Today's webinar is called Stallion Semen Collection and Artificial insemination. Obviously, that is a broad topic, and in the time constraints, there's gonna be certain aspects of it that we can't cover in a greater amount of detail. But, the learning objectives that are available if you want to have a look, and the MCQ, the multiple choice questions, should all be able to be answered by somebody who listens to this webinar.
What we'll start off with, I think, is the actual process of semen collection from the stallion. Now, many colleagues get, a little, I don't know whether nervous is a word, but are a little bit anxious when they have to go and collect semen from a stallion, and on one hand I can see why that is the case, but on the other with a a few of the techniques and and some of the things I've learned over the years, which we'll talk about in this webinar, I hope it'll make you more relaxed about the procedure, and able to do a better job. Now, of course, the set up when we're collecting semen is important and you know, you may not always have a great control over that, but where, where you are able to, obviously this is a picture of a specialist semen collection.
Centre, so I'm not, not suggesting all veterinary practises or breeders are gonna be able to have a semen collection area on this level, but nonetheless, it's useful to highlight, the, the best features. And what we have to have top of the list there is safety, not only for the stallion, of course, but also for the personnel involved. There's no way of getting away from it that it is a potentially risky procedure collecting semen from a stallion.
There have been injuries documented and it's important to maximise safety aspects. So you can see here, we've got a large area, so people can move away if required. The stallion's got plenty of room.
All the personnel in the room, aren't on top of each other, so safety for stallion and personnel wants to be reasonably close to the laboratory where the sample's gonna be taken to process the semen, you don't want to have to start going half a mile across a windy, dusty, cold, . Yard anyway, it wants to be as close as as practically possible to the semen processing laboratory. It doesn't want to be dusty in, in, in many situations over the years I've been asked to try and collect semen in an outdoor arena, and whilst that's obviously possible, you can imagine there's a much greater tendency for dust to be set up in that procedure, which obviously can then potentially contaminate the sample and so on and so forth.
We'll return to this point several times during the webinar, but a dummy mare is, is, is, is strongly preferable to using a live mare to have the stallion jump on to allow the semen sample to be collected, and we'll go through why that is when we look at the dummy mare, in particular. The flooring, as you might guess, wants to be non-slip and level, that's common sense really. And you can see in the front there to the left of the dummy mare on on on the screen as I see it anyway.
There's a stable for a teaser mare. What is that? Well, that's a mare in Eres which some stallions need before they'll jump up onto the dummy mare and work successfully.
Other stallions, you don't need to, and over the years I've worked with some which you had to definitely had a teaser mare. Others you could collect semen every day, spring, summer, winter, and no teaser mare was required. A spacious area we've touched on from a safety point of view, and it wants to be readily able to be washed and cleaned down, in between collections, in between stallions with hygiene as ever in the whole process of AI and semen collection, maximised.
Now, stallions do need to be handled properly in order to have a safe collection. Everybody may have a different preference as to whether they like a head collar on the stallion, a bit on the stallion, a chiffney, whatever, and, you know, I'm not saying one thing is, is right or wrong, you've got to learn what works best for you. I like a a lead rope with a decent length on it, and I'm.
Personally quite keen on having a a bridle on the stallion. I think in this picture we're actually using a chiffney, so all things or or several different things are possible and find what works best for, you as the as the collector er and or the stallion. Now, just a little, we haven't, we're not going to in this webin I'll have these are these voting things where you can vote on little handheld boxes during the lecture or webinar with your decision.
But I've left this in, even though we're not going to be using them today, just because they're useful and, and you can have a think about them before you, . Move the webinar on if you're watching it prerecorded as most of you are. You can pause if you want while you think of the answer.
This is a relatively straightforward one. Should the stallion handler and the semen collector be on the same side or different sides. Now, the last time wherever I was, I can't recollect, I polled this question.
90% of colleagues said the same side. 10% went for different sides, and. As the 90% were correct in their approach, it is, of course, the same side.
The semen collector and the stallion handler should be on the same side of the dummy mare. Now, stallions need more or less training to use a dummy mare. There is a technique for training a stallion onto a dummy mare.
