I'm having trouble getting a mare in foal. She's 14, and has had 2 previous foals, but was open last year. When we get the 2 doses of semen, my vet likes to put both of them in the mare at the same time, instead of breeding her on 2 different days. He says the mare does a better job than the Equitainer at "storing" the semen. Thoughts on this? Which method is more likely to result in a pregnancy?
Hi Rachel, This is a big area of controversy for breeders vs. vets...especially for those who've been breeding for years on their own, etc. My mare is now being bred (was today actually), ....my repro vet and the breeding manager at the farm my mare is at got in an argument about this topic! Breeding manager wanted to hold 2nd dose of semen, and breed later in the day (or following day, whatever). Repro vet states that the semen is most VIABLE in the mare. Breeding manager states they have 'always done it the other way and have had good conception rates'. Now, I'm not a vet, but I have to contend that a board certified theriogenologist probably has the most correct, up to date information and research...I pay this person to do a job, and expect those who assist her to follow her direction. So, vet trumped manager on this one.
I've done my own research to educate myself on this topic, and all of it seems to contend that the fragility of semen is temperature and environment specific. Semen can survive extended time in the reproductive tract of a mare, but a warming equitainer subjects the semen to temperature changes, hence reduction in conception rates.
Research has shown that breeding with an insemination dose >500 million progressively motile sperm does not increase pregnancy rates. From that, we can extrapolate that putting both the insemination doses in the mare will not double - or necessarily increase - the chances of pregnancy establishment...
OTOH, in the event that one is breeding a mare that has delayed uterine clearance issues, inseminating with twice the volume may in fact reduce the chances of establishing a pregnancy, as the increased volume of fluid put into the uterus may result in such an amount of fluid that the already-compromised uterus is unable to clear the excess fluid.
Research has also shown that insemination of a second dose of semen ~16 hours after the first without seminal plasma content results in destruction of the sperm by the uterine inflammatory cells; but insemination with semen containing only sperm and seminal plasma (i.e. no extender) results in good pregnancy levels establishment. Now, with cooled semen, there are neither of these situations present, as the semen contains seminal plasma (the mitigating component), but it is dramatically diluted by semen extender. So... inseminating a second insemination dose ~16 hours after the first will typically result in many of the sperm being destroyed, although a few might get through to the oviducts.
In the event that the second insemination dose is held until at least 24 hours after the first prior to insemination, the inflammatory cell presence in the uterus should be significantly reduced by then, and hence, a good number of viable sperm introduced at that time should be able to make it through to the oviducts.
The protocol that we follow is to inseminate the second dose at least 24 hours after the first, but only after we have warmed a sample and looked at it to confirm that there are still a good percentage (>10%) progressively motile sperm available.
We have seen good pregnancy establishment rates by following this protocol, but we recognise that the argument will probably be going on as long as cooled transported semen is in use...
The bottom line is, are you getting the pregnancy rates you desire using the current protocol? If not, then something probably needs changing...
Jos, I too had heard recently about the >500 motile sperm insemination volume. This is actually (i believe) good news! You are entirely correct that there will always be debate regarding protocal for cooled transported semen....breeders and vets will always have some differing opinions. Either way...my durn mare isn't being cooperative, and I'm frustrated as she didn't ovulate as anticipated and the insemination....well, you know how it goes, so we are ultrasounding like crazy and may have to do a counter to counter. Mares....
Hey Jos, Since we're on the subject...any suggestions for this one: Mare palpated last Wed: 25 mm follicle Mare palpated this Mon: 40 mm follicle (very soft) Mon: ordered semen (next day) Tues: inseminated & gave HCG (only 1 insemination, farm unable to ship 2) Wed: Ultrasounded, has not ovulated!!!! Big follicle, even more soft, vet feels that she was readily approaching ovulation, no edema. vet coming out in the morning tomorrow to re ultrasound in hopes that she has ovulated.
Repro vet discussed with stallion manager re: semen quality/viability. They had sample of semen sent to us in lab (as shipping tester), and semen still rates high (don't know the #'s off the top of my head) today. If she has ovulated by Thurs 8 am, the theory is to wait and ultrasound at 14 days. If not, continue ultrasounds, and do counter-to-counter if at all possible. If you have time, your thoughts would be great. p.s. since I was not there when she was AI'd, I do not know what the semen count was.
When you say you have "a 40 mm follicle" based on manual palpation, there is of course the chance of there being 2 or more smaller follicles in close proximity...
Ok, then on Wed, ultrasound did reveal a "big" follicle. What is "big". Mares can build really big follicles this time of year - 60-70mm, so a 40 mm follicle may not mean anything for her just yet.
More importantly, what is the shape of this pre-ovulatory follicle? This would the key indicator for me for this scenario.
hCG does not always work... what dose was used? has hCG possibly been over-used in this mare and does she have antibodies present? Still, it doesn't always work - talk to your vet about GnRH for next time, and make sure you are paying attention to the shape of the pre-ovulatory follicle and not just size!
When we AI'd our maiden mare, she wasn't catching either even though she had large folicles ready to go... She didn't drop them. Sorry if I'm repeating what has already been said but I'm not familiar with the acronyms "HCG" or "GnRH". The second year we attempted AI, we inseminated one day and then used an "ovuplant" to try to force ovulation. We then inseminated the second day and she caught! Good Luck! I know it can be tricky.....
