain a LOT!!!!
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