It's not the subject of this webinar, it's, it could be one for another day, . It generally most stallins it's quite easy to train them, to, to, to allow a semen sample to be collected using a dummy mare. Now, what do I mean by the stallion handler and must look after the collector?
Well, the collector of the semen is concentrating on just that, collecting the semen, and it's the job of the stallion handler to take in the surroundings, what's happening with the stallion, what the stallions. Maybe facial impressions are, what it's looking like he's going to do. And you can see there is a a a front leg of the stallion quite near the arm, the advanced arm of the semen collector, and it isn't visible in this photo cos it's obscured by the back.
Of the semen collector who's rather tall, they are actually cupping, holding the front foot to try and stop that contacting inadvertently, the arm of the semen collector, the one injury, I, I've had collecting semen was actually some damage to my, my arm, where the, the, the foot front foot of the stallion came back onto me as I was collecting the semen sample. So I, I'm always keen that we have a good stallion handler who hangs on, or shields that, foot hoof to protect the forearm of the semen collector. As with most things, if we can get the stallion into a set routine when he's going to collect semen, that I find er to be advantageous.
If we have a look at a video clip of collection on a dummy mare, that shows the process in action. Here we've got quite a big stallion, gonna go up, he's well trained, going onto the Dummy mare, and you can just see, I think in this picture, the stallion handler is watching that front leg of the stallion to make sure it doesn't come back onto the forearm of the person collecting the semen. And then you can just see off to the left is a teaser mare with this, the stallion which we tended to have in as a routine.
So there you have a little video clip of stallion semen collection. Once he's ejaculated, come backwards as a collector with the AV then remove it. So handers and collectors on the same side, let the collector know when the stallion is going to mount.
And, and that's emphasising that the stallion handler has a very dynamic role in this, and it's important at the end of collection back the stallion away from the dummy mare. Now this is quite a nice little video clip I like to show, it just shows the importance of the stallion handler watching that front leg. We've slowed it down now.
Look at that potential for that front leg, not the stallion being. Nasty or in any way vicious, but the potential for injury there in this process. In this clip as well, we have stumbled the, the other side of the dummy mare, just to try and keep the stallion straight.
Here you can see that the stallion has got a little bit on an angle to the dummy mare, and that makes the process of semen collection a little bit tricky, so it's good to have the stallion. Over, on, on the, on really sort of the other side, certainly tighter in, to the, dummy mare and the head, I would have on the left hand side. Now, my, my preferred material for the dummy mare is a sort of industrial sort of robust plastic, because that is very easily cleaned.
There is a potential for the stallion to rub his knees on the dummy, May, if you're making repeated collections on a daily basis over several weeks. So what we can do is sometimes quite often we'll bandage the front legs of the stallion to cover the knees to make sure there's no abrasion. Very, very important, as we've already said, to clean down not only the floor and surrounding collection area, but particularly.
The dummy mare itself in between every single semen collection that tries to minimise the risk of any cross-contamination and therefore spreading disease. Now, I, I, not so often nowadays because I would say that 99% of times when I collect a semen sample, I am doing that using a tummy mare, but just occasionally you might be put in a situation where you've got to use a live mare. I don't like that situation because it it it it adds another factor of risk in terms of safety and potentially disease if the stallion, you know, misses the AV and goes on to sort of almost cover the mare, you know, so it's important these mares are health screened, but it's a, it's an additional area of risk in terms of the mare kicking out.
And injuring either the collectors, or the handlers, or the, or the stallion himself, and, and it may, the may may not be in good estress, so, you know, that makes the whole thing even worse. So try and avoid having to collect a sample using a live mare, if at all possible. Again, obviously, if you are forced with having to do that, the same things apply as before, and it's, it's, it's even more important to make sure that you back the stallion away from the mare and watch out for the mare kicking out as you're doing so.
As we've said, using a dummy mare is infinitely preferable, less risk of injury, hygiene's easier, interestingly, I've, I've put in this slide, I, I was, had a wonderful time working for a couple of years at the university in Utrecht in the Netherlands, and we collected many, many hundreds of semen samples from a wide, a range of stallions there, so different height, that's why it was nice to have a hydraulic, dummy. But I don't like the cover, I don't like that leather cover on the one sense it's, it, it's good, and it's durable and . Quite a non abrasive surface for the stallion to jump on, but it's not, it's not as easy to keep clean as the sort of thick plasticy, covered dummies which, which I tend to prefer nowadays.