Just wanted to add to Dale's post. Obviously it is very important how much edema the mare has. Even if she has a 40 mm follicle but only number 2 edema (out of 5) - most likely you wouldn't order semen. (Unless the mare usually moves really fast.)
Heather it's funny were going through the exact same thing.
Palpated mare on MON Monday ordered semen Inseminated on Tues Wednesday she didn't ovulate. Thursday she ovulated Appoinment with vet for next week to see if shes pregnant. (giving we did all this last week)
Hey all, Things are looking a bit more up. Mare ovulated. CL present. With all hope, the AI will be good. Mare will be re ultrasounded in 14 days.
Dale, Would never blame the stallion/shipper. They have been quite accomadating and very helpful in this situation. This stallions conception rates are 95% for AI the past 4 years, so feel if there are mistakes....it probably would not be on their end. Prior year, this mare was HCG'd on a very soft 37 mm follicle and bred the following day. Conceived first insemination. This year, we've been monitoring her pretty closely. she has has multiple follicles, but had the predominate follicle progressing based on continued ultrasounds. I don't make it a habit to HCG unless SURE we are going to ship when the mare is likely to be ready (as if this isn't already a crap shoot). This is her first breeding of the season, as she had a foal in Jan...and I opted to hold off so we could get a later foal next year. For this mare, a 40mm follicle is as big as she's ever had....without doing counter-to-counter..vet was concerned about giving HCG without semen on board. With this mares prior repro history, low SEE score (1), with a 40 mm follicle....ovulation appeared fairly imminent. She just held on a little longer than expected....but that happens.
Based on the stallion/shippers recommendations and continued discussions with the vet, they seem to think that the timing is still pretty good.
I apologize if I could not provide more specific information. Due to time constraints, I've been absent for all but 2 ultrasounds, so have missed the specific's in between...and get the high points delivered to me by phone from the vet after exam.
Heather: No point in commenting - your ultrasound will say it all...
Re: Lindros' post: Even if she has a 40 mm follicle but only number 2 edema (out of 5) - most likely you wouldn't order semen
Not necessarily true... the edema peaks about 36 hours prior to ovulation, so by the time you have a 40 mm follicle you may well be close to ovulation and expecting to see a reduced edema level. In fact, I would expect to see decreasing edema in conjunction with a 40 mm follicle...
Jos: I agree with you. However, doesn't the follicle look different when the mare is getting ready to ovulate? Thick walled and starting to look like a CH. Of course the teasing history of the mare has to be taken into consideration as well. I was refering to a mare who just started coming in and usually gets good edema (sorry should have been more clear... ).
"doesn't the follicle look different when the mare is getting ready to ovulate? Thick walled and starting to look like a CH."
There will be a change in shape and thickening of the follicular wall visible per ultrasound in about 85% of pre-ovulatory follicles, but not all. So no, it won't necessarily look different.
Note that a "CH" is a corpus haemorrhagicum, a structure that may appear following ovulation, but not all mares will develop a CH. It is not the same as a "CL" (Corpus Luteum) which is the structure that forms following ovulation that secretes the hormone progesterone. The CH is formed when blood seeps into the evacuated space left behind following ovulation of the follicle, and some mares skip that step and go straight to developing luteal tissue. In any event, if a CH is visible, it will be present after ovulation, not before, and cannot therefore be used as an indicator of impending ovulation.
Congratulations Heather!! Oh how I wish I could start this all again for next year once I have this foal on the ground. I couldnt do it to my poor girl though with her dodgy feet!! Never mind - Im sure the first one will keep me plenty busy. Good luck Heather, pleased for you!
The edema you speak of, where and when is it present, I haven't heard my vet refer to it ever?
My mare was at a 15 this past Monday the 10th then Wednesday she was still at a 15, then friday she jumped to a 30 with a closed cervix. I am getting nervous about the weekend since we are doing AI with her. Any thoughts on her timing?
"Counter to counter" is a mode of transportation wherein the semen is transported via commercial airline cargo. Note that in the US it is now necessary for the shipper to have "verified known shipper status" as a security measure.
Edema is present at certain times in the uterus and seen via ultrasound. The edema is present as a result of steroid secretion - specifically estrogen - by the follicle. It is an excellent indication of estrus ("heat"), and should be observed during the breeding cycle. Mares are unique in that they can produce - and ovulate - follicles when not is estrus, so it is essential that it is confirmed that the mare is in estrus prior to breeding (a variety of problems may result if she is not). Follicular diameter or indication of impending ovulation alone is therefore not a sufficient indicator of time to breed, and edema is generally looked for.
Your mare is following a normal progression. One would expect to see smaller follicles (e.g. 15mm) during diestrus (the time between heats), one (or sometimes more) of which will ultimately become the dominant follicle and go on to ovulate (probably). The enlargement of the single follicle to a 30 mm follicle is probably an indication of this going on - as long as it is not one of those mid-cycle follicles. Note that the cervix relaxes as a result of the reduction in the circulating progesterone levels in the mare when she is in estrus. Some mares however (especially older maiden mares) may not have cervixes that relax, and that can be a problem that needs dealing with to assist in establishment of pregnancy.
How do you deal with cervixes that will not relax? I do have an older mare (13) who was unsuccessfully bred by AI 5 times last year. She did test hypothyroid in December so we have her on Thyro-L, but I am wondering if a tight cervix or clearance might not be an issue as well. Hummm...
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