My stallion has a large book of mares this year. By large I mean 75+. Besides our own mares, we are exclusively shipping cooled transported semen to our clients. We intend to try and freeze some but at the moment he is being used at capacity! I only ship at least 1 billion progressively motile sperm as is the norm in our breed.(or so I've been told!) Some days his concentration is low and in order to give 1 billion P.M. I am sending approx. 75 mL. On other days his concentrations are OK and I ship 45 or 50 mL. Is there any way to increase his concentrations medically or nutritionally? I have heard that I may have to fractionate(sp?) or centrifuge his semen and I am not looking forward to buying a centrifuge if at all possible. His libido is great, his health is great for an older stallion and he has been a joy to be around in all respects.
Jos Posted From: 137.186.22.117
Posted on Wednesday, May 05, 2004 - 11:11 am:
There are no drug or nutrients that have been shown to improve sperm output.
Try not teasing him as much. The more you tease, the more volume you will get, but you do not get more sperm - hence the concentration drops when the volume increases.
Fractionation does not require a centrifuge - just quick reflexes! Catch the first three ejaculatory spurts and discard the rest. The first three spurts will contain the majority of the sperm-rich fraction of the ejaculate, but little to none of the secondary sex gland secretions (seminal plasma etc.), so total volume will be significantly reduced (and concentration therefore raised).
Anonymous Posted From: 65.93.148.210
Posted on Saturday, May 08, 2004 - 04:46 pm:
If we tease him less, he performs as well on the phantom, and he requires two jumps usually. When he requires two jumps, I change the filters & bottle after the first mount and the second jump is much higher in concentration I am supposing due to the fact that some of the pre-ejaculate has been discarded.
Do you have any other options for me to try with this stallion? I would surely appreciate any tips you may have with your significant experience. Thanks.
My confusion lies in the fact that we analyzed this stallion pre-breeding season, determined the concentrations and extender ratios, yet his concentrations have dropped almost in half in three months. They are maintaining at a minimally acceptable range for his book of mares but I am unable to extend the semen in the correct ratio for extender:semen. I am keeping my fingers crossed that the mares on his "worse" days catch. I would not be so worried if I knew they were getting in foal. We are having good success with on-farm pregnancies. He has a 75% 1st cycle conception rate.
Jos Posted From: 137.186.22.87
Posted on Saturday, May 08, 2004 - 05:16 pm:
From what I think you're saying, the less-teasing method results in lower volume? But you're thinking that is due to changing the collection bottle and removing some of the pre-ejaculate? (I'm a little hazy here on exactly what you mean!). Less teasing - as I note above - will result in less volume, but not because you are getting less pre-ejaculate (although that may be a minor contributory factor), but rather because you will get less secondary sex gland secretion, and that secretion represents the seminal plasma and gel fraction (if any).
There are 3 portions to an ejaculate:
Pre-ejaculate; this is the clear liquid that drips from the penis before collection - generally minimal in quantity, although with some stallions it can be significant.
Sperm-rich fraction; this is self explanatory in content, and is present in about the first three ejaculatory spurts.
Tail-fraction; this consists of the secondary sex gland secretions - seminal plasma and gel fraction - and is what will increase in volume with more teasing.
Remember that the sperm are in those first three spurts, and that won't increase with more teasing! Same first three spurts, same number of sperm! But increased teasing will result in the sometimes significant increase in seminal plasma volume. I remember one farm where a mare in heat had got out of her stall and stood in front of the stallion's stall all night... the stallion was cross-eyed in the morning, and when collected produced 350 ml of semen - terrible concentration though!
So, less teasing - even if it does require 2 jumps - is a good place to start. And as I mentioned above, if that doesn't work for you, learn to fractionate the ejaculate and catch only the first three ejaculatory spurts.
With respect to your observation that you had "analyzed the stallion pre-breeding season" and had "determined the concentrations and extender ratios". You can't do that!!! As you are now realising, every ejaculate is different. Sometimes not significantly, but that is not always the case, so it is essential that each ejaculate be evaluated and treated as an individual. If one does not do this, but tries to always extend at [say] 5:1, you are going to get abysmal results with some - if not all - shipments.
Why do these change? Well, in the height of the breeding season, the stallion is producing higher amounts of testosterone - you will have noticed that he is more responsive then than in the early or end of the breeding season perhaps. This higher level of testosterone also results in increased sperm production and output. Add to that, the fact that stallions are individuals, and may be a little more excited by a certain mare, or perhaps he has been standing in his stall thinking of "that certain mare" prior to being collected, and you will start to realise that you cannot consider them to be "sperm manufacturing machines" but must be considered an individual animal...
Good evaluation, extension and packaging of each ejaculate is a cornerstone of a successful semen shipping program.
Live cover or on-farm AI is not going to produce the same headaches for you, as you are finding with transported semen. The optimum on-farm insemination dose is 500 million progressively motile sperm, but there are not significant reductions in pregnancy rates until lower than 100 million PMS are used. Now, the average stallion produces enough sperm in a single ejaculate to inseminate between 5 and 15 mares... so you can perhaps see why on-farm work is not an issue!