Again, you can see in front, you've got a a a cage, a stable, whatever you want to call it, with lots of openings in it where a teaser mare can go. It's much preferable if the stallion's going to need. A teaser mayor, to encourage him to mount the dummy mare, that rather than just having that mare in Eastres, you know, in the room, as it were, in the collection area, the mayor is safely out of the way in a contained stable.
Before every collection, we wash the penis of the stallion down, we do not, we do not use disinfectants, I think we all know that now. We just use water and disposable, paper and dry the penis thoroughly. It's important not only can there be, smegma to remove, but if the stallion's bedded on shavings as he's here, you know, shavings can coat, the penis of the stallion, and obviously they could be abrasive if we did not remove them prior to collecting semen from the stallion.
Both stallions, you know, if you haven't done this before, you may think they won't tolerate it very well. Actually, we find they do. They tolerate this procedure very, very well.
Here we're using a bucket which you've actually, you can't I don't know whether you can just about make it out of the video. We've put a plastic bag. Into the bucket.
That's, we use a different plastic bag in between each collection, and it just makes sure if there are little cuts and nicks in the, we're just cleaning the, around the urethra there, that just sometimes they will show a little bit of . Little bit of agitation at that part, as I say, we use a bucket with, with a plastic sort of liner which we use new each time, so again, all with the aim of avoiding, contamination. Various types of artificial vaginas, they are all essentially.
A similar device, I mean they're a insulated double line water jacket in which the penis of the stallion is placed, he'll ejaculate and you can collect the sample. My preference is for the Missouri AV and here I've shown the three different sizes, and that in itself I think is a good advantage of the Missouri AV. And there's another big, the fact you can get different sizes, and there's another advantage of it, which I'll touch on when I talk about the temperature of water, which is best to to to to get a, A collection relatively straightforwardly, the, the optimum way to collect the semen sample.
What is the temperature of of that AV? Excuse me. So, what should the luminal temperature of the artificial vagina be?
Now there's a range. Now it's always quite hard with a range like this because there probably isn't a set answer, but I, I'm going on what typically we would have. And the answer is typically, I, I, I aim for a luminal temperature of 45 degrees C.
Now. You can see here the vast majority of people thought 40 degrees. Well, I, I, I think that's a little bit low, to be honest.
So as I say, my rule of thumb typically, is to have a luminal temperature. Now that's not the temperature of the water, that's the luminal temperature in the interior of the artificial vagina. Obviously the water temperature, you can see here, one of our technicians is filling.
The AV. Obviously the temperature of the water, it depends on what the ambient temperature is and the temperature of the AV is. I mean, if, if the AV is very cold and it's very cold outside, you may be filling this with water at 55, 60, you know, gosh, possibly even 65 degrees.
Warmer conditions, if the AV's been pre-warmed in an oven, you're going to require, water maybe just only above the 45 degrees. So I aim for a luminal temperature of 45 degrees. A range though, you can do, I mean, 43 to 46, it's a little bit artificial to put a value of 45 on it.
It doesn't matter if it's 44, it doesn't matter if it's 46. Now, if, if, if, in certain situations, I'll use a luminal temperature, you know, considerably higher than that. That's a pretty high temperature 50 degrees.
Why might I do that? Well, I'll tell you why I try a luminal temperature of 50 degrees. It's when I'm having a little bit of difficulty collecting a a semen sample.
What I found is if a stallion's reluctant to give a semen sample, increasing the luminal temperature of the AV seems to help. Now, as I say, and as you may think 50 degrees is pretty warm there, so it's important that the semen, when ejaculated, doesn't come into contact with the liner at that temperature. So that's why I like these Missouri AVs because I can visualise the end of the penis of the stallion, and I can use a size of AV such that the the end of the penis and it it is at the end of the leather jacket, so it's out with.
