Was Seth Hancock Right About Overbreeding??

[llbean]

Hi Zinn,

You are 100% correct that this is all unproven speculation.

However, I'm not aware of any Scientists even trying to prove and/or disprove it and thus it isn't really the theory's fault that Scientific Data cannot be marshaled in support of it.

but where is the science to support that those mares stopped will produce inferior performing foals?

As far as I know this has not been studied by scientists. However, laymen have observed a significant drop-off in the SW percentage for top stallions since the era of 150+ Books began. Perhaps a less selective choosing of potential mates is entirely at fault, but the Sperm could very well also be to blame...

Are the remaining viable sperm inferior to sperm produced by the same stallion bred to fewer mares?

Perhaps yes, Perhaps no; my main point was that the less sperm = less high-quality sperm even if the Percentage of high Quality sperm remains the same (for instance, .0001% of 50,000 is 5, but .0001% of 100,000 is 10). Thus, there will be less competition for the Egg and a lower quality sperm will likely get there first, possibly resulting in a lower quality offspring.

I don't see any definitive evidence supporting the theory that more stallion covers results in fewer superior performing foals result.

Again, you are 100% correct; the idea that stallions with bigger books get far worse stats is based more on anecdotes than methodical statistical research. Hopefully someone qualified will take up the gauntlet of studying this all-too often ignored issue (just don't expect Coolmore to bankroll it!).

-llbean

[xfactor fan]

Two thing to add to the debate.

First the "super sperm" theory is being credited to Seth Hancock. He may know something the rest of us don't. However, he has an economic motivation to promote this theory. He keeps the foal crops low for his stallions, and is using rarity to keep the value of the foals high.
This make me wonder about the "super sperm" theory.

Second.
Has anyone taken a look at racing stats of 4, or 5 year olds, with birth dates, and foal crop size?

By 4-5 the early/late maturing lines should be caught up with each other. And a early in the year birth date was produced by "super sperm", and a June or July foal would be produced by a --"tired sperm". Or at least by a tired stallion.

You might also want to limit the selection to geldings--so that the sample isn't skewed by stallions being retired for stud duty early.

Another factor to adjust for is the natural bell curve of birth dates. Less foals in January and July, more in the middle of the breeding season.

There's probably a couple more factors that should be taken into account--maybe the age of the sire, and if there are one or two testicles making the sperm.

[xfactor fan]

Ok, a third thing.

Lets say that immature sperm don't wiggle quite as well as mature sperm. Wouldn't all the sperm in a breeding have the same level of maturity? So if the sample is all immature, the sperm would be competing against immature sperm, and following this theory, the egg would be fertilized by the best of the immature sperm.

Is there any indication that the maturity of the sperm affects the quality of the chromosomes inside the sperm head?
The tail yes, or even the packet of enzymes in the head, but the chromosomes in the head itself?

It sure doesn't seem likely that once the sperm is formed that anything can hurt the tightly coiled chromosomes and the genes they contain.

Somehow I don't think the stallions in control of which chromosomes end up in which sperm.

Like a stallions is going to say "today all my sperm are going have just the Y chromosome because I like sons". "Or since I'm gray, today all the sperm will have just my gray chromosome, 'cause the kids should look like their old man"
Or don't like that mare at all, so she's going to get a bad batch of sperm-claimers for her today.

[Pan Zareta]

xfactor fan,

NOTE: I don't know that this is passage from Stud is that which the originator of this thread had in mind, but it seems germaine to the discussion -
(p. 151-152, softcover edition 2003)

The breeding shed at Claiborne is the fastest I've been to, and much of that speed can be attributed to Hancock's conservative management of the stallions: he likes his stallions to have a light workload, a high libido, and a realistic stud fee. Back in his spacious and book-lined office after the breeding session, he explains why: 'This is kind of a crude analogy', he tells me. 'But if I have an ejaculate of semen that's thirty cc's and you have an ejaculate of semen that's five cc's, which ejaculate has the best chance of containing a sperm cell that is the absolute Michael Jordan of all sperm cells? Mine that's got thirty or yours that's got five? Which one?'

I admit that his sperm has the better chance.
'I've got better chances, right? Now, the scientist will say, "Well, that's ridiculous. It doesn't take but one sperm cell, and it makes no difference how weak or strong he might be, to get the mare in foal. And he's right. The weakest sperm cell of the bunch, he can swim up there. He can fertilize the egg. The mare can get in foal. She can have the foal. But what if I've got this Michael Jordan sperm cell and you've got this little weak one? Well, when my foal comes out, I have a great big, strong athletic foal. You might have a foal, yes, but he may be a little bitty of a runty that couldn't outrun me or you. I mean, maybe that's an oversimplification. But it's truly [p.152] the way I view it. And I know - I know for sure - that if I'm breeding my horse three times every two days, and you're breeding your horse three times every day, I'm gonna have thirty cc's and y'all are gonna have five. Now the other part of my little equation there might be wrong. But I know that my ejaculate is going to have more volume than yours. There ain't no doubt about that.'

