Semen. Fresh, chilled, frozen- How long does each last?

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AP you mentioned ages ago a method of inseminating with frozen that does not require the usual scans every 6 hours (which put a lot of vets off using frozen, especially if they are inseminating at the mare's home)! What is happening with this new method - is it becoming more widely known/available? And does it have a name?



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I suspect AP was referring to deep uterine insemination; as far as I am aware (and no doubt AP will correct me if I'm wrong) this method improves results and allows lower dose rates to be used, but doesn't buy much time. Frozen semen doesn't 'last' as long in the mare once thawed so frequent scanning to determine the optimum time is still essential.
 
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AP you mentioned ages ago a method of inseminating with frozen that does not require the usual scans every 6 hours...

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Yes indeed. This is not deep uterine insemination alone, but a programme of drug treatment and double deep insemination. It takes a lot of the stress and hassle out of using frozen semen.

Here is the protocol:

1) PG to destroy CL and initiate estrus
2) Scan until 35mm follicle present
3) Give hCG (call this time 0h)
4) Inseminate (deep uterine) at 34h
5) Inseminate (deep uterine) at 40h

Feel free to spread the word to your vets!
 
JG; here's a quick quote from Paul Loomis of Select Breeders Services (they really are industry leaders in frozen semen), from a paper of his from 2001:

"These data support the position that comparable pregnancy rates may be obtained using frozen and liquid cooled semen in a commercial setting."

Bear in mind that this was in 2001. We're 6 years further on in terms of technology, and in terms of pregnancy rates when using frozen semen.

With regards to using vapour freezing as opposed to computer controlled freezing... in 2005, Ed Squires (probably one of the best known equine fertility researchers in the world) who is based at CSU wrote a review of how modern technology has helped, and will continue to aid the equine breeding industry in years to come.

The point of controlled rate freezers, is that they allow you to change the rate of cooling down to -196 degrees C. The review by Squires says:

"They found no difference in post-thaw motility or viability for sperm cooled at any of these cooling rates."

Loomis and Squires both go on to say, in a later review, that there is NO difference in pregnancy rates between semen frozen using the "traditional" method and semen frozen using the computer controlled method.

I am not having a dig at any companies. Hence me saying that "commercial websites" (that would mean all company websites) should be read with a pinch of salt when trying to gather information about breeding (or any other service), because at the end of the day companies are there to make money, and their websites must reflect that to some extent.
 
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Yes indeed. This is not deep uterine insemination alone, but a programme of drug treatment and double deep insemination. It takes a lot of the stress and hassle out of using frozen semen.

Here is the protocol:

1) PG to destroy CL and initiate estrus
2) Scan until 35mm follicle present
3) Give hCG (call this time 0h)
4) Inseminate (deep uterine) at 34h
5) Inseminate (deep uterine) at 40h
Feel free to spread the word to your vets!

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Sounds fine - but it's not really a 'new treatment' - just a variation on standard protocol for frozen which would probably work if your mare is one of the approx. 85% who will ovulate 24-48 hours after hCG on a 35 mm follicle - with the other 15% you've probably wasted the semen.

And how many scans might you need to get to the 35mm stage? This year, we had a couple of problem mares - including a 10 year old maiden, a 17 year old who hadn't foaled for 10 years,(both retained fluid first time around) and an 18 year old who - after being easy-peasy for the last 4 years suddenly decided not to get into foal at all. So we scanned more than normal (for natural cover.)

One mare was PG'd with a 25 mm follicle - took a week to get to 35. Was hCG'd on the 35 m follicle and was STILL refusing to stand for the stallion 6 days later with a 50mm follicle. We covered her the next day, gave her L/A oxytocin 12 hours later and got a pregnancy.

Another mare was PG'd on a 35 mm follicle - it was STILL 35 mm a week later and she hadn't come into season. So we PG'd again and hCG'd her AND covered her 4 days later when a scan showed follicle was 45 and 'ripe'. Again, got a pregnancy. And these are just 2 for whom the absence of a scan prior to insemination would have resulted in no pregnancy.

And what if the mare hasn't ovulated 48 hours after hCG - even with deep uterine insemination - how long will thawed semen last in the mare??

I think that cutting a couple of scans may well prove to be false economy for MANY mare owners.
 
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Sounds fine - but it's not really a 'new treatment' -

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I didn't say it was new, but a surprising number of vets don't seem to do this, or know about it.

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...just a variation on standard protocol for frozen which would probably work if your mare is one of the approx. 85% who will ovulate 24-48 hours after hCG on a 35 mm follicle - with the other 15% you've probably wasted the semen.

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These figures are heavily exaggerated. You've widened the time frame, and increased the number of mares that don't respond to treatment, making it seem like it's unlikely to work.

Samper demonstrated that the majority of mares (94%) ovulate 36–42 h following induction of ovulation with either hCG or deslorelin if the mare is in estrus, and a dominant preovulatory follicle and endometrial edema are present at the time of drug administration.

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One mare was PG'd with a 25 mm follicle - took a week to get to 35. Was hCG'd on the 35 m follicle and was STILL refusing to stand for the stallion 6 days later with a 50mm follicle...

Another mare was PG'd on a 35 mm follicle - it was STILL 35 mm a week later and she hadn't come into season. So we PG'd again and hCG'd her AND covered her 4 days later when a scan showed follicle was 45 and 'ripe'. Again, got a pregnancy. And these are just 2 for whom the absence of a scan prior to insemination would have resulted in no pregnancy.