The, the, the 50 degrees as it were, and he ejaculates into the end, you know, that last, I don't know if that's coming out on the screen then Arrow, but this last third of the artificial vagina away from being at 50 degrees and then runs into the collection bottle, which of course you have attached there. So that's, that's a little tip if you're having trouble collecting semen from a stallion. Try increasing the temperature.
Now, it's important to philtre the semen sample because there's not only the the the chance of gel, most stins will have a more or less gel fraction in the sample, and the gel fraction contains very little sperm, so we want to philtre it really out of the way. It makes handling of the sample difficult. Now, in addition to that, there is obviously no matter how well we've cleaned the.
Pennis of the stallion and no matter how much we have a dust-free environment, there is a possibility for contamination of the sample. So whichever way we look at it, it is important, to, to, to separate the sperm rich fraction of semen from the gel. Now, the majority of people in my experience, seem to like an inline philtre.
And there's a, there's an example there where the, the, the philtre is, just before the, collecting receptacle. And that's fine, absolutely fine. Now, probably because I spent a lot of time in the Netherlands collecting an awful lot of semen, and the system there was, we filtered it after collection.
Everything's up at room temperature, actually it's, it's not room temperature, in fact, it's, it's warmed, it's at 37, it's a body temperature, . So we've got some a a a a a measuring cylinder you can see in the middle picture there and a funnel with some clean gauze on. And I'm going to philtre it, that's, that's one of the technicians there.
Andries he's gonna philtre that after collection. So some people have an inline philtre, some people philtre out. Collection.
Either way, it is important to separate this, you know, very thick, tenacious, sperm free, almost gel fraction from the semen sample. Otherwise it's going to be very difficult for you to carry out meaningful analysis and package it properly. I mean, these two examples that they're a little bit amusing in a way, any port in a storm, but they're making quite a serious point that it is important if you're gonna be asked to go and collect semen at a a a client's premises where you perhaps haven't done it before, you don't know that well, I've had to do that.
On many occasions over the years, either as a referral or because the, the, the local vets didn't want to, collect the semen or didn't have the equipment, and, you know, there was not a suitable, safe, method of collecting the semen in terms of a, You know, even a mare in Good Eastress, let alone a dummy mare, and if that is not the case, well, it just is not going to happen. It doesn't matter if you've driven 50 miles, 500 miles. If there's not a mare in heat or the stallion train to a dummy mare, well, you are going to struggle to get a semen sample, so.
If ever you're faced with having to go collect a sample, a decline you're not familiar with, very, very, very important to make absolutely certain that there is going to be a suitable mare in heat or much preferable, the stallion you're collecting from is trained to a dummy mare. Why might a collection fail? Well, as we've said, the AV, the artificial vagina, is not hot enough.
Of course, you can have the, contra of that. The AV is too hot, too much water, not enough water. These are all things you'll find different stallions have different.
Just occasionally a stallion doesn't like a particular type of artificial vagina. Some stallions like more or less lubricant. Some stallions we generally try and collect with a disposable liner because it helps keep everything clean.
Some stallions, very, very few, but some just do not like that disposable liner. If you're having a stallion where it's taking some time to collect the sample and pre-ejaculatory fluid can build up, that can be quite toxic to the semen sample when finally ejaculated, not only per se, but because it's probably rather cold if it's taking several minutes before the stallion actually ejaculates. Not teased enough or just poor libido.
So a a host of reasons why a collection may fail, some related to the collection process, others related to fertility issues with the stallion, which are obviously the subject of a. Web in after another day. Every single semen sample must have good records.
At the very least, the stallard name, the date and time of collection, and accurate measurement of volume, the density or concentration, same thing of the sample. Not only motility, the one. Moving, but, but we count progressive motility, ones that move with purpose across the field of view.
And we make an estimation of the progressive motility. This sample here I would put it a right, it's a good semen sample is that, that's about as good as a semen sample as you see. I, I would call that 55 to 60% progressive motility.
It's a subjective assessment. Only, of course, I'll talk about how we can do objective assessments in the coming slides. So I generally evaluate motility first.
You can see here that we need a decent quality phase contrast microscope, importantly, with a warming table. You can see that the warming table is, is, is taken up to 38 degrees, periodically, I will. Check that.