I'd respectfully disagree that any extranuclear characteristics of the sperm are likely to cause a 'runty' but the point re. volume is well taken. It would be helpful to have "Michael Jordan sperm cell" better defined - are we talking how efficiently the sperm gets to the egg, or the quality of the nuclear DNA it carries?

Wouldn't all the sperm in a breeding have the same level of maturity?

Short answer: No. Ideally, immatures should not exceed a certain number per ejaculate - but I'm not certain what that number is in the domestic equine.

[xfactor fan]

Is there a connection between:

sperm motility, sperm maturity, volume of ejaculate
and nuclear DNA?

Seth and many other folks in this discussion seem to be making this connection. Strong swimmers contain better nuclear DNA. Is this true?

Sperm genesis involved reduction division, each sperm cell gets a random half of the parent chromosomes, and minor amounts of mtDNA. The chromosomes are then packaged into a sperm.

Is there a connection between the chromosomes and the sperm package?

If so, then there may be something to the "super sperm" theory, if not, perhaps this needs to be re thought.


In breeds where AI is practiced, the "sample" is divided, extended and loaded into straws. Is there any decline in quality in AI breeds vs. live cover breeds? In fact can anyone tell from performance if a foal results from a live cover, vs AI?


Just for the record, Stallions covering 200 mares /year are being overbred, and this is probably bad for the stallions long term health.

[mary syers]

Just an observation: In the 60's and 70's, when AI in horses became popular, great QH stallions, like Go Man Go were bred to ALOT of mares--over a thousand a year. Stakes percentages in the resulting foals was about 6% for Go Man Go. This seemed low to me, but I could never get a handle on whether the number of available stakes races in the QH compared to the number available in the TB, or what was an expected stakes winner rate in the QH. I know my own personal observation of some of the less than spectacular sons of Go Man Go was that they were inferior examples of the breed. They looked not quiet finished. But then I never got within eyeshot of the champions he produced. Mary Syers

[adrienne]

Just an observation: In the 60's and 70's, when AI in horses became popular, great QH stallions, like Go Man Go were bred to ALOT of mares--over a thousand a year. Stakes percentages in the resulting foals was about 6% for Go Man Go. This seemed low to me, but I could never get a handle on whether the number of available stakes races in the QH compared to the number available in the TB, or what was an expected stakes winner rate in the QH. I know my own personal observation of some of the less than spectacular sons of Go Man Go was that they were inferior examples of the breed. They looked not quiet finished. But then I never got within eyeshot of the champions he produced. Mary Syers

Before AI, a top stallion would have had a very selective book. He would have only had say, 50, spots in his book and his connections would have selected the best mares from those interested to breed to their stallion. Say... the best of 500 mares.

Then AI comes along and the connections of that top stallion no longer have to turn away mares because of the physical limitations of their stallion. Instead of being bred to the top 10%... he's getting bred to everything... including the bottom 10% of mares whose owners and desperately trying to improve upon

Tada. An overall extreme lowering of the quality of the offspring.

Besides, a stallion doesn't have to have any more output of semen when bred using AI, and usually less. You may get up to 7-10 doses out of one ejaculate. So what would have gone into ONE mare is going into TEN mares. In fact, if you're a smart breeder you can collect your stallion every OTHER day (or even every 4th day if you're cooling semen and breeding on-farm exclusively!) and be breeding him to a large number of mares!

But are we experiencing a rise in quality because of super sperm due to very relaxed and well-rested quarter horse stallions? No. Because quality of offspring is obviously related to the kind of mares a stallion is getting, which is obviously related to insanely large book sizes.

And that's my opinion on the subject.

~Adrienne

[Sysonby]

Not meaning to offend here or anything but I believe Fusaichi Pegasus was a June Foal as well as Fappiano - both by Mr. Prospector - it didn't seem to affect them much being end of the season breedings.

Not trying to be a smart aleck, but the idea of a June foal selling for over $4 million amazed me so much that I looked it up. FuPeg was born on April 12, 1997.

[llbean]

But are we experiencing a rise in quality because of super sperm due to very relaxed and well-rested quarter horse stallions? No.

But each one of those Sperm-Rich Ejaculates was divided up into 7-10 doses and therefore a much smaller Sperm Population goes into each mare.

If the ""Super-Sperm" theory is valid this will be a significant negative and thus the theory predicts A.I. will result in a lower average quality of offspring regardless of book quality.

-llbean

[llbean]

Is there a connection between the chromosomes and the sperm package?

If so, then there may be something to the "super sperm" theory, if not, perhaps this needs to be re thought.
.

Hi xfactor fan,

You have really hit the nail on the head Vis a Vie this theory.

Personally, it makes sense to me that there would be a connection as a Sperm is alive and the growth and structure of living things are always determined to a fairly large extent by their DNA.

