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  1. #1
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    Default Frozen Semen Dose Question

    Are there any statistics that show whether conception rates are improved by using two doses of frozen semen, before and after ovulation, as opposed to using just one post ovulation ?
    Thanks !



  2. #2
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    Quote Originally Posted by Elfe View Post
    Are there any statistics that show whether conception rates are improved by using two doses of frozen semen, before and after ovulation, as opposed to using just one post ovulation ?
    Thanks !
    If using the timed insemination dose with two doses of semen, the conception rates are comparable to breeding within 6 hours post ovulation. If using one dose and splitting it to use the timed insemination protocol, success rates are slightly lower. Hope that helps!
    Equine-Reproduction.com Now offering one on one customized training!
    Leg-Up Equestrian Assistance Program, Inc. A 501(c)(3) non-profit charity



  3. #3
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    Thanks; that is a useful statistic.
    Mystic Owl Sporthorses
    www.mysticowlsporthorses.com



  4. #4
    Elfe is offline Working Hunter Premium Member
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    Quote Originally Posted by Equine Reproduction View Post
    If using the timed insemination dose with two doses of semen, the conception rates are comparable to breeding within 6 hours post ovulation. If using one dose and splitting it to use the timed insemination protocol, success rates are slightly lower. Hope that helps!
    Thanks !
    The reason I am asking is that I am about to send two mares to a clinic for insemination with frozen. On the clinic's website it states that they prefer to have two doses of semen per insemination, which makes me wonder why. Obviously two doses of frozen increases my cost and if the mares don't conceive I have no more semen !



  5. #5
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    Quote Originally Posted by Elfe View Post
    Thanks !
    The reason I am asking is that I am about to send two mares to a clinic for insemination with frozen. On the clinic's website it states that they prefer to have two doses of semen per insemination, which makes me wonder why. Obviously two doses of frozen increases my cost and if the mares don't conceive I have no more semen !
    HA! I'd prefer having two doses of semen too. It would mean that I would get to sleep and not have to do middle of the night checks :P. Hence the reason they prefer two. If done correctly, you give the mare a shot of hCG or Deslorelin say at 5 p.m. when she has a 35 mm follicle. Inseminate at 5 p.m. the next night and then you can inseminate 16 hours later or 9 a.m. the next morning . See why people LIKE doing timed inseminations?

    We do it the old fashion way here and check every six hours. Of course, this time of year, I'm not particularly warm and fuzzy to be around. Sleep deprivation is a TERRIBLE thing !
    Equine-Reproduction.com Now offering one on one customized training!
    Leg-Up Equestrian Assistance Program, Inc. A 501(c)(3) non-profit charity


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  6. #6
    Elfe is offline Working Hunter Premium Member
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    Quote Originally Posted by Equine Reproduction View Post
    HA! I'd prefer having two doses of semen too. It would mean that I would get to sleep and not have to do middle of the night checks :P. Hence the reason they prefer two. If done correctly, you give the mare a shot of hCG or Deslorelin say at 5 p.m. when she has a 35 mm follicle. Inseminate at 5 p.m. the next night and then you can inseminate 16 hours later or 9 a.m. the next morning . See why people LIKE doing timed inseminations?

    We do it the old fashion way here and check every six hours. Of course, this time of year, I'm not particularly warm and fuzzy to be around. Sleep deprivation is a TERRIBLE thing !
    I kind of thought so, but wanted to make sure that there wasn't a more "scientific" reason ! Of course if timed insemination gives you that much leeway, why bother taking the mare to a clinic ?



  7. #7

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    Using two doses of frozen semen is virtually always because the veterinarian or technician is using the timed protocol. The timed protocal is a hormonally manipulated method where the follicle reaches a certain size, then a dose is put in and the mare is given an ovulating agent. Twelve hours later, the mare is checked again and the other dose is put in. If she has not ovulated at that time she is given another injection of ovulating agent. The reason vets usually want two doses is they don't have to get up all night. There is good science indicating that using two doses is counterproductive because of the increased inflamatory response to seminal fluid. In my opinion, two doses per cycle is always overkill, especially when it is expensive frozen semen. There is also the risk with the timed protocol that the sperm might die before the mare ovulates in that 12-hour window, or the mare might regress the follicle. For these reasons I strongly advise my clients to always request post ovulation insemination. Extra ultrasounds and after hours calls are usually cheaper than more frozen semen. Plus, access to more semen from foreign stallions is sometimes an issue.