I won't just accept that the heater, because it says 38, is producing 38 degrees. Periodically we should check that. I have known where it's been overheating or under heating.
Despite saying 38 and on the right hand side you can see I've got my cover slips and slides also on a warmed bench. So, a a a a reasonable quality, extend it first, I'll tell you what actually, I do always look at A raw sample. A drop of a raw sample just to to to really check we've got some nice movement, not making any, objective assessment, but just making a subjective assessment that yes, this stallion semen is moving.
Now I'll tell you why I do that. We once had a problem with, A sort of fault with the extender which was highly toxic to sperm when we added it, and if you simply, as, as is best when making an accurate motility assessment, you extend the semen sample, but if the extender in the very, very unusually, I've I've only ever happened once, but I've, I've never forgotten it, . If the extender happens to kill the semen sample, well, you're going to look at the sum and think, oh well, this stallion's got a problem, er all all his sperm er er are dead.
And in fact it isn't the fault of the stallion, it's the fault of the extender. So ever since then, I will just have a very, very quick look at a non-extended sample, not to make a a a motility assessment, but to just check, well, yes, we've got movement, we've got live sperm here. To make the, although I accept it is a subjective assessment, but nonetheless, I think in, in, you know, if, if ever we do a practical course and you can look at and we go through semen assessment, I, I'm pretty confident over the years I've been able to teach people to evaluate semen, albeit subjectively, with a plus minus 5% accuracy.
So we extend it first with a semen extender to a concentration of around about 50 million spermatozoe per mL. That allows you to evaluate the sample, more accurately than a raw sample. You put a small drop again, unfortunately too many colleagues will use, you know, maybe a 5 mil syringe and try and put a drop off the end of that, well, You know, it just goes swimming all over the microscope slide.
Please don't do that. Use a micropipette and put something like 1015 microliters only on the microscope slide, then put the cover slip on. Assess progressive motility, that isn't just sperm going round and round in a circle, it's sperm moving progressively across the screen in at least 5 different places.
It's also important to make a judgement about the longevity of spermatozoal motility, particularly in an artificial insemination programme where semen's going to be shipped overnight or frozen, we want to just get a handle on how long that sperm remains motile. So important, use one of these micropipettes or at least a disposable micropipette. We don't really want to be putting a drop much over 10 or 15 microliters on that microscope slide.
And, and again, when assessing motility, reasonable quality microscope and, Everything has to be a heated stage. You can't assess it on a cold microscope slide on an ordinary microscope with no heating stage. So, that's motility.
Next we we'd look at concentration and volume. Now. Confusingly, you'll see concentration and density written sometimes.
It doesn't matter which one you pick, but they are the same. And concentration, sperm numbers, sperm concentration are typically between 150 and 250 million times 106 million sperm azoa per millilitre. That is, is of the order.
Now It's very important if we to work in the end we want to work out the total number of motile sperm. Now to measure that, we, we actually need, or, or to get that figure, we need 3 measurements, don't we? We need the motil progressive motility, which we talked about the slides before.
We need to know the concentration, but we also need an accurate handle on ejaculate volume. Now, I've left this semen sample in the collecting receptacle we often use, a a a baby bottle, but we do not go on those measurements written on the side of that bottle. They're very, much a, and I wouldn't say an estimate, but they, they, they, they're not with any accuracy.
And it and it is very important to get an accurate assessment of volume. So we use a clean measuring cylinder. So you do need an accurate measuring device.
To measure the volume. Now to measure the concentration, I mean, one of the most accurate ways, if not the most accurate, is very laborious. It's using the blood cell counting chambers, so that's why it's called a hemocytometer.
And for those of you who've done that, they're made up of these little squares and you put the semen sample. Excuse me, you put the semen sample onto the chamber, . And you count the sperm.
Now, if we're doing a practical class, I often ask the colleagues performing the semen assessment, are you going to measure concentration on a live sample or a dead sample? Well, believe me, if you've ever looked down a microscope at these little tiny cross hatch squared areas, it's hard enough to count the sperm when they're dead and not moving. It just simply would be impossible to count them moving.