Good luck and check back if you have any more questions!
Anonymous Posted From: 65.93.148.210
Posted on Sunday, May 09, 2004 - 12:42 pm:
Thanks for all of your advice!
Sorry for not clarifying though, we analyze the semen every breeding day but we were confident in his concentrations and volume before the start of the season. We arbitrarily (sp?) set a limit to the amount of mares he could service based on his initial figures, allowing for a decline at the end of the season. We hadn't anticipated on the concentration falling and the volume increasing. He teases for less than five minutes and is very receptive to the mare. The volume of pre-ejaculate when we do not get him on the first mount is approx. 40 ml, so in a collection that is 100-110 mL total after jumping only once, the concentration is much lower than if he jumps twice and we can remove the initial pre-ejaculate. Is this true that most of the pre-ejaculate is removed if he doesn't go on the first mount?
Also, we have been sending transported semen and the mares are settling on the first cycle "about" the same as on-farm rate so far this season. Our stud has as much as 11 billion P.M. sperm and as low as 6 billion P.M. on any breeding day.
What is the average first cycle conception rate for transported semen in your experience?
Thanks.
Jos Posted From: 137.186.22.3
Posted on Sunday, May 09, 2004 - 09:58 pm:
In order to determine what the maximum number of shipments is possible on a given day is, you have to perform a "milk down" schedule of collections. To do this, you collect stallions with big testicles for 7 days in a row, those with small testicles, 5 days in a row. On the 8th or 6th day respectively the total sperm numbers in the ejaculate will be representative of the total daily sperm output (TDSO) as you will have removed the gonadal reserves, and the sperm you are collecting are the ones that are released "fresh" that day. This is the only way to accurately obtain the statistic of the total number of daily shipments/mares bred per day.
If you are obtaining 40-ml of pre-ejaculate, obviously removal of that would result in a higher concentration once the sperm-rich fraction is obtained. What happens if you allow the stallion to mount the phantom, but do not introduce the AV? It is common in the wild for stallions to "test mount" mares without an erection, and it has been shown that allowing stallions to mount mares or phantoms without an erection can actually reduce the duration to ejaculation. Perhaps if you try this with your chap, he will also lose the pre-ejaculate on the ground, thereby avoiding the need to change bottles. It may also be a factor in the increased teasing effect, resulting in the larger volume of seminal plasma. I would perhaps try and see what happens if he gets up and doesn't get the stimulation from the AV the first time. He may even decide that he needs to get down to work right away!!!
If you are achieving a 75% first-cycle conception rate with transported semen, that is fine. Anything above 60% is acceptable. That may seem low, but it takes into account mares that are not suitable candidates for breeding, errors in the transportation, and dealing with mare owners or inseminators who really don't know what they're doing!
Anonymous Posted From: 69.156.226.140
Posted on Monday, May 31, 2004 - 10:19 am:
Jos Can you expand on this statement "If one does not do this, but tries to always extend at [say] 5:1, you are going to get abysmal results with some - if not all - shipments" Isn't there a range of concentration of cells per ml for shipping cooled semen. If the stallion 's concentration over the season ranges from say 320-450 x 10(6) cells per ml could always diluting 1:6 yield an appropriate dilution for shipment to the mare (46-64 x 10(6)cells per ml or 1.8 billion-2.5 billion cells/dose) Since I count with a hemocytometer I have to get a count quickly and dilute quickly. I'm not always confident in my technique for counting so I'd appreciate if you would clarify.
Jos Posted From: 137.186.22.5
Posted on Monday, May 31, 2004 - 11:27 am:
The range of concentration at which semen should be shipped is between 25 and 50 million sperm/ml.
There are many factors that can increase or decrease a stallion's sperm concentration on a given day. More teasing will increase his volume, and lower concentration for example, so if he has been standing thinking naughty thoughts in his stall, you may well get a different concentration from that which you will get on a day when he is feeling virtuous...
Consequently, simply extending at a given ratio will not provide you with the desired final concentration on a regular basis.
e.g.:
Stallion concentration day 1: 240 million/ml Ratio 1:8 Final concentration: 26.6 million/ml Total volume shipped to provide 1 billion sperm: 37.5 ml
Stallion concentration day 2: 160 million/ml Arbitrary ratio based on previous experience 1:8 Final concentration: 17.7 million/ml (below lower threshold for concentration) Total sperm shipped in previously used 37.5 ml: 663.75 million (sub-industry standard).
The difference in visual appearance between 240 and 160 million/ml will not be great.
Looking at a sample under the microscope on a regular slide will not provide an accurate estimate of concentration, as you are dealing with an incredibly thin sample, and doubling the thickness of the sample will double the apparent concentration.
Counting really is required to give a reliable quality product... and not counting could leave one open to a liability situation in the worst instance, as the sample CAN be counted at the receiving end - we do it all the time if we see a sample arrive that we feel is sub-standard.
Anonymous Posted From: 69.156.226.140
Posted on Monday, May 31, 2004 - 11:42 am:
Thank you. I've found this board to be so useful.
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