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  8. #8

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    Hi Folks,

    Happy to join the conversation. I know Kathy and Carol won't mind me adding my two cents, since we're all advocates of frozen semen here. I can also contribute some data from studies comparing one vs two dose insemination protocols.

    The timed insemination protocol was developed to minimize mare management costs associated with the repetitive checks required when breeding with one dose post ovulation. Yes, this makes it more convenient for the veterinarian, but it wasn't designed simply for their benefit.

    The concept of selling frozen semen by the dose encourages mare owners to use only one dose per cycle. Everyone knows that at SBS we advocate selling frozen semen as a breeding and providing two doses per cycle. Still we appreciate that in Warmblood circles buying imported frozen semen by the dose is the norm and with expensive semen, one dose per cycle maybe your most cost effective option. Although that does depend upon the veterinarian's management fees vs the cost of the semen.

    The two dose insemination protocol is outlined here.

    You may also be interested in our Blog articles:
    - The pros and cons of one or two dose insemination protocols
    - Frozen semen - Sell by the dose or as a breeding

    There have been many research studies demonstrating comparable results between one vs two dose insemination protocols. In fact some studies even show a higher pregnancy rate when using the two dose protocol. In our own study we found a per cycle pregnancy rate of 47% for one dose post-ovulation and 46% for two dose timed insemination. This study was using frozen semen from varied sources and 250-280 mares in each treatment group. For more info see:
    AI Using Cooled and Frozen Semen

    The two dose protocol did not result in more uterine fluid or inflammation. See our blog article for more info on this topic:
    The Facts About Frozen Semen and Post-Breeding Uterine Fluid
    Also - Factors Affecting the Uterine Inflammatory Response to Semen

    Regards
    Julie
    Select Breeders Service



  9. #9
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    It depends...
    The reasons for one vs two doses of semen are based on several factors:
    1) expense of the frozen semen per dose;
    2) experience of the professional doing the examinations for ovulation and breeding
    3) quality of the frozen semen once thawed

    1- if you can afford two doses, buy them; or if the stallion's semen is sold as a 'breeding' as with Select Sires above, do that.
    2- there is no arguing that experience always trumps inexperience.
    3- not all stallions are equal and neither are doses of their frozen-thawed semen; unfortunately, this cannot always be determined prior to breeding your mare other than to contact others that have used the same stallion or if the facility providing the semen can and will share their conception rate results;

    That said, I have gotten mares pregnant with half-doses of frozen semen and have not gotten others pregnant with more than two doses in the same breeding cycle. So it boils down to expense, timing, professional expertise, quality of the semen/stallion, and then the mare, who has her own inherent influence as well!

    Conception will occur if there are a sufficient number of viable (aka, living and able to fertilize) sperm in the vicinity of the ovulated ovum (or ova) at the appropriate time. In some cases a half dose is adequate, and two doses may be overkill, in others it would not matter if there were 6 or 7 doses!

    So an answer to your query is nearly impossible other than to say, "it depends...!"
    VAhorsevet


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  10. #10
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    I have not used a full dose of frozen semen for some years now

    i am not a vet, but do all my own repro work

    Here in Australia we can buy semen from PSI by the dose and get as many pregnancies from that dose as we like

    we can also buy semen from other stations in this way, but not all

    So all of my own pregnancies in the last few years have been from one straw only, sometimes 2 but rarely

    I do not use the 6 hour window though.

    if i have a mare set up for ovulation at midday, i will check her early morning, if the follicle is there and looking good, i will check at 9 am, 11 am, 1 pm, so we are talking about a 2 hour window only

    If it all looks good i will often put the 1 straw in at 10 am, so it is in the mare for 2 hours before ovulation, and this has been very successful

    i cannot imagine why you would need to use more than half a dose with the timed protocol, where you know the semen is good, such as from PSI

    The only reason i initally got into using the 1 straw was that often i would use three-quarters of a dose in a mare and have only 1 straw left

    i had mares that did not take to the three quarter dose, but when i put the 1 straw in, they went in foal

    now i only ever use 1 straw, where i am confident that the semen is good quality

    Paulamc


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  11. #11
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    Quote Originally Posted by paulamc View Post
    I have not used a full dose of frozen semen for some years now

    i am not a vet, but do all my own repro work

    Here in Australia we can buy semen from PSI by the dose and get as many pregnancies from that dose as we like

    we can also buy semen from other stations in this way, but not all

    So all of my own pregnancies in the last few years have been from one straw only, sometimes 2 but rarely

