What does "pinching" involve, and how does vet decide which embryo to pinch?
We inseminated our mare today with 40 and 45 follicles, and vet said there's a good chance that if she settles, it will be with twins (of course, may not happen). I know that one of the embryos is typically "pinched" as soon as possible, but what exactly does this involve? How do the vets decide which one to leave viable?
Pinching is exactly what it sounds like; squeezing/putting pressure on the embryonic vesicle to crush it. Vets will pinch whichever one is easiest for them. If there is a size difference some will pinch the smaller one, some the larger one (as long as the smaller one seems healthy/growing). If no size difference then probably whichever one is most convenient for them.
When my mare had hers pinched it was about day 13. He pinched the smaller of the two, he figured it was about 2 days "younger" then the other one based on the size. They were very close together so it took some time, but with patience he was able to pinch the smaller one. If I remember we did 10 days of Regumate after and she carried to term.
OneMoreTime, I am in a similar situation. We just bred two mares last week. One had two follicles on the right side, both at 55. We are checking next Friday to see about twins. Hopefully, it won't be an issue, and if necessary, the vet will be able to pinch one. (I never had to worry about that before, so I am hoping all will go well and there is one lone embryo in there next Friday when we check!)
We had a mare who frequenty twinned. Depending on the vet, they sometimes ask you which one you want them to pinch, in case you are superstitious ("I saw the left embryo deveoping into an Olympic horse in my dreams! What? You PINCHED it????")
My answer is generally "either the smallest or the one that is easiest to reach." I am mostly hoping the most viable one is left to develop.
We also have had success following up with Regumate.
Hidden Echo Farm, Carlisle, PA -- home of JC palomino sire Canadian Kid (1990 - 2013) & AQHA sire Lark's Favorite, son of Rugged Lark.
Thanks you all! She ovulated one the day after first insemination, the other right after second insemination. Now we wait... Hope only a singleton settles, but I feel more prepared for whatever happens. Fingers crossed. Thanks again.