So when one is making an assessment or a measurement of sperm concentration, it is done on a dead semen sample when using a hemocytometer counting chamber. Doesn't matter when you think a spectra photomic because they just measure. You know, amount of light passing through.
Typically, normal standings produced between 100 million and 800 million spermatozoa per mL. But as I, I, I think I alluded to before, total sperm output is more important. Over the last few years, many breeders in our practise have begun using this machine.
It, it, it, it is relatively expensive, around about 2000 pounds, but compared to The original CASA computer assisted semen analyzer, which cost many thousands of pounds, it's, it's relatively good value and it does provide a more objective assessment, not only. Of motility, but also concentration. So, if you're performing any reasonable number of, of, of semen assessments, then I, I would encourage you to get one of these, and, and in the UK they're available from Stallion AI services if you're watching or listening to the webinar.
Somewhere else in the world, I'm sure, as far as I know, most countries have these available. Now, when we are inseminating a man, we use, or we need to be familiar with a figure called the insemination dose. We not only need to know what that figure is numerically, we need to know what it is as a concept, and I'll tell you what it is as a concept.
Back along in the late 70s, early 80s, 2 very, very large field studies were done where large numbers of mares were inseminated with ever increasing numbers of sperm. Say 100 million progressively motile sperm, 200, 400, 600, a billion, 2 billion, and so on. And what they, what, what colleagues found, which is very interesting.
Was that above 500 million normal progressively motile sperm. There wasn't an increase in pregnancy rate by putting more sperm in. So if you will, that is a sort of .
You know, number of sperm above which you won't get any more mares in full, . Now of course, even the best package, chilled semen or frozen semen is, there is going to be some drop off in sperm numbers, either with overnight shipping or freezing. That stands to reason.
So the industry recommendation is that for semen that is going to be transported. Or frozen rather than use fresh within an hour or so we use double that number now we would hope. That less sperm would die than than are required for double, but to to err on the side of safety, I think that is a good aim to do.
Now, double 500 million is 1000 million, which in, in, is a billion, at least in the UK anyway. Now, of course, there has been some work recently that if rather than we'll we'll we'll refresh you on this, but we, we normally aim to put the semen of the of of the inseminate, you know, halfway along the uterine body of the mare. But these days we've we've looked at using a a a special sort of catheter, directing the the the inseminate right to the tip of the uterine horn.
And it stands to reason that if we did that, we may need less sperm numbers. And in conjunction with that, there's been improvements in seamen extenders, and there was a a nice paper by Steve Brinsko and his colleagues, from Texas A&M looking at this figure of, 300 to 500 million progressively motile sperm as the insemination dose and suggesting that a lower figure may in fact be the number above which more mares won't go in full. So I leave that with you, as a practise we still would aim to ship, Semen being used either in a chilled semen insemination programme or a frozen semen insemination programme as 500 million times 2, which we would say is a billion, progressively motile sperm.
But it may be we can use a, we could use a little bit less than that if there was some particular need to. So that really has dealt with the semen collection process, semen evaluation process and dealing with the sample for shipping out to a mare. Obviously we, we're not gonna deal with freezing the semen sample in detail, or haven't done, and we're now moving to how we maxim, what do we do at the mere end of things once we've got this semen sample.
Well, let's just be sure we are all happy with what we're talking about, . The types of semen, there are obviously fresh semen, we use freshly collected within half an hour, an hour, and the other type of liquid semen is chilled, and if ever you chill semen down to 4 degrees, you extend it. On the right, the, the historically best container for shipping chilled semen as an e.
Still really the Rolls-Royce if we're using air, travel, over long distances. If the distances involved in shipping it are relatively short, the polystyrene boxes are shown on the left with a couple of ice packs have become, much more common to see than the traditional equittainer. The other type of semen, of course, is frozen semen, which in the horse is frozen in half mal straws.
The dose really can be between 1 and 10 straws. You don't often see 10 straws now. I think most breeders aim to have stallions frozen, .