    I do not use the 6 hour window though.

    if i have a mare set up for ovulation at midday, i will check her early morning, if the follicle is there and looking good, i will check at 9 am, 11 am, 1 pm, so we are talking about a 2 hour window only

    If it all looks good i will often put the 1 straw in at 10 am, so it is in the mare for 2 hours before ovulation, and this has been very successful

    i cannot imagine why you would need to use more than half a dose with the timed protocol, where you know the semen is good, such as from PSI

    The only reason i initally got into using the 1 straw was that often i would use three-quarters of a dose in a mare and have only 1 straw left

    I had mares that did not take to the three quarter dose, but when i put the 1 straw in, they went in foal

    now i only ever use 1 straw, where i am confident that the semen is good quality

    Paulamc
    This is EXACTLY what my new repro vet does. It's been interesting to watch this young vet work - and the effort he puts into scheduling perfect timing. I knew I was meticulous, but he takes the cake. Whether fresh or frozen, this vet wants the semen in the mare so it's approx. 2 hours prior to ovulation. He also doesn't like flooding the mare with a lot of semen, says it just more for her to have to clear and he has had far better success using minimal amounts as close as possible prior to ovulation. He checks the semen before inseminating and, if the sperm seem less progressively motile than he likes, he would prefer doing deep horn rather than flooding her uterus with more semen. My first year with this vet, although he trained with my old repro vet who had superb results, so we'll see - proof in the puddin'.
    https://www.facebook.com/MariposaSportHorses

    Practice! Patience! Persistence!


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  12. #12
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    Quote Originally Posted by rodawn View Post
    This is EXACTLY what my new repro vet does. It's been interesting to watch this young vet work - and the effort he puts into scheduling perfect timing. I knew I was meticulous, but he takes the cake. Whether fresh or frozen, this vet wants the semen in the mare so it's approx. 2 hours prior to ovulation. He also doesn't like flooding the mare with a lot of semen, says it just more for her to have to clear and he has had far better success using minimal amounts as close as possible prior to ovulation. He checks the semen before inseminating and, if the sperm seem less progressively motile than he likes, he would prefer doing deep horn rather than flooding her uterus with more semen. My first year with this vet, although he trained with my old repro vet who had superb results, so we'll see - proof in the puddin'.
    It will be interesting to see how this young vet changes his practice when he has 10 some mares to check!

    Like Paul, I would do this with my own mares, as I only breed 1-3 per year. But I'm not trained in ultrasound. However, right now, MY time is free.


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  13. #13
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    Not really sure why you equate young with not busy. He's extremely busy. This is SB/TB/QH/WB country! Where we all had to ship to Calgary or Edmonton for service, now he's got the entire market himself. I have 11 to do this year, my neighbor has some 30. That 2 clients within 10 km of his house! It's the fact he is so busy why he puts so much effort into planning the timing. Actually, I'm feeling rather reassured about this young man. My neighbour told me he's 10 for 10 so far, so I'm very happy with that. He worked some time at Spruce Meadows, so I was expecting him to know a thing or two about it.
    https://www.facebook.com/MariposaSportHorses

    Practice! Patience! Persistence!


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  14. #14
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    I am jealous, Rodawn...
    Good luck this year.



  15. #15
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    Quote Originally Posted by paulamc View Post

    I do not use the 6 hour window though.

    if i have a mare set up for ovulation at midday, i will check her early morning, if the follicle is there and looking good, i will check at 9 am, 11 am, 1 pm, so we are talking about a 2 hour window only

    If it all looks good i will often put the 1 straw in at 10 am, so it is in the mare for 2 hours before ovulation, and this has been very successful
    Overkill and not necessary. Research shows that if you have good quality semen and inseminate within that 6 hour window, your pregnancy rates are no better when checking more frequently. And something to consider, as well. EVERY time you go into a mare rectally, you run the risk of tearing her. Some mares are exceptionally tolerant, but we do have some that after a few goes, they're not quite as happy to see you, even with a bucket of grain sitting in front of them.

