Does anyone have an educated guess as to what my mare's chances of taking are with the following circumstances?
1. Stallion supposedly has 60% motility after 50 hours and actually causes many mares to conceive twins because his semen has incredible longevity.
2. Container most likely failed during shipment, causing only 25% motility in the sample upon arrival (samples were tested at various temps- no improvement). 1 billion cells were shipped, and according to the university doing the insemination, they appeared to be properly extended. Semen report was included with shipment identifying good motility etc. at time of shipment. Equine Express disposeable shipper was used.
3. Mare double-ovulated (two eggs released) within about 12 hours of being inseminated. Maiden mare had clean culture, good uterine clearance and was by all appearances in perfect breeding health. 24 hours after insemination, there was another follicle looking like it *might* release (the HCG apparently did its job VERY well).
Any guesses as to her chances of taking? She would have received about 250 million motile sperm (progressive motiliy was somewhat less).
Erica I would say the chances are approximately 1 in 250 million. I say that because it only takes one and all the rest would have been expelled in the stall bedding or on the ground.
HP
Jos (142.177.104.202)
Posted on Sunday, May 12, 2002 - 09:35 am:
Research has indicated that there is only a marginal reduction in pregnancy establishment with inseminations down to 100 million sperm (the optimal being 500 million) as long as timing is correct (<24 pre-ovulation), and we prefer to go no lower than 200 million. Pregnancy is therefore likely assuming all else is OK, and the semen was not too old at insemination (you don't indicate how old it was).
Note that a stallion doesn't "cause a mare to conceive twins" - the mare must have a double ovulation.
Good luck.
esiverts (63.49.180.23)
Posted on Wednesday, May 15, 2002 - 12:12 pm:
Wow! Thanks so much, Jos!
I was sort of in the doldrums, thinking that my mare would not likely conceive, because the vets told me they generally prefer to get at least 500 million to 1 billion progressively motile sperm.
The final report I received indicated she was inseminated with 270 million progressively motile sperm (which had been collected about 24 hours prior to insemination), so it sounds like she actually had a decent dose.
Regarding the twinning, I understand that the mare would have had to ovulate twice. I was actually referring to a comment that the stallion owner made, which was that his sperm has such longevity that mares that have double-ovulated with 24-48 hours between have had a high rate of twin pregnancies.
So thanks for lifting my spirits guys!
-Erica.
ps. Does anyone know if research has been done to determine if there is an increased chance of conception with a double-ovulation?
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