In 4 straws or less, and that makes the handling of it, and the insemination process a little bit easier, generally, but it's always worth checking, we thought 37 degrees for 30 seconds and the sealing method for the half mil straw, overwhelmingly now a a a crimped approach is used with a little wad of packing below, the crimping. You don't see much powder sealing or or thankfully, the old steel ball, which, which had a terrible tendency of popping out at thawing and, really were quite dangerous apart from rendering the semen sample. Rather useless.
So, the timing of it, well, we have to accurately predict ovulation in the mayor. Now of course that is a subject in itself and in the past I have presented a webinar on prediction of ovulation in the mare, so, if those of you who wished you could go back and check that out. In that we go into great detail about what we clearly haven't the time to go into great detail here, but nonetheless, I felt it rounded off, it ended, this session on semen, collection and evaluation, talking about the actual insemination process and its timing.
So, . I think it's it it it seems logical to finish the webinar with some information on the best way to inseminate the mayor to achieve a a pregnancy. So we've got to accurately predict ovulation and, and, and there the 4 means we can do that, teasing isn't particularly accurate, follicle and cervix evaluation, the uterine edoema pan, and the time after ovulation induction agents, that's what we use.
Now these are the mere records which we use in. Our practise, and we have a silhouette diagram of the left and right ovary, and we always detect the presence of the corpus luteum and we record any follicle over what size. Well, there isn't really a right or wrong to this, so I, I, I, I, I set up a A slide which I put to the, I've put to audiences or colleagues listening to one of my lectures over the years posing this very question above what size should follicle data first be recorded in the mire?
1520, 25, 30, 35, 40 now. I don't think there's really a right or wrong, although, I, I think if we only began at 35 millimetres or 40 millimetres, we would be taking a big risk, and this is based on a typical thoroughbred warm-blood mare of 450 to 600 kg. Now, wherever I polled this question last look, you can see around about almost half of the colleagues listening to the lecture or webinar went for 25 millimetres and.
I don't know whether by coincidence, but, but possibly because I'd worked that out as well. That is in fact what we do in our practise. Any follicle over 25 millimetres, we make a note of.
The reason being that follicles are typically of the order of 35, 38, 40, 42 millimetres when they ovulate. So if we recorded follicles much below 25, well, they may still be many, many days before they're, well, not many, but several days before they're coming on to ovulate. If we don't begin to record them, till they're over 35 millimetres, well, that's, that's too close, really.
To them being about to ovulate. I just want to make this point because it's not always comes, it doesn't in books and it may be quite hard to explain in a a book or a or a written word, so I always try and make this point when I'm delivering a lecture. Yes, follicle diameter is a useful tool, but.
Only whilst the follicle retains its spherical shape. Once the follicle is 35 millimetres plus and is softening, well, it's changing shape and I'm less concerned with the absolute size measurements, more some of the other ultrasonographic changes which I will just touch on in the next couple of slides. So follicle diameter, yes, for sure, it's a useful tool.
But only whilst the follicle retains its spherical shape. When we get a follicle close to ovulation, typically over 35 millimetres, well, I think we're better to go on other things rather than becoming obsessed with wondering whether it's gone from 35 to 38 millimetres. Look for an increased ecogenicity of the follicle war.
Look for these. Small echogenic particles generally in the ventral portion only of the follicular fluid. And then of course we all know that the other technique we use to predict ovulation in the mirror is endometrial edoema.
I want to refer you to a couple of excellent, quite old now, but that doesn't matter, they're still perfectly valid. A couple of excellent presentations by a very good friend of mine, Juan Samper, in the '97 AEP ultrasonographic appearance and the pattern of edoema to time of ovulation in mares, and then again. 10 years later, WAM presented it, and, and that paper more explains that in abnormal measures, may say prone to fluid retention or prone to, aspirating air, well, endometrial edoema patterns aren't as .
Always comparable with how they are normal mares, in particular what you find is that mares prone to uterine fluid accumulate accumulation, sorry, can ovulate. Still with a very marked edoema pattern and that, I, I, I, these are both available online, and I would strongly encourage you to go and read both those papers. I'm firmly of the opinion that endometrial edoema is a massively important tool for us in our armoury of accurately predicting ovulation.