    i cannot imagine why you would need to use more than half a dose with the timed protocol, where you know the semen is good, such as from PSI
    The caveat is GOOD semen. And, define good! Some stallions have exceptionally fertile semen, but may not have the most beautiful looking motility. Others will have super motility, but ho hum fertility. Determining what "is" an insemination dose is also a bit tricky and there are varied opinions on the subject, as well. With uber fertile semen, I'd be willing to take a risk on splitting the dose, but with a younger stallion without the track record behind him, you may split the dose and end up with nothing instead of two . But I work for the mare owner and will do what they wish...well..except for the every two hour thing !
    Equine-Reproduction.com Now offering one on one customized training!
    Leg-Up Equestrian Assistance Program, Inc. A 501(c)(3) non-profit charity



  16. #16
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    I am fully aware about the rectal thing, and its not that much scanning really, just a few the morning of ovulation

    as i am only working with 1 straw and not a full dose, it has to be as close to ovulation as possible

    when i was using vets who all did the 6 hours after thing, i had the most awful success rates

    however i am sure that was just my vet and there are much better ones around obviously

    as we are sold the semen in this way and encouraged to get as many pregnancies per dose as we can, i much prefer to use the 1 straw of course where the semen is excellent

    i am not sure that you can buy it over there in this way so there is no point to it

    but the point is, one straw is plenty of semen to get a mare in foal, rather than using full doses

    i have put 1 straw in at night also where i thought the mare was going to ovulate overnight, not knowing when ovulation was really going to occur and the overnighters have usually always been successful as well
    the next morning the mare has ovulated in these cases and there has been no CL in the morning, so the semen was still good for several hours inside the mare

    i am only doing my own mares and they are a very fertile group for frozen semen, i must point that out

    Paulamc



  17. #17
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    Quote Originally Posted by Equine Reproduction View Post
    If using the timed insemination dose with two doses of semen, the conception rates are comparable to breeding within 6 hours post ovulation. If using one dose and splitting it to use the timed insemination protocol, success rates are slightly lower. Hope that helps!
    http://selectbreeders.hs-sites.com/b...m_medium=email

    So which is it? Slightly lower or higher? (when using one dose and splitting it to use the timed insemination protocol)



  18. #18
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    I can't understand why the pregnancy rates in that study are so low?
    www.svhanoverians.com

    "Simple: Breeding,Training, Riding". Wolfram Wittig.



  19. #19

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    For those interested in splitting doses of frozen semen I will direct you to the following articles for more information:

    Splitting Doses of Frozen Semen

    And the Comments section of this blog article:
    The Pros and Cons of 1 or 2 dose Insemination Protocols

    The challenge with splitting doses of frozen semen is that not all frozen semen is created equally, and it is important you know how many total sperm are in the breeding dose before splitting. Also it is wise to have fertility of the frozen semen confirmed with a full breeding dose before splitting.

    To respond to Donella's query about the pregnancy rates being low. The data presented in the blog article Effect of Number and Timing of Equine Frozen Semen Inseminations on Fertility is not end of season pregnancy rate, but per cycle pregnancy rates. This data represents a large number of breeding cycles (1871 cycles) performed on multiple breeds of horses at several SBS affiliate labs in the US and Europe. As you can imagine, there would be a wide diversity in the quality of semen used. Also mares may not have been managed for the full season at the clinic, they may only be represented for one breeding cycle. Therefore, we can only report on the pregnancy rates per cycle, which is going to be less than the end of season pregnancy rate.

    Having said that, a per cycle pregnancy rate of 46-54% is not necessarily "low". Here is an article that presents some data for comparison:
    A Review of Reports for Reproductive Efficiency
    With natural service in the TB breeding industry the per cycle pregnancy rates were about 62%. This is for natural service, so rates with cooled or frozen semen would be expected to be lower.

    Remember this data reflects a very large number of mares and a large variability in the semen being used. So individual stallions may have a much higher pregnancy rate per cycle than reported in this study, and you may have experienced a higher rate with your own mares. But the benefit of large data sets like this is that it shows you what is normal for the industry as a whole. Often we get caught up with what we would consider "normal" for our own breeds and disciplines, or your own mares or stallions, but this may not be the norm for the breeding industry, all breeds, all mares and all semen quality considered.

    I hope this helps answer your questions. Let me know if you wish to expand upon this further.

    Julie


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  20. #20
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    My vet also us closer to two hours. On the older mares he prefers to inseminate within an hour of ovulation. If you take out my problem mare (who did end up getting in foal with fresh), he did have a 100% first cycle pregnancy with frozen on older sporthorse mares. I will take it


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