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Why PG on a 35mm (or even a 25mm) follicle? PG should be used on mares with follicles <30mm, or preferably <20mm.

While the use of PG may be an easy way to induce estrus, it is not without considerable complications that are often not understood and which can result in failure.

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And what if the mare hasn't ovulated 48 hours after hCG - even with deep uterine insemination - how long will thawed semen last in the mare??

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Well, as said above, 94% of mares ovulate 36-42h after hCG administration. For the remaining 6%... well, yes - these ones might pose a problem, but it's quite a small proportion. The semen won't last that long 6-18 hours I believe, but using the protocol above, or similar ones will help to give the best chance of getting a pregnancy.

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I think that cutting a couple of scans may well prove to be false economy for MANY mare owners.

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I think that scans every six hours are impractical and perhaps become preventative for many vets and breeders. I think the protocol gives a well established system for acheiving good pregnancy rates.

Would love to know your thoughts on these points
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These figures are heavily exaggerated. You've widened the time frame, and increased the number of mares that don't respond to treatment, making it seem like it's unlikely to work.

Samper demonstrated that the majority of mares (94%) ovulate 36–42 h following induction of ovulation with either hCG or deslorelin if the mare is in estrus, and a dominant preovulatory follicle and endometrial edema are present at the time of drug administration.

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No - I haven't - just quoted DIFFERENT research that showed slightly different results. And another group of researchers (lost the reference at present) showed a slightly lower % again. But it would appear that most researchers find at LEAST 10% of mares don't ovulate within 48 hours which would suggest that omitting ANY scanning after hCG reduces your chances quite a bit.

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Why PG on a 35mm (or even a 25mm) follicle? PG should be used on mares with follicles <30mm, or preferably <20mm.

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Partly because that's the size the follicle WAS at the time of scanning - with no sign of the mare coming into oestrus - but also because in our (my vet's and my) experience, PG'ing on a 20 mm follicle is usually a waste of time when it comes to inducing oestrus.

We USED to PG on a smaller follicle - say 20 mm - then after a week of teasing we'd scan again and find a 30mm follicle and no sign of approaching oestrus. I don't like using PG more than necessary - hell, I don't like scanning more than necessary (my stallion teases very effectively and is never wrong - even when the mare is shy) - but if you've got older maidens with potential fluid problems then managing the cycle is more critical.

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I think that scans every six hours are impractical and perhaps become preventative for many vets and breeders.

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I'd agree - every 6 hours could be problematic unless the mare is at a specialist AI centre - I think Jonathon Pycock suggests that every 10-12 hours after hCG should be a minimum.
 
That is a fair comment. I find Samper's figures to be most reliable taking into account the number of mares examined in his studies. However, I do accept that other figures have been found.

I certainly wouldn't say one should NOT scan at all
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that would be silly, Jonathan's suggestion on 10-12 hours seems good, but I'm sure for some places and some vets, it could again become a preventative issue.

I think we would probably both agree that :

1) frozen semen needs to be better regulated (in terms of when frozen semen should be destroyed, although this is difficult taking into account the PTM of <5% resulting in a pregnancy), and when we are better able to predict fertility of semen that has been frozen, it will be a more effective.

2) many vets and breeders need to be better educated about frozen semen, and how it can be used for maximum efficiency.

3) frozen semen has the potential to be an extremely useful for the majority of breeders in the near future

What do you think JG?
 
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I think we would probably both agree that :
1) frozen semen needs to be better regulated (in terms of when frozen semen should be destroyed, although this is difficult taking into account the PTM of <5% resulting in a pregnancy), and when we are better able to predict fertility of semen that has been frozen, it will be a more effective.

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Yep - and I think there needs to be FAR more information available about the quality of frozen semen - particularly things like the 1st cycle success rate. Success figures are often quoted over 3 cycles (and then look good!) but I sure wouldn't be happy using frozen if a majority of mares were taking 2-3 cycles to conceive. Makes it a veryu expensive exercise - quite apart from mares getting later and later.

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2) many vets and breeders need to be better educated about frozen semen, and how it can be used for maximum efficiency.

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Agreed - and I think those selling frozen semen should ensure that the buyers and their vets know how to use it successfully - and then stand by it - rather than leaving the buyer with a massive gamble. (I've decided NOT to go ahead with frozen from one stallion because the deal was: 2 straws cost £xxx. No guarantee at all. No more straws if you need them (unless you pay another £xxx) BUT, if you get mare in foal with one straw, you have to return the other. A win/win situation for the semen owner - the mare owner can just hope and pray.)

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3) frozen semen has the potential to be an extremely useful for the majority of breeders in the near future

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Agree 100% - although the first two points could be limiting factors. Mare owners need to have confidence that they stand a reasonable chance of success - provided they do it properly.

From my point of view, breeding Irish Draughts, where there is a relatively limited number of stallions 'suitable' for any mare because of narrowing bloodlines, frozen looks very attractive to get outcrosses. But the risks - and costs - and the need to send mares away to a reputable AI centre - means I won't use it much at this stage - despite real difficulty finding suitable stallions available by chilled semen (which we can 'do' at home and I would therefore prefer - I don't trust ANYONE to look after my babies as I would!)
 
Back to the issue.......

My mare was inseminated by our vet after we bought frozen semen to preserve bloodlines. The stalion had been dead 6 years so as long as it is stored, transported and thawed correctly my yearling is proof that it works!!!!
 
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