So it's important that you grade the edoema pattern, now you can grade it. Slight non mild, moderate, you can grade it by name and grade it by number, you can grade it from 0 to 10, you can grade it from 0 to whatever. We, in our practise grade it from 1 to.
1 to 4, I, I don't really see much point in going, using any more parameters than that. So that is a score 1, score 2, score 3, and there's a score 4, which is almost an excessive amount of edoema, in fact, you can see a degree of intraluminal fluid there, and we all know that mare's prone to fluid accumulation, are prone to persistent post-breeding. Endometritus and again there's a, there's a webinar on how to deal with those sort of mares.
In summary with you trying edoema, when we've got a grade 3, when we've got a maximal edoema pack. We know that edoema scores tend to decrease in the normal mare 24 to 36 hours prior to ovulation, and that's generally the time we want to be giving our ovulatory inductory agent, be it corolon, human chorionic and adotrophin, or Deslorein injection or implant. And, and again, if you, if you go back to the talk on .
O ovulation prediction as a whole topic, we'll talk in some detail about those ovulator inductory agents, but we use them extensively in our practise, either corelo or if we need to have a more accurate control on the timing of ovulation, we'll use Deslorein. Of your plants Now, why is ovulation prediction important? Well, of course, sperm does not live forever in the mare's reproductive tract, .
It depends on the stallion, some stallion sperm lives longer than others, and it depends on what you've done with the sperm. If you've frozen it, you know, no matter how careful you are, it's damaged to an extent, it's not gonna live as long, obviously, in the mare's reproductive tract as fresh semen. Now, pretty soon after insemination, the sperm go up, leave the uterus, in fact, and go up into the mare's oviduct here you can see a picture of a mare's oviduct, and that's where most of the sperm will be following insemination.
And that process occurs pretty rapidly. This slide on the right is a scanning electron micrograph of a mare's oviduct. Just 6 hours after insemination, you can see all the sperm, or pretty without doubt the sperm, they're going to fertilise the oy.
They are up in that oviduct. They're not in the uterus anymore. It it's always difficult to, to give precise figures, but we have to, to have something to work with.
I mean, fresh semen, we think lives, oh, at least 2 to 3 days, probably 4 or 5 days from many stallions. Fresh semen will live that long after natural covering. Chilled semen, generally 12 to 36 hours, from insemination, because, you know, that semen can often be, 18 hours old, by the time you inseminate the mare, and, and it's not really, it's difficult to expect it to live much beyond another 18 to 24 hours.
Some can do, but as a rule of thumb, if you inseminate a mare with semen that has been shipped overnight. I would like to see that mare ovulate by the following day when we check to first thing in the morning at 8 a.m.
Frozen semen less obviously than that. Some frozen semen may not even live 6 hours. We would like to think these days with better freezing techniques and so on and so forth, that is not the case, and we, we, we would expect frozen semen to live at least 12 to 24 hours from insemination, so we have to make sure that ovulation occurs within, ideally within 12 hours of inseminating the frozen semen.
But do bear in mind that semen from subfertile stallions may have have a considerably shorter lifespan than that. I, I'm sure you all know that the conventional place for insemination is halfway along the uterine body. It's very important to have the mare in stocks, have the mares vulva hygienic prepared not with disinfectant again, just as we do not use disinfectant on the peni.
We do not disinfectant to prepare the vulva of the mare prior to insemination. Tail bandage, nice disposable glove there, and, and. Likegenic.
Worried about getting kicked. Forward technique to inseminate a mare, but nonetheless, it must be done properly. Now, that really brings us to the end of the webinar, semen collection and artificial insemination.
Obviously we haven't been able to cover some areas in a great bit of detail. I'd put a little bit of plug to some of these texts. Current therapy and equal and reproduction is, if I say so myself, a useful book for anyone involved in equine reproduction there's, it's a multi-author book, although the three of us edited, myself and my two good friends, Juan Samper and Angus McKinnon, we we use many of the of the world's best equine.
Reproductive clinicians to produce the individual chapters. So, many of the topics we've talked about here will be covered in more detail in those textbooks. So that brings us to the end.
I hope you've found that worthwhile, and thank you very much for listening.
