On Wednesday we collected our stallion & he gave 60ml with a concentration of 238 on a Quick Check. Today (Friday) we collected & he gave 35 ml with a concentration of 485 on the same Quick Check. I did the reading 3 times to make sure the number was correct & 485 was the lowest of the 3 reading. This is his 5th time collecting this spring - April 10 - May 15. Why would the concentration have such a range? I just purchased the Quick Check last week. It is brand new from Exodus so I'm doubtful it's functioning incorrectly. Preparation for both days were exactly the same, warmed curvette, etc. Last year his concentration ranged from 185 to 263 on a Spermacue. Only collected him 5 times last breeding season from March 24 - July 1st. He is 13 years old. Any ideas would be appreciated.
One of my frequent howls is that "volume and concentration alone don't mean anything" - it's only when you multiply the two together to get the total number of sperm in the ejaculate that you really have a meaningful number (the exception to that is if the concentration is so low as to make shipping difficult).
Another of my frequent howls is "you can't take a concentration count once and expect it to remain close to the same for every collection". Believe it or not, we run across people that take a sample of a collection to their vet (or someone) to count, and then use that number for calculations for the rest of the season! They even ship semen based on those calculations!
External influences can change volumes of ejaculate - the more a stallion is teased, the greater the volume of the ejaculate. That teasing may not be a human-involved teasing - if he happens to be stabled or paddocked next to a cute little filly who is in estrus this week, he'll probably do a pretty good job of teasing himself! Increased teasing however will not increase sperm output, just volume.
Think "tea bag"! You can take one tea bag, and make a very strong thimble full of tea (well, you could if you could get a tea bag in a thimble! ), or you could take a 5-gallon bucket and make a very weak 5 gallons of tea. The same thing holds for the sperm in the ejaculate - low volume, high concentration; high volume, low concentration.
Your numbers return these results:
60 ml x 238 million/ml = 14.28 billion sperm 35 ml x 485 million/ml = 16.975 billion sperm
In other words, the second collection apparently yielded just under 19% more than the first.
On top of the above, as ANY of the "mechanical" sperm counters may be "out" by up 20% when compared to hemacytometer counts (per research performed by us some years ago) and there is no correlation to unit or concentration for that margin of error, it could be that the readings were 9½% low on the first collection and 9½% high on the second! In other words, both are - believe it or not - in the same "ball field" numbers-wise.
All perfectly normal, and a good example of why it is essential to perform a sperm concentration evaluation on every ejaculate!
And your QuickCheck is probably performing just fine within the normal boundaries of margin of error for that type (not make - type!) of unit.
Not necessarily. Sperm are the irritant that cause inflammatory response, while seminal plasma is a mitigant that controls inflammatory response. So with the exception of mares with uterine clearance issues, where increased volumes will be likely to present a greater problem, the increased volume of seminal plasma doesn't typically present an issue.
Note that this is different from an AI situation, where the semen is diluted with extender. Once diluted, the mitigating effect of the seminal plasma is lost to a great extent.
Jos, thanks for the info. I feel a lot better knowing the Quick Check is not functioning incorrectly & the true numbers are less than 20% off. The tea bag explanation was helpful also. I had also read your research regarding the difference in hemacytometer counts so I was aware of that. This was our first "solo" collection so to speak as we usually have a vet or a repro expert there to take care of everything, but neither were available that day. I was worried we was doing something incorrectly. Thanks again. Terri
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