Just as the structure and behavior of protozoa is strongly governed by its genes; it is reasonable to conclude that the structure and behavior of a Sperm is likewise strongly governed by its genes (and significantly, the Successful Sperm has no DNA save its Mitochondrial DNA that don't contribute to the Genotype of the Zygote).

-llbean

[xfactor fan]

Sperm Genesis in pretty simple terms.


http://distance.stcc.edu/AandP/AP/AP2pa ... ermato.htm

[Pete]

Very interesting thread all,

the notion of nervous energy is something that I have thought a lot about and my belief is that this was something that Tesio labeled because he didn't have the educational background to understand it better

I agree, or he chose not to express it more clearly.

Ashford and any farm that's breeding 4 times a day are being fair only to themselves. Their stallions will have less libido, less active sperm and less chance to get your mare booked when you want. The more mares that the over used stallion fail to stop - the greater the congestion in the shed since there is no down time.

Belong To Me (as an example) was an avid breeder in NY and soon after relocating to KY and shuttling was no longer.

Some of the very overbred stallions with a number of crops, like Woodman and Royal Academy, have modest numbers. It was suggested by someone else in this thread (sorry - I forgot who said it) that this is perhaps due (I'm paraphrasing) to an averaging of their book. Certainly a book of 60 mares can be far more selective than one of 200. The best stallions with huge books should have less moderation of quality in their books.

Especially north of Florida, being born earlier in the year (Jan and early Feb), present problems for getting the new born foal enough quality outdoor time. If I had to put a single word to describe January foals, it would be gawky. They don't light up the sales - even 2yo sales. Northern Dancer was a June foal.

Regards,

Pete

[adrienne]

But each one of those Sperm-Rich Ejaculates was divided up into 7-10 doses and therefore a much smaller Sperm Population goes into each mare.

If the ""Super-Sperm" theory is valid this will be a significant negative and thus the theory predicts A.I. will result in a lower average quality of offspring irregardless of book quality.

-llbean

Are you trying to say there is only ONE good sperm in each ejaculate? A billion sperm and ONE good one?

This makes no sense.

It doesn't make sense to me that the fitness of an offspring could depend on a one-in-a-billion chance.

Even if there were "super sperm" (which I wholeheartedly agree there are not)... surely at least one in 250 million (normal AI dose) would be up to the description. Otherwise the theory would make itself moot. (Because if there are only a few good sperm in an ejaculate those could be easily lost (died, pulled out with gel fraction, pushed out by uterine contractions, etc) and they wouldn't even have a chance most of the time. Semen is all about strength in numbers).

~Adrienne

[llbean]

Are you trying to say there is only ONE good sperm in each ejaculate? A billion sperm and ONE good one?

I never said nor implied any such thing. Regardless of the rate of Super-Sperm in a ejaculate, less Sperm Equals Less Super-Sperm. How hard is that to understand??

It doesn't make sense to me that the fitness of an offspring could depend on a one-in-a-billion chance.

Don't you understand that the whole idea behind the Super-Sperm theory is that the Super-Sperm is more likely to get there first than the weak sperm?? Therefore it is a much better than one in a billion chance even if your "out of nowhere" idea of there only being one Super-Sperm in each ejaculate is correct.

This is not a matter of pure chance even if for some reason you have a hard time thinking of something as not being random.

Even if there were "super sperm" (which I wholeheartedly agree there are not)...

Do you know what the word "agree" means? Because if you read my posts on this thread you'll see you aren't agreeing with me if you say there aren't super-sperm.

Even if there were "super sperm" (which I wholeheartedly agree there are not)... surely at least one in 250 million (normal AI dose) would be up to the description. Otherwise the theory would make itself moot.

I should make myself more clear; there are not, nor did I ever suggest that there are two separate kinds of sperm: super and regular. When I call some Sperm "Super", I only mean they are much better than most Sperm.

This DOES NOT mean that all super sperm are equally good and this should be understood as a continuum. Therefore, the Best Sperm in an A.I. sample will likely be inferior to the best Sperm in a Full Ejaculate in the same way that the highest I.Q. high schoolers in random sample of 1,000 will likely get significantly better scores than the highest I.Q. high schoolers in a random sample of only 100.

Think of it this way, will a College drawing on a high school population of 200,000 not get higher SAT Score Students than a College drawing on a high school population only 20,000?

-llbean

[adrienne]

Even if there were "super sperm" (which I wholeheartedly agree there are not)...

Do you know what the word "agree" means? Because if you read my posts on this thread you'll see you aren't agreeing with me if you say there aren't super-sperm.

I am agreeing with the idea of there NOT being super sperm.

I don't like internet arguments.

I would much rather say: I agree with the position opposite of yours rather than say I disagree with your position.

It's about being at least-semi-positive.

That is of course, only if someone actually cares enough to read closely.